Name: practical use of rna interference: oral delivery of double-stranded rna in liposome carriers for cockroaches
Uploaded: 2018-05-01T14:45:00
Description: Watch this Scientific Journal Video about Practical Use of RNA Interference: Oral Delivery of Double-stranded RNA in Liposome Carriers for Cockroaches at JoVE.com

This study was supported by grants from Taiwan (Ministry of Science and Technology, MOST 100-2923-B-002-002-MY3 and 106-2313-B-002-011-MY3 to H.J.L.), the Czech Republic (Grant agency of South Bohemia University, GAJU grant 065/2017/P to Y.H.L), and Spain (Spanish Ministry of Economy and Competitiveness, grants CGL2012-36251 and CGL2015-64727-P to X.B., and the Catalan Government, grant 2014 SGR 619 to X.B.); it also received financial support from the European Fund for Economic and Regional Development (FEDER funds to X.B.).

1. Synthesis and Preparation of dsRNA
<ol>
	<li>Identify the dsRNA target sites in the 3&#39; untranslated region of the target genes. The dsTub is used for targeting the &#945;-tubulin (tub) gene (GenBank accession number: KX228233), and dsEGFP as a negative dsRNA control is designed from the sequence of enhanced green fluorescence protein (EGFP; GenBank accession number: LC311024).</li>
	<li>Perform standard PCR amplification to synthesize the dsRNA templates with gene-specific primers containing the T7 promoter sequ...

<ol>
	<li>Hammond, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dicing+and+slicing:+The+core+machinery+of+the+RNA+interference+pathway.">Dicing and slicing: The core machinery of the RNA interference pathway.</a> FEBS Lett. 579, 5822-5829 (2005).</li><li>Bell&#233;s, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Beyond+drosophila:+RNAi+in+vivo+and+functional+genomics+in+insects.">Beyond drosophila: RNAi in vivo and functional genomics in insects.</a> Annu. Rev. Entomol. 55, 111-128 (2010).</li><li>Wynant, N., Santos, D., Vanden Broeck, J., Jeon, K. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chapter+Five+-+Biological+Mechanisms+Determining+the+Success+of+RNA+Interference+in+Insects.">Chapter Five - Biological Mechanisms Determining the Success of RNA Interference in Insects.</a> International Review of Cell and Molecular Biology. 312, 139-167 (2014).</li><li>San Miguel, K., Scott, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+next+generation+of+insecticides:+dsRNA+is+stable+as+a+foliar-applied+insecticide.">The next generation of insecticides: dsRNA is stable as a foliar-applied insecticide.</a> Pest Manag. Sci. 72, 801-809 (2016).</li><li>Scott, J. G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Towards+the+elements+of+successful+insect+RNAi.">Towards the elements of successful insect RNAi.</a> J. Insect Physiol. 59, 1212-1221 (2013).</li><li>Joga, M. R., Zotti, M. J., Smagghe, G., Christiaens, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RNAi+efficiency,+systemic+properties,+and+novel+delivery+methods+for+pest+insect+control:+What+we+know+so+far.">RNAi efficiency, systemic properties, and novel delivery methods for pest insect control: What we know so far.</a> Front. Physiol. 7, (2016).</li><li>Garbutt, J. S., Bell&#233;s, X., Richards, E. H., Reynolds, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Persistence+of+double-stranded+RNA+in+insect+hemolymph+as+a+potential+determiner+of+RNA+interference+success:+Evidence+from+Manduca+sexta+and+Blattella+germanica.">Persistence of double-stranded RNA in insect hemolymph as a potential determiner of RNA interference success: Evidence from Manduca sexta and Blattella germanica.</a> J. Insect Physiol. 59, 171-178 (2013).</li><li>Arimatsu, Y., Kotani, E., Sugimura, Y., Furusawa, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Molecular+characterization+of+a+cDNA+encoding+extracellular+dsRNase+and+its+expression+in+the+silkworm,+Bombyx+mori.">Molecular characterization of a cDNA encoding extracellular dsRNase and its expression in the silkworm, Bombyx mori.</a> Insect Biochem. Mol. Biol. 37, 176-183 (2007).</li><li>Wang, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Variation+in+RNAi+efficacy+among+insect+species+is+attributable+to+dsRNA+degradation+in+vivo.">Variation in RNAi efficacy among insect species is attributable to dsRNA degradation in vivo.</a> Insect Biochem. Mol. Biol. 77, 1-9 (2016).</li><li>Wynant, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification,+functional+characterization+and+phylogenetic+analysis+of+double+stranded+RNA+degrading+enzymes+present+in+the+gut+of+the+desert+locust,+Schistocerca+gregaria.">Identification, functional characterization and phylogenetic analysis of double stranded RNA degrading enzymes present in the gut of the desert locust, Schistocerca gregaria.</a> Insect Biochem. Mol. Biol. 46, 1-8 (2014).</li><li>Huang, J. -. H., Belles, X., Lee, H. -. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+characterization+of+hypertrehalosemic+hormone+receptor+in+relation+to+hemolymph+trehalose+and+to+oxidative+stress+in+the+cockroach+Blattella+germanica.">Functional characterization of hypertrehalosemic hormone receptor in relation to hemolymph trehalose and to oxidative stress in the cockroach Blattella germanica.</a> Exp. Endocrinol. 2, 114 (2012).</li><li>Lin, Y. -. H., Lee, C. -. M., Huang, J. -. H., Lee, H. -. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circadian+regulation+of+permethrin+susceptibility+by+glutathione+S-transferase+(BgGSTD1)+in+the+German+cockroach+(Blattella+germanica).">Circadian regulation of permethrin susceptibility by glutathione S-transferase (BgGSTD1) in the German cockroach (Blattella germanica).</a> J. Insect Physiol. 65, 45-50 (2014).</li><li>Lozano, J., Kayukawa, T., Shinoda, T., Belles, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+role+for+taiman+in+insect+metamorphosis.">A role for taiman in insect metamorphosis.</a> PLOS Genet. 10, 1004769 (2014).</li><li>Lozano, J., Monta&#241;ez, R., Belles, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MiR-2+family+regulates+insect+metamorphosis+by+controlling+the+juvenile+hormone+signaling+pathway.">MiR-2 family regulates insect metamorphosis by controlling the juvenile hormone signaling pathway.</a> Proc. Natl. Acad. Sci. 112, 3740-3745 (2015).</li><li>Lin, Y. -. H., Huang, J. -. H., Liu, Y., Belles, X., Lee, H. -. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oral+delivery+of+dsRNA+lipoplexes+to+German+cockroach+protects+dsRNA+from+degradation+and+induces+RNAi+response.">Oral delivery of dsRNA lipoplexes to German cockroach protects dsRNA from degradation and induces RNAi response.</a> Pest Manag. Sci. 73, 960-966 (2017).</li><li>Gharavi, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chiral+cationic+polyamines+for+chiral+microcapsules+and+siRNA+delivery.">Chiral cationic polyamines for chiral microcapsules and siRNA delivery.</a> Bioorg. Med. Chem. Lett. 23, 5919-5922 (2013).</li><li>Whyard, S., Singh, A. D., Wong, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ingested+double-stranded+RNAs+can+act+as+species-specific+insecticides.">Ingested double-stranded RNAs can act as species-specific insecticides.</a> Insect Biochem. Mol. Biol. 39, 824-832 (2009).</li><li>Luo, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differential+responses+of+migratory+locusts+to+systemic+RNA+interference+via+double-stranded+RNA+injection+and+feeding.">Differential responses of migratory locusts to systemic RNA interference via double-stranded RNA injection and feeding.</a> Insect Mol. Biol. 22, 574-583 (2013).</li><li>Liu, J., Smagghe, G., Swevers, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transcriptional+response+of+BmToll9-1+and+RNAi+machinery+genes+to+exogenous+dsRNA+in+the+midgut+of+Bombyx+mori.">Transcriptional response of BmToll9-1 and RNAi machinery genes to exogenous dsRNA in the midgut of Bombyx mori.</a> J. Insect Physiol. 59, 646-654 (2013).</li><li>Airs, P. M., Bartholomay, L. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RNA+interference+for+mosquito+and+mosquito-borne+disease+control.">RNA interference for mosquito and mosquito-borne disease control.</a> Insects. 8, 4 (2017).</li><li>Taning, C. N. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Oral+RNAi+to+control+Drosophila+suzukii:+Laboratory+testing+against+larval+and+adult+stages.">Oral RNAi to control Drosophila suzukii: Laboratory testing against larval and adult stages.</a> J. Pest Sci. 89, 803-814 (2016).</li><li>Wu, S. Y., McMillan, N. A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipidic+systems+for+in+vivo+siRNA+delivery.">Lipidic systems for in vivo siRNA delivery.</a> AAPS J. 11, 639-652 (2009).</li><li>Tam, Y. Y. C., Chen, S., Cullis, P. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Advances+in+lipid+nanoparticles+for+siRNA+delivery.">Advances in lipid nanoparticles for siRNA delivery.</a> Pharmaceutics. 5, 498-507 (2013).</li><li>Xia, Y., Tian, J., Chen, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+surface+properties+on+liposomal+siRNA+delivery.">Effect of surface properties on liposomal siRNA delivery.</a> Biomaterials. 79, 56-68 (2016).</li></ol>

This protocol presents a method for effective RNAi through oral delivery of dsRNA lipoplexes, involving protection against ribonuclease digestion in the midgut juice of the German cockroach. As shown in other studies in various insect species, the poor RNAi effect through oral delivery of dsRNA is mostly accounted for by the degradation of dsRNA8,9,10. This protocol produces liposomes that serve as protective vehicles in oral de...

RNAi has been demonstrated as an effective method to knockdown gene expression through a mechanism of a post-transcriptional silencing pathway triggered by dsRNA molecules in many eukaryotes1. Over the past decade of study, RNAi has become a useful tool to study the functions of genes from development to behavior by depleting the expression of specific genes via injection and/or feeding of dsRNA in various taxa of insects2,3. Due to the specificity and robustness of the depleting effect, the application of RNAi is currently being considered as a potential strategy for pest control management4,5. However, the efficiency of RNAi varies widely between insect species, depending on the different genes being targeted and the delivery methods. A growing body of evidence suggests that the instability of dsRNA, which is degraded by ribonucleases, is a critical factor in the limited efficacy of RNAi5,6. For instance, the low RNAi sensitivity in Manduca sexta has been explained by the fact that the dsRNA mixed with hemolymph was quickly degraded within 1 hour7. Similarly, the presence of alkaline nucleases in the midgut, which efficiently degrade ingested dsRNA, is strongly correlated with low RNAi efficiency in different insect orders8,9,10.
The oral delivery of dsRNA is particularly interesting for the application of RNAi in a pest control strategy, but a method to retard the degradation of dsRNA by the nucleases in the midgut has not yet been developed, which would have the potential to ensure effective RNAi through feeding. However, the unresponsiveness of RNAi to oral delivery of dsRNA has been reported by feeding large amount of dsRNA, e.g. 50 &#181;g in Bombyx mori, or continuously feeding for 8 days (8 &#181;g dsRNA in total) in the locust species. The German cockroach, Blattella germinica, is highly sensitive to RNAi by the injection of dsRNA11,12,13,14, but is not responsive to dsRNA through feeding. Recently, Lin et al. (2017) have demonstrated that the dsRNA encapsulated with liposome carriers results in successful RNAi to knockdown the &#945;-tubulin gene expression in the midgut and trigger significant mortality of the German cockroach15. As the degradation of dsRNA in the midgut is the limiting factor for oral RNAi, the liposome carriers serve as a vehicle to protect dsRNA from degradation, which is readily applicable in other insects with strong nuclease activities in the gut. Of note, the reason for choosing the particular transfection reagent (see Table of Materials) we used as liposome carrier in the current protocol is that it has been tested for insect cell line transfection with less toxicity, according to the manufacturer&#39;s instructions. According to the comparison of different liposome transfection systems in Gharavi et al. (2013)16, the efficiency of transfecting small interfering RNA (siRNA) is approximately the same between this and other commercially available systems that have been used for dsRNA delivery systems in other insects17,18.Furthermore, our feeding method is careful enough to ensure the proper amount of dsRNA is ingested by each cockroach, and that the results are robust and confirmed. In summary, the present protocol and results demonstrate that using dsRNA lipoplexes improves dsRNA stability and opens the door to the design of the strategy oral delivery of RNAi, which is a promising approach for pest control in the future.

<table border="0" cellpadding="0" cellspacing="0" style="width:1124px;" width="1123">
	<colgroup>
		<col />
		<col />
		<col />
		<col />
	</colgroup>
	<tbody>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">GenJe Plus DNA in vitro Transfection reagent</td>
			<td style="width:133px;">SignaGen</td>
			<td style="width:157px;">SL100499</td>
			<td style="width:481px;">for lipoplexes preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Blend Taq plus</td>
			<td style="width:133px;">TOYOBO&#160;</td>
			<td style="width:157px;">BTQ-201</td>
			<td>for PCR</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Fast SYBR Green Master Mix</td>
			<td style="width:133px;">ABI&#160;</td>
			<td style="width:157px;">4385612</td>
			<td>for qPCR</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">FirstChoice RLM-RACE Kit</td>
			<td style="width:133px;">Invitrogen</td>
			<td style="width:157px;">AM1700</td>
			<td>for 3&#39; UTR identification&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">MEGAscript T7 Transcription Kit</td>
			<td style="width:133px;">Invitrogen</td>
			<td style="width:157px;">AMB13345</td>
			<td>for dsRNA synthesis</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">TURBO DNase</td>
			<td style="width:133px;">Invitrogen</td>
			<td style="width:157px;">AM2239</td>
			<td>remove DNA template from dsRNA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">TRIzol</td>
			<td style="width:133px;">Invitrogen</td>
			<td style="width:157px;">15596018</td>
			<td>for dsRNA or total RNA extraction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">RQ1 RNase-Free Dnase</td>
			<td style="width:133px;">Promega</td>
			<td style="width:157px;">M6101</td>
			<td>remove DNA template from total RNA&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">chloroform&#160;</td>
			<td>Sigma-Aldrich</td>
			<td style="width:157px;">C2432</td>
			<td>for dsRNA or total RNA extraction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">2-Propanol</td>
			<td>Sigma-Aldrich</td>
			<td style="width:157px;">I9516</td>
			<td>for dsRNA or total RNA extraction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">ethanol</td>
			<td>Sigma-Aldrich</td>
			<td>24102</td>
			<td>for dsRNA or total RNA extraction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">Diethyl pyrocarbonate, DEPC</td>
			<td>Sigma-Aldrich</td>
			<td style="width:157px;">D5758</td>
			<td>for RNase free water preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">glucose solution</td>
			<td>Sigma-Aldrich</td>
			<td style="width:157px;">G3285</td>
			<td>for lipoplexes preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sodium chloride, NaCl</td>
			<td>Sigma-Aldrich</td>
			<td style="width:157px;">S7653</td>
			<td>insect saline buffer formula</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">Potassium chloride, KCl</td>
			<td>Sigma-Aldrich</td>
			<td style="width:157px;">P9333</td>
			<td>insect saline buffer formula</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;width:352px;">Calcium chloride, CaCl2</td>
			<td>Sigma-Aldrich</td>
			<td>C1016</td>
			<td>insect saline buffer formula</td>
		</tr>
		<tr height="25">
			<td height="25" style="height:25px;">Magnesium chloride hexahydrate, MgCl2.6H2O</td>
			<td>Sigma-Aldrich</td>
			<td style="width:157px;">M2670</td>
			<td>insect saline buffer formula</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">EGTA&#160;</td>
			<td>Sigma-Aldrich</td>
			<td style="width:157px;">E3889</td>
			<td>enzyme inhibitor&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">dissecting scissor</td>
			<td style="width:133px;">F.S.T.</td>
			<td style="width:157px;"></td>
			<td>cockroach dissection</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">fine tweezers</td>
			<td style="width:133px;">F.S.T.</td>
			<td style="width:157px;"></td>
			<td>cockroach dissection</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">flexible tweezer</td>
			<td style="width:133px;">F.S.T.</td>
			<td style="width:157px;"></td>
			<td>cockroach holding&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">pipetman</td>
			<td style="width:133px;">RAININ</td>
			<td style="width:157px;">P10</td>
			<td>sample preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">microcentrifuge tube</td>
			<td style="width:133px;">Axygen</td>
			<td>MCT175C, PCR02C</td>
			<td>sample preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">pipette tip&#160;</td>
			<td style="width:133px;">Axygen</td>
			<td></td>
			<td>sample preparation</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">vortexter</td>
			<td style="width:133px;">Digisystem</td>
			<td style="width:157px;">vm1000</td>
			<td>sample preparation</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">Minispin centrifuge</td>
			<td style="width:133px;">The Gruffin Group</td>
			<td style="width:157px;">GMC 206</td>
			<td>for liquid spin down&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Centrifuge</td>
			<td style="width:133px;">ALC</td>
			<td style="width:157px;">PK121R</td>
			<td>sample preparation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">pH meter&#160;</td>
			<td style="width:133px;">JENCO</td>
			<td style="width:157px;">6071</td>
			<td>for pH adjust</td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;">micro-volume spectrophotometer</td>
			<td style="width:133px;">Quawell</td>
			<td style="width:157px;">Q3000</td>
			<td>nucleic acid quantitative</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">PCR Thermal cycler</td>
			<td style="width:133px;">ABI&#160;</td>
			<td style="width:157px;">2720</td>
			<td>for template PCR or&#160; dsRNA synthesis incubation&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">quantitative real-time PCR</td>
			<td style="width:133px;">ABI&#160;</td>
			<td style="width:157px;">StepOne plus</td>
			<td>gene expression quantitative</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Centrifugal Vacuum Concentrators</td>
			<td style="width:133px;">eppendorf</td>
			<td style="width:157px;">5301</td>
			<td>for dsRNA or total RNA extraction</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Multipette&#160;</td>
			<td style="width:133px;">eppendorf</td>
			<td style="width:157px;">xstream</td>
			<td>for real-time PCR sample loading&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Agarose I</td>
			<td style="width:133px;">amresco</td>
			<td style="width:157px;">0710</td>
			<td>for nucleic acid electrophoresis</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">tub gene specfifc forward preimer</td>
			<td style="width:133px;">tri-I biotech</td>
			<td style="width:157px;"></td>
			<td>GGG ACA AGC CGG AGT GCA GA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">tub gene specfifc reverse preimer</td>
			<td style="width:133px;">tri-I biotech</td>
			<td style="width:157px;"></td>
			<td>TCC TGC TCC TGT CTC GCT GA</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">dsTub template forward primer</td>
			<td style="width:133px;">tri-I biotech</td>
			<td style="width:157px;"></td>
			<td>TAA TAC GAC TCA CTA TAG GGA CAA GCC GGA GTG CAG&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">dsTub template reverse primer</td>
			<td style="width:133px;">tri-I biotech</td>
			<td style="width:157px;"></td>
			<td>TAA TAC GAC TCA CTA TAG GGT CCT GCT CCT GTC TCG CTG&#160;</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">dsEGFP template forward preimer</td>
			<td style="width:133px;">tri-I biotech</td>
			<td style="width:157px;"></td>
			<td>TAA TAC GAC TCA CTA TAG GGT ATG GTG AGC AAG GGC GAG GAG</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">dsEGFP template reverse preimer</td>
			<td style="width:133px;">tri-I biotech</td>
			<td style="width:157px;"></td>
			<td>TAA TAC GAC TCA CTA TAG GGT GGC GGA TCT TGA AGT TCA CC</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">tub qPCR forward primer</td>
			<td style="width:133px;">tri-I biotech</td>
			<td style="width:157px;"></td>
			<td>GGA CCG CAT CAG GAA ACT GGC</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">tub qPCR reverse preimer</td>
			<td style="width:133px;">tri-I biotech</td>
			<td style="width:157px;"></td>
			<td>CCA CAG ACA GCC TCT CCA TGA GC</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">ef1 qPCR forward primer</td>
			<td style="width:133px;">tri-I biotech</td>
			<td style="width:157px;"></td>
			<td>CGC TTG AGG AAA TCA AGA AGG A</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:352px;">ef1 qPCRreverse preimer</td>
			<td style="width:133px;">tri-I biotech</td>
			<td style="width:157px;"></td>
			<td>CCT GCA GAG GAA GAC GAA G</td>
		</tr>
	</tbody>
</table>

practical use of rna interference: oral delivery of double-stranded rna in liposome carriers for cockroaches

RNA interference (RNAi) has been widely applied for uncovering the biological functions of numerous genes, and has been envisaged as a pest control tool operating by disruption of essential gene expression. Although different methods, such as injection, feeding, and soaking, have been reported for successful delivery of double-stranded RNA (dsRNA), the efficiency of RNAi through oral delivery of dsRNA is highly variable among different insect groups. The German cockroach, Blattella germanica, is highly sensitive to the injection of dsRNA, as shown by many studies published previously. The present study describes a method to demonstrate that the dsRNA encapsulated with liposome carriers is sufficient to retard the degradation of dsRNA by midgut juice. Notably, the continuous feeding of dsRNA encapsulated by liposomes significantly reduces the tubulin expression in the midgut, and led to the death of cockroaches. In conclusion, the formulation and utilization of dsRNA lipoplexes, which protect dsRNA against nucleases, could be a practical use of RNAi for insect pest control in the future.

A simplified scheme of the protocol for the oral delivery of dsRNA is presented in Figure 1, where the key steps for preparation of dsRNA lipoplexes are shown.
In order to investigate the protection given by liposome carriers upon dsRNA degradation in the midgut juice of B. germanica, an ex vivo assay where dsTub lipoplexes were incubated with midgut juice was conducted, and the in...

Watch this Scientific Journal Video about Practical Use of RNA Interference: Oral Delivery of Double-stranded RNA in Liposome Carriers for Cockroaches at JoVE.com

Practical Use of RNA Interference: Oral Delivery of Double-stranded RNA in Liposome Carriers for Cockroaches

This manuscript demonstrates the depletion of gene expression in the midgut of the German cockroach through oral ingestion of double-stranded RNA encapsulated in liposomes.

RNA interference (RNAi) has been widely applied for uncovering the biological functions of numerous genes, and has been envisaged as a pest control tool ...

The overall goal of this protocol is to deplete gene expression in the gut of cockroaches using RNA interference via oral ingestion of double-stranded RNA encapsulated in liposome carriers. This method can help answer key questions in the development of new pest control methods, such as can knocking down essential genes in the open field kill pests? The main advantage of this technique is that liposome protects the gene-specific double-stranded RNA to ensure its delivery to the target cell.Demonstrating the procedure will be Jia-Hsin Huang, a postdoc, and Yun Liu, a technician from my laboratory. To begin, anesthetize the cockroaches on ice until they do not move for three minutes. Then, pick up an insect using the thumb and index finger to access its ventral side.Next, use dissecting scissors to cut the tip of a coxa of a hind leg off between the coxa and the trochanter. Cutting elsewhere on the coxa is less efficient for the hemolymph collections. Now, position a 10-microliter micropipette at the incision, and squeeze the abdomen gently while drawing up the bleeding hemolymph.Repeat this process until the hemolymph from five cockroaches has been collected into a single microcentrifuge tube. Next, briefly spin down the pooled hemolymph for 10 seconds. Then, combine 10 microliters of hemolymph with 50 microliters of 1x insect saline buffer.Now, centrifuge the diluted hemolymph for 10 minutes to pull the hemocytes out of solution. Then, transfer the supernatant to a new tube. Lastly, quantify the total protein concentration using a microvolume UV-Vis spectrophotometer, and adjust the concentration of each sample to six milligrams of protein per microliter.To collect midgut juice, first, anesthetize the cockroaches on ice. Then, transfer one to a dissection plate loaded with cold 1x insect saline buffer, and use insect pins to secure it ventral side up. Now, dissect the abdomen using fine tweezers.Then, remove the entire gut, and transfer it to a fresh dish with 1x insect saline buffer. Next, isolate the midgut, which is the region between the crop and the Malpighian tubules. To do so, remove the front part of the animal and remove the hindgut.Next, quickly transfer the midgut to a microcentrifuge tube with 100 microliters of insect saline buffer. Collect the midguts from six cockroaches into the same tube. Then, vortex the tube for 10 seconds.Next, centrifuge the mixture for 10 minutes to separate out the hemocytes and gut tissues. Then, transfer the supernatant to a clean microcentrifuge tube, and adjust the concentration to six milligrams of protein per microliter. Double-stranded RNA lipoplexes must be used within an hour of preparation.During their preparation, be sure to combine all of the diluted reagent with the diluted double-stranded RNA at the same time. Then, quickly vortex and incubate the mixture. Once ready, mix four microliters of the double-stranded RNA solution with 10 microliters of insect saline buffer as a control, or mix it with 10 microliters of extracted enzymes taken from hemolymph or midgut juice.Next, make an enzyme-inhibited control by adding two microliters of EGTA. Otherwise, add two microliters of RNase-free water. Then, incubate the samples for an hour or longer at 25 degrees Celsius.After the incubation, add 200 microliters of extraction reagent and 40 microliters of chloroform, and then vortex. Next, centrifuge the samples for 10 minutes. Next, transfer 150 microliters of each supernatant to a new tube, and precipitate the double-stranded RNA from each sample by adding 150 microliters of isopropanol and incubating the samples on ice for 15 minutes.After the incubation, centrifuge the samples again and discard the supernatant. Then, wash the RNA pellets twice by adding 200 microliters of the 70%ethanol to each pellet and centrifuging the tube. After the second wash, dry the double-stranded RNA pellets using a centrifugal vacuum concentrator for three minutes.Then, resuspend the pellets in 10 microliters of RNase-free water. Finally, check the integrity of the treated double-stranded RNA using a 1.5%agarose gel. Feed the cockroaches twice per day, one hour after lights on and one hour before lights off.Do this for eight or 16 days without breaks. During this time, the cockroaches should be otherwise starved of water. For the feeding, have freshly prepared double-stranded RNA lipoplexes and naked double-stranded RNA available.For the bolus, use with four microliters of double-stranded RNA lipoplexes or 250 nanograms of naked double-stranded RNA. To feed a cockroach, first, grab it by the wings using flexible forceps. Do not grab the body parts of a cockroach.Then, slowly pipette the droplet of solution close to the mouthparts, and watch as the roach ingests the droplet. After the last feeding, provide water bottles to the roaches. Throughout the feeding period, assess the insects daily to check for mortality and remove any roaches that are no longer moving from the experiment.Continuous oral administration of double-stranded tub lipoplexes was able to decrease tubulin expression in the midgut from 40%at day nine to 60%at day 17. By comparison, naked double-stranded RNA had no effect. This is most likely due to finding that exposure of the naked double-stranded RNA to midgut juice resulted in degradation within an hour, whereas the liposome-conjugated double-stranded RNA remained stable.Not only did RNA levels decrease, but continuous feeding of the tubulin double-stranded RNA lipoplexes also resulted in significant lethality. This is unlikely to be due to the vector, as lipoplexes carrying double-stranded RNA to EGFP resulted in no lethality. While attempting this oral delivery system of RNA interference, it is important to perform a continuous feeding of double-stranded RNA for several days.Once mastery, the feeding step can be done in two minutes per insect if it is performed properly. If needed, different formulation of liposome nanoparticles can be applied to improve the feeding procedure and RNAi efficiency. Ultimately, this technique has made it feasible for researchers in the field of the pest management to explore new control strategies using RNAi.

practical-use-rna-interference-oral-delivery-double-stranded-rna

Research

JoVE Journal

Biology

In vitro Transcription and Capping of Gaussia Luciferase mRNA Followed by HeLa Cell Transfection

In vitro transcription is the synthesis of RNA transcripts by RNA polymerase from a linear DNA template containing the corresponding promoter sequence (T7, T3, SP6) and the gene to be transcribed (Figure 1A). A typical transcription reaction consists of the template DNA, RNA polymerase, ribonucleotide triphosphates, RNase inhibitor and buffer containing Mg2+ ions.
Large amounts of high quality RNA are often required for a variety of applications. Use of in vitro transcription has been reported for RNA structure and function studies such as splicing1, RNAi experiments in mammalian cells2, antisense RNA amplification by the "Eberwine method"3, microarray analysis4 and for RNA vaccine studies5. The technique can also be used for producing radiolabeled and dye labeled probes6. Warren, et al. recently reported reprogramming of human cells by transfection with in vitro transcribed capped RNA7. The T7 High Yield RNA Synthesis Kit from New England Biolabs has been designed to synthesize up to 180 &mu;g RNA per 20 &mu;l reaction. RNA of length up to 10kb has been successfully transcribed using this kit. Linearized plasmid DNA, PCR products and synthetic DNA oligonucleotides can be used as templates for transcription as long as they have the T7 promoter sequence upstream of the gene to be transcribed.
Addition of a 5' end cap structure to the RNA is an important process in eukaryotes. It is essential for RNA stability8, efficient translation9, nuclear transport10 and splicing11. The process involves addition of a 7-methylguanosine cap at the 5' triphosphate end of the RNA. RNA capping can be carried out post-transcriptionally using capping enzymes or co-transcriptionally using cap analogs. In the enzymatic method, the mRNA is capped using the Vaccinia virus capping enzyme12,13. The enzyme adds on a 7-methylguanosine cap at the 5' end of the RNA using GTP and S-adenosyl methionine as donors (cap 0 structure). Both methods yield functionally active capped RNA suitable for transfection or other applications14 such as generating viral genomic RNA for reverse-genetic systems15 and crystallographic studies of cap binding proteins such as eIF4E16.
In the method described below, the T7 High Yield RNA Synthesis Kit from NEB is used to synthesize capped and uncapped RNA transcripts of Gaussia luciferase (GLuc) and Cypridina luciferase (CLuc). A portion of the uncapped GLuc RNA is capped using the Vaccinia Capping System (NEB). A linearized plasmid containing the GLuc or CLuc gene and T7 promoter is used as the template DNA. The transcribed RNA is transfected into HeLa cells and cell culture supernatants are assayed for luciferase activity. Capped CLuc RNA is used as the internal control to normalize GLuc expression.

In vitro Transcription and Capping of Gaussia Luciferase mRNA Followed by HeLa Cell Transfection

This method describes high yield in vitro synthesis of both capped and uncapped mRNA from a linearized plasmid containing the Gaussia luciferase (GLuc) gene. The RNA is purified and a fraction of the uncapped RNA is enzymatically capped using the Vaccinia virus capping enzyme. In the final step, the mRNA is transfected into HeLa cells and cell culture supernatants are assayed for luciferase activity.

In vitro transcription is the synthesis of RNA transcripts by RNA polymerase from a linear DNA template containing the corresponding promoter sequence ...

Chromatin Isolation by RNA Purification (ChIRP)

Long noncoding RNAs are key regulators of chromatin states for important biological processes such as dosage compensation, imprinting, and developmental gene expression 1,2,3,4,5,6,7. The recent discovery of thousands of lncRNAs in association with specific chromatin modification complexes, such as Polycomb Repressive Complex 2 (PRC2) that mediates histone H3 lysine 27 trimethylation (H3K27me3), suggests broad roles for numerous lncRNAs in managing chromatin states in a gene-specific fashion 8,9. While some lncRNAs are thought to work in cis on neighboring genes, other lncRNAs work in trans to regulate distantly located genes. For instance, Drosophila lncRNAs roX1 and roX2 bind numerous regions on the X chromosome of male cells, and are critical for dosage compensation 10,11. However, the exact locations of their binding sites are not known at high resolution. Similarly, human lncRNA HOTAIR can affect PRC2 occupancy on hundreds of genes genome-wide 3,12,13, but how specificity is achieved is unclear. LncRNAs can also serve as modular scaffolds to recruit the assembly of multiple protein complexes. The classic trans-acting RNA scaffold is the TERC RNA that serves as the template and scaffold for the telomerase complex 14; HOTAIR can also serve as a scaffold for PRC2 and a H3K4 demethylase complex 13.
Prior studies mapping RNA occupancy at chromatin have revealed substantial insights 15,16, but only at a single gene locus at a time. The occupancy sites of most lncRNAs are not known, and the roles of lncRNAs in chromatin regulation have been mostly inferred from the indirect effects of lncRNA perturbation. Just as chromatin immunoprecipitation followed by microarray or deep sequencing (ChIP-chip or ChIP-seq, respectively) has greatly improved our understanding of protein-DNA interactions on a genomic scale, here we illustrate a recently published strategy to map long RNA occupancy genome-wide at high resolution 17. This method, Chromatin Isolation by RNA Purification (ChIRP) (Figure 1), is based on affinity capture of target lncRNA:chromatin complex by tiling antisense-oligos, which then generates a map of genomic binding sites at a resolution of several hundred bases with high sensitivity and low background. ChIRP is applicable to many lncRNAs because the design of affinity-probes is straightforward given the RNA sequence and requires no knowledge of the RNA's structure or functional domains.

Chromatin Isolation by RNA Purification ChIRP

ChIRP is a novel and rapid technique to map genomic binding sites of long noncoding RNAs (lncRNAs). The method takes advantage of the specificity of anti-sense tiling oligonucleotides to allow the enumeration of lncRNA-bound genomic sites.

Long noncoding RNAs are key regulators of chromatin states for important biological processes such as dosage compensation, imprinting, and developmental ...

Substrate Generation for Endonucleases of CRISPR/Cas Systems

The interaction of viruses and their prokaryotic hosts shaped the evolution of bacterial and archaeal life. Prokaryotes developed several strategies to evade viral attacks that include restriction modification, abortive infection and CRISPR/Cas systems. These adaptive immune systems found in many Bacteria and most Archaea consist of clustered regularly interspaced short palindromic repeat (CRISPR) sequences and a number of CRISPR associated (Cas) genes (Fig. 1) 1-3. Different sets of Cas proteins and repeats define at least three major divergent types of CRISPR/Cas systems 4. The universal proteins Cas1 and Cas2 are proposed to be involved in the uptake of viral DNA that will generate a new spacer element between two repeats at the 5' terminus of an extending CRISPR cluster 5. The entire cluster is transcribed into a precursor-crRNA containing all spacer and repeat sequences and is subsequently processed by an enzyme of the diverse Cas6 family into smaller crRNAs 6-8. These crRNAs consist of the spacer sequence flanked by a 5' terminal (8 nucleotides) and a 3' terminal tag derived from the repeat sequence 9. A repeated infection of the virus can now be blocked as the new crRNA will be directed by a Cas protein complex (Cascade) to the viral DNA and identify it as such via base complementarity10. Finally, for CRISPR/Cas type 1 systems, the nuclease Cas3 will destroy the detected invader DNA 11,12 .
These processes define CRISPR/Cas as an adaptive immune system of prokaryotes and opened a fascinating research field for the study of the involved Cas proteins. The function of many Cas proteins is still elusive and the causes for the apparent diversity of the CRISPR/Cas systems remain to be illuminated. Potential activities of most Cas proteins were predicted via detailed computational analyses. A major fraction of Cas proteins are either shown or proposed to function as endonucleases 4.
Here, we present methods to generate crRNAs and precursor-cRNAs for the study of Cas endoribonucleases. Different endonuclease assays require either short repeat sequences that can directly be synthesized as RNA oligonucleotides or longer crRNA and pre-crRNA sequences that are generated via in vitro T7 RNA polymerase run-off transcription. This methodology allows the incorporation of radioactive nucleotides for the generation of internally labeled endonuclease substrates and the creation of synthetic or mutant crRNAs. Cas6 endonuclease activity is utilized to mature pre-crRNAs into crRNAs with 5'-hydroxyl and a 2',3'-cyclic phosphate termini.

CRISPR/Cas systems mediate adaptive immunity in Bacteria and Archaea. Many Cas proteins are proposed to act as endoribonucleases acting on crRNA precursors of varying length. Here we illustrate three different approaches to generate pre-crRNA substrates for the biochemical analysis of Cas endonuclease activity.

The  interaction of viruses and their prokaryotic hosts shaped the evolution of  bacterial and archaeal life. Prokaryotes developed several strategies to ...

Using RNA-mediated Interference Feeding Strategy to Screen for Genes Involved in Body Size Regulation in the Nematode C. elegans

Double-strand RNA-mediated interference (RNAi) is an effective strategy to knock down target gene expression1-3. It has been applied to many model systems including plants, invertebrates and vertebrates. There are various methods to achieve RNAi in vivo4,5. For example, the target gene may be transformed into an RNAi vector, and then either permanently or transiently transformed into cell lines or primary cells to achieve gene knockdown effects; alternatively synthesized double-strand oligonucleotides from specific target genes (RNAi oligos) may be transiently transformed into cell lines or primary cells to silence target genes; or synthesized double-strand RNA molecules may be microinjected into an organism. Since the nematode C. elegans uses bacteria as a food source, feeding the animals with bacteria expressing double-strand RNA against target genes provides a viable strategy6. Here we present an RNAi feeding method to score body size phenotype. Body size in C. elegans is regulated primarily by the TGF- &beta; - like ligand DBL-1, so this assay is appropriate for identification of TGF-&beta; signaling components7. We used different strains including two RNAi hypersensitive strains to repeat the RNAi feeding experiments. Our results showed that rrf-3 strain gave us the best expected RNAi phenotype. The method is easy to perform, reproducible, and easily quantified. Furthermore, our protocol minimizes the use of specialized equipment, so it is suitable for smaller laboratories or those at predominantly undergraduate institutions.

Using RNA-mediated Interference Feeding Strategy to Screen for Genes Involved in Body Size Regulation in the Nematode C. elegans

We demonstrate how to use the RNAi feeding technique to knock down target genes and score body size phenotype in C. elegans. This method could be used for a large scale screen to identify potential genetic components of interest, such as those involved in body size regulation by DBL-1/TGF-&beta; signaling.

Double-strand RNA-mediated interference (RNAi) is an effective strategy to knock down target gene expression1-3. It has been applied to many model systems ...

Depletion of Ribosomal RNA for Mosquito Gut Metagenomic RNA-seq

The mosquito gut accommodates dynamic microbial communities across different stages of the insect's life cycle. Characterization of the genetic capacity and functionality of the gut community will provide insight into the effects of gut microbiota on mosquito life traits. Metagenomic RNA-Seq has become an important tool to analyze transcriptomes from various microbes present in a microbial community. Messenger RNA usually comprises only 1-3% of total RNA, while rRNA constitutes approximately 90%. It is challenging to enrich messenger RNA from a metagenomic microbial RNA sample because most prokaryotic mRNA species lack stable poly(A) tails. This prevents oligo d(T) mediated mRNA isolation. Here, we describe a protocol that employs sample derived rRNA capture probes to remove rRNA from a metagenomic total RNA sample. To begin, both mosquito and microbial small and large subunit rRNA fragments are amplified from a metagenomic community DNA sample. Then, the community specific biotinylated antisense ribosomal RNA probes are synthesized in vitro using T7 RNA polymerase. The biotinylated rRNA probes are hybridized to the total RNA. The hybrids are captured by streptavidin-coated beads and removed from the total RNA. This subtraction-based protocol efficiently removes both mosquito and microbial rRNA from the total RNA sample. The mRNA enriched sample is further processed for RNA amplification and RNA-Seq.

A ribosomal RNA (rRNA) depletion protocol was developed to enrich messenger RNA (mRNA) for RNA-seq of the mosquito gut metatranscriptome. Sample specific rRNA probes, which were used to remove rRNA via subtraction, were created from the mosquito and its gut microbes. Performance of the protocol can result in the removal of approximately 90-99% of rRNA.

The mosquito gut accommodates dynamic microbial communities across different stages of the insect's life cycle. Characterization of the genetic capacity ...

RNA Catalyst as a Reporter for Screening Drugs against RNA Editing in Trypanosomes

Substantial progress has been made in determining the mechanism of mitochondrial RNA editing in trypanosomes. Similarly, considerable progress has been made in identifying the components of the editosome complex that catalyze RNA editing. However, it is still not clear how those proteins work together. Chemical compounds obtained from a high-throughput screen against the editosome may block or affect one or more steps in the editing cycle. Therefore, the identification of new chemical compounds will generate valuable molecular probes for dissecting the editosome function and assembly. In previous studies, in vitro editing assays were carried out using radio-labeled RNA. These assays are time consuming, inefficient and unsuitable for high-throughput purposes. Here, a homogenous fluorescence-based &#8220;mix and measure&#8221; hammerhead ribozyme in vitro reporter assay to monitor RNA editing, is presented. Only as a consequence of RNA editing of the hammerhead ribozyme a fluorescence resonance energy transfer (FRET) oligoribonucleotide substrate undergoes cleavage. This in turn results in separation of the fluorophore from the quencher thereby producing a signal. In contrast, when the editosome function is inhibited, the fluorescence signal will be quenched. This is a highly sensitive and simple assay that should be generally applicable to monitor in vitro RNA editing or high throughput screening of chemicals that can inhibit the editosome function.

A highly sensitive ribozyme-based assay, applicable to high-throughput screening of chemicals targeting the unique process of RNA editing in trypanosomatid pathogens, is described in this paper. Inhibitors can be used as tools for hypothesis-driven analysis of the RNA editing process and ultimately as therapeutics.

Substantial progress has been made in determining the mechanism of mitochondrial RNA editing in trypanosomes. Similarly, considerable progress has been ...

Larval RNA Interference in the Red Flour Beetle, Tribolium castaneum

The red flour beetle, Tribolium&#160;castaneum, offers a repertoire of experimental tools for genetic and developmental studies, including a fully annotated genome sequence, transposon-based transgenesis, and effective RNA interference (RNAi). Among these advantages, RNAi-based gene knockdown techniques are at the core of Tribolium research. T. castaneum show a robust systemic RNAi response, making it possible to perform RNAi at any life stage by simply injecting double-stranded RNA (dsRNA) into the beetle&#8217;s body cavity.
In this report, we provide an overview of our larval RNAi technique in T. castaneum. The protocol includes (i) isolation of the proper stage of T. castaneum larvae for injection, (ii) preparation for the injection setting, and (iii) dsRNA injection. Larval RNAi is a simple, but powerful technique that provides us with quick access to loss-of-function phenotypes, including multiple gene knockdown phenotypes as well as a series of hypomorphic phenotypes. Since virtually all T. castaneum tissues are susceptible to extracellular dsRNA, the larval RNAi technique allows researchers to study a wide variety of tissues in diverse contexts, including the genetic basis of organismal responses to the outside environment. In addition, the simplicity of this technique stimulates more student involvement in research, making T. castaneum an ideal genetic system for use in a classroom setting.

Larval RNA Interference in the Red Flour Beetle, Tribolium castaneum

RNA interference (RNAi)-based gene knockdown techniques are at the core of Tribolium research. Here, we provide an overview of our larval RNAi technique in Tribolium castaneum. Larval RNAi is a simple, but powerful technique that provides quick access to loss-of-function phenotypes, allowing researchers to study gene functions in diverse contexts.

The red flour beetle, Tribolium&#160;castaneum, offers a repertoire of experimental tools for genetic and developmental studies, including a fully ...

Production of Double-stranded DNA Ministrings

We constructed linear covalently closed (LCC) DNA minivectors as a non-viral gene-delivery vector alternative produced via a simple platform in vivo. DNA ministrings possess a heightened safety profile and also efficiently deliver DNA cargo to targeted cells. Conventional DNA vectors carry undesirable prokaryotic sequences, including antibiotic resistance genes, CpG motifs, and bacterial origins of replication, which may lead to the stimulation of host immunological responses. The bioavailability of conventional DNA vectors is also compromised due to their larger molecular size. Their circular nature may also impart chromosomal integration, leading to insertional mutagenesis.
Bacterial sequences are excised from DNA minivectors, leaving only the gene of interest (GOI) and necessary eukaryotic expression elements. Our LCC DNA minivectors, or DNA ministrings, are devoid of immunogenic bacterial sequences; therefore improving their bioavailability and GOI expression. In the event of vector integration into the chromosome, the LCC DNA ministring will lethally disrupt the host chromosome, thereby removing the potentially dangerous mutant from the proliferating cell population. Consequently, DNA ministrings offer the benefits of &#39;minicircle&#39; DNA while eliminating the potential for undesirable vector integration events. In comparison to conventional plasmids and their isogenic circular covalently closed (CCC) counterparts, DNA ministrings demonstrate superior bioavailability, transfection efficiency, and cytoplasmic kinetics - they thus require lower amounts of cationic surfactants for effective transfection of target cells.
We have constructed a one-step inducible in vivo system for the production of DNA ministrings in Escherichia coli that is simple to use, rapid, and scalable.

The linear covalently closed (LCC) DNA minivector (DNA ministring) is a non-viral gene delivery vector offering high transfection efficiency and is relevant to any DNA delivery application. The production system is simple, rapid, and scalable in vivo. The following protocol provides visual step-by-step instructions for the production of DNA ministrings.

We constructed linear covalently closed (LCC) DNA minivectors as a non-viral gene-delivery vector alternative produced via a simple platform in vivo. DNA ...

TChIP-Seq: Cell-Type-Specific Epigenome Profiling

Epigenetic regulation plays central roles in gene expression. Since histone modification was discovered in the 1960s, its physiological and pathological functions have been extensively studied. Indeed, the advent of next-generation deep sequencing and chromatin immunoprecipitation (ChIP) via specific histone modification antibodies has revolutionized our view of epigenetic regulation across the genome. Conversely, tissues typically consist of diverse cell types, and their complex mixture poses analytic challenges to investigating the epigenome in a particular cell type. To address the cell type-specific chromatin state in a genome-wide manner, we recently developed tandem chromatin immunoprecipitation sequencing (tChIP-Seq), which is based on the selective purification of chromatin by tagged core histone proteins from cell types of interest, followed by ChIP-Seq. The goal of this protocol is the introduction of best practices of tChIP-Seq. This technique provides a versatile tool for tissue-specific epigenome investigation in diverse histone modifications and model organisms.

We describe a step-by-step protocol for tandem chromatin immunoprecipitation sequencing (tChIP-Seq) that enables the analysis of cell-type-specific genome-wide histone modification.

Epigenetic regulation plays central roles in gene expression. Since histone modification was discovered in the 1960s, its physiological and pathological ...

Effective Oral RNA Interference (RNAi) Administration to Adult Anopheles gambiae Mosquitoes

RNA interference has been a heavily utilized tool for reverse genetic analysis for two decades. In adult mosquitoes, double-stranded RNA (dsRNA) administration has been accomplished primarily via injection, which requires significant time and is not suitable for field applications. To overcome these limitations, here we present a more efficient method for robust activation of RNAi by oral delivery of dsRNA to adult Anopheles gambiae. Long dsRNAs were produced in Escherichia coli strain HT115 (DE3), and a concentrated suspension of heat-killed dsRNA-containing bacteria in 10% sucrose was offered on cotton balls ad-libitum to adult mosquitoes. Cotton balls were replaced every 2 days for the duration of the treatment. Use of this method to target doublesex (a gene involved in sex differentiation) or fork head (which encodes a salivary gland transcription factor) resulted in reduced target gene expression and/or protein immunofluorescence signal, as measured by quantitative Real-Time PCR (qRT-PCR) or fluorescence confocal microscopy, respectively. Defects in salivary gland morphology were also observed. This highly flexible, user-friendly, low-cost, time-efficient method of dsRNA delivery could be broadly applicable to target genes important for insect vector physiology and beyond.

Effective Oral RNA Interference RNAi Administration to Adult Anopheles gambiae Mosquitoes

The oral administration of dsRNA produced by bacteria, a delivery method for RNA interference (RNAi) that is routinely used in Caenorhabditis elegans, was successfully applied here to adult mosquitoes. Our method allows for robust reverse genetics studies and transmission-blocking vector studies without the use of injection.