This work was supported in part by UCSD startup funds directed to O.S.A. and NSF/BIO grant 1645331 to J.L.R.

1. Nasonia rearing
<ol>
	<li>Set up ~20 mated females singularly in small glass test tubes plugged with cotton. 
	NOTE: To reduce rearing space, 10 x 85 cm, 4 mL tubes are optimal. Females are easily distinguished from males because of the larger wings and the presence of the ovipositor (Figure 1A). Detailed protocols for rearing N. vitripennis can also be found in other literature13,14,15...

<ol>
	<li>Verhulst, E. C., Beukeboom, L. W., van de Zande, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Maternal+control+of+haplodiploid+sex+determination+in+the+wasp+Nasonia.">Maternal control of haplodiploid sex determination in the wasp Nasonia.</a> Science. 328 (5978), 620-623 (2010).</li><li>Verhulst, E. C., Lynch, J. A., Bopp, D., Beukeboom, L. W., van de Zande, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+new+component+of+the+Nasonia+sex+determining+cascade+is+maternally+silenced+and+regulates+transformer+expression.">A new component of the Nasonia sex determining cascade is maternally silenced and regulates transformer expression.</a> PloS One. 8 (5), 63618 (2013).</li><li>Dalla Benetta, E., 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=Genome+elimination+mediated+by+gene+expression+from+a+selfish+chromosome.">Genome elimination mediated by gene expression from a selfish chromosome.</a> Science Advances. 6 (14), (2020).</li><li>Aldrich, J. C., Leibholz, A., Cheema, M. S., Ausi&#972;, J., Ferree, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+"selfish"+B+chromosome+induces+genome+elimination+by+disrupting+the+histone+code+in+the+jewel+wasp+Nasonia+vitripennis.">A "selfish" B chromosome induces genome elimination by disrupting the histone code in the jewel wasp Nasonia vitripennis.</a> Scientific Reports. 7, 42551 (2017).</li><li>Ferree, P. M., 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+of+genes+uniquely+expressed+in+the+germ-line+tissues+of+the+jewel+wasp+Nasonnia+vitripennis.">Identification of genes uniquely expressed in the germ-line tissues of the jewel wasp Nasonnia vitripennis.</a> G3. 3 (12), 2647-2653 (2015).</li><li>Akbari, O. S., Antoshechkin, I., Hay, B. A., Ferree, P. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Transcriptome+profiling+of+Nasonia+vitripennis+testis+reveals+novel+transcripts+expressed+from+the+selfish+B+chromosome,+paternal+sex+ratio.">Transcriptome profiling of Nasonia vitripennis testis reveals novel transcripts expressed from the selfish B chromosome, paternal sex ratio.</a> G3. 3 (9), 1597-1605 (2013).</li><li>Dalla Benetta, E., Beukeboom, L. W., van de Zande, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adaptive+differences+in+circadian+clock+gene+expression+patterns+and+photoperiodic+diapause+induction+in+Nasonia+vitripennis.">Adaptive differences in circadian clock gene expression patterns and photoperiodic diapause induction in Nasonia vitripennis.</a> The American Naturalist. 193 (6), 881-896 (2019).</li><li>Paolucci, S., 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=Latitudinal+variation+in+circadian+rhythmicity+in+Nasonia+vitripennis.">Latitudinal variation in circadian rhythmicity in Nasonia vitripennis.</a> Behavioral Sciences. 9 (11), (2019).</li><li>Werren, J. H., Loehlin, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+parasitoid+wasp+Nasonia:+an+emerging+model+system+with+haploid+male+genetics.">The parasitoid wasp Nasonia: an emerging model system with haploid male genetics.</a> Cold Spring Harbor Protocols. 2009 (10), (2009).</li><li>Lynch, J. A., Desplan, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+method+for+parental+RNA+interference+in+the+wasp+Nasonia+vitripennis.">A method for parental RNA interference in the wasp Nasonia vitripennis.</a> Nature Protocols. 1 (1), 486-494 (2006).</li><li>Li, M., 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=Generation+of+heritable+germline+mutations+in+the+jewel+wasp+Nasonia+vitripennis+using+CRISPR/Cas9.">Generation of heritable germline mutations in the jewel wasp Nasonia vitripennis using CRISPR/Cas9.</a> Scientific Reports. 7 (1), 901 (2017).</li><li>Chaverra-Rodriguez, D., 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=Germline+mutagenesis+of+Nasonia+vitripennis+through+ovarian+delivery+of+CRISPR-Cas9+ribonucleoprotein.">Germline mutagenesis of Nasonia vitripennis through ovarian delivery of CRISPR-Cas9 ribonucleoprotein.</a> Insect Molecular Biology. , (2020).</li><li>Li, M., Bui, M., Akbari, O. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Embryo+microinjection+and+transplantation+technique+for+Nasonia+vitripennis+genome+manipulation.">Embryo microinjection and transplantation technique for Nasonia vitripennis genome manipulation.</a> Journal of Visualized Experiments. (130), (2017).</li><li>Werren, J. H., Loehlin, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rearing+Sarcophaga+bullata+fly+hosts+for+Nasonia+(Parasitoid+Wasp).">Rearing Sarcophaga bullata fly hosts for Nasonia (Parasitoid Wasp).</a> Cold Spring Harbor Protocols. 2009 (10), (2009).</li><li>Werren, J. H., Loehlin, D. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Strain+maintenance+of+Nasonia+vitripennis+(Parasitoid+Wasp).">Strain maintenance of Nasonia vitripennis (Parasitoid Wasp).</a> Cold Spring Harbor Protocols. 2009 (10), (2009).</li><li>Beukeboom, L. W., van de Zande, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genetics+of+sex+determination+in+the+haplodiploid+wasp+Nasonia+vitripennis+(Hymenoptera:+Chalcidoidea).">Genetics of sex determination in the haplodiploid wasp Nasonia vitripennis (Hymenoptera: Chalcidoidea).</a> Journal of Genetics. 89 (3), 333-339 (2010).</li><li>Leung, K., van de Zande, L., Beukeboom, L. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Life-history+traits+of+the+Whiting+polyploid+line+of+the+parasitoid.">Life-history traits of the Whiting polyploid line of the parasitoid.</a> Entomologia experimentalis et applicata. 167 (7), 655-669 (2019).</li><li>Kennerdell, J. R., Carthew, R. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Use+of+dsRNA-mediated+genetic+interference+to+demonstrate+that+frizzled+and+frizzled+2+act+in+the+wingless+pathway.">Use of dsRNA-mediated genetic interference to demonstrate that frizzled and frizzled 2 act in the wingless pathway.</a> Cell. 95 (7), 1017-1026 (1998).</li><li>Yang, J., Zhao-jun, H. A. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Efficiency+of+different+methods+for+dsrna+delivery+in+cotton+bollworm+(Helicoverpa+armigera).">Efficiency of different methods for dsrna delivery in cotton bollworm (Helicoverpa armigera).</a> Journal of Integrative Agriculture. 13 (1), 115-123 (2014).</li><li>Brown, S., Holtzman, S., Kaufman, T., Denell, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+the+Tribolium+Deformed+ortholog+and+its+ability+to+directly+regulate+Deformed+target+genes+in+the+rescue+of+a+Drosophila+Deformed+null+mutant.">Characterization of the Tribolium Deformed ortholog and its ability to directly regulate Deformed target genes in the rescue of a Drosophila Deformed null mutant.</a> Development Genes and Evolution. 209 (7), 389-398 (1999).</li><li>Hughes, C. L., Kaufman, T. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=RNAi+analysis+of+Deformed,+proboscipedia+and+Sex+combs+reduced+in+the+milkweed+bug+Oncopeltus+fasciatus:+novel+roles+for+Hox+genes+in+the+hemipteran+head.">RNAi analysis of Deformed, proboscipedia and Sex combs reduced in the milkweed bug Oncopeltus fasciatus: novel roles for Hox genes in the hemipteran head.</a> Development. 127 (17), 3683-3694 (2000).</li><li>Dzitoyeva, S., Dimitrijevic, N., Manev, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intra-abdominal+injection+of+double-stranded+RNA+into+anesthetized+adult+Drosophila+triggers+RNA+interference+in+the+central+nervous+system.">Intra-abdominal injection of double-stranded RNA into anesthetized adult Drosophila triggers RNA interference in the central nervous system.</a> Molecular Psychiatry. 6 (6), 665-670 (2001).</li><li>Chaverra-Rodriguez, D., 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=Targeted+delivery+of+CRISPR-Cas9+ribonucleoprotein+into+arthropod+ovaries+for+heritable+germline+gene+editing.">Targeted delivery of CRISPR-Cas9 ribonucleoprotein into arthropod ovaries for heritable germline gene editing.</a> Nature Communications. 9 (1), 3008 (2018).</li><li>Macias, V. M., 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=Cas9-mediated+gene-editing+in+the+malaria+mosquito+anopheles+stephensi+by+ReMOT+control.">Cas9-mediated gene-editing in the malaria mosquito anopheles stephensi by ReMOT control.</a> G3. 10 (4), 1353-1360 (2020).</li><li>Heu, C. C., McCullough, F. M., Luan, J., Rasgon, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=CRISPR/Cas9-based+genome+editing+in+the+silverleaf+whitefly+(Bemisia+tabaci).">CRISPR/Cas9-based genome editing in the silverleaf whitefly (Bemisia tabaci).</a> CRISPR Journal. 3 (2), 89-96 (2020).</li><li>Shirai, Y., Daimon, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mutations+in+cardinal+are+responsible+for+the+red-1+and+peach+eye+color+mutants+of+the+red+flour+beetle+Tribolium+castaneum.">Mutations in cardinal are responsible for the red-1 and peach eye color mutants of the red flour beetle Tribolium castaneum.</a> Biochemical and Biophysical Research Communications. 529 (2), 372-378 (2020).</li><li>Hunter, W. B., Gonzalez, M. T., Tomich, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=BAPC-assisted+CRISPR/Cas9+system:+targeted+delivery+into+adult+ovaries+for+heritable+germline+gene+editing+(Arthropoda:+Hemiptera).">BAPC-assisted CRISPR/Cas9 system: targeted delivery into adult ovaries for heritable germline gene editing (Arthropoda: Hemiptera).</a> bioRxiv. , 478743 (2018).</li><li>Chaverra Rodriguez, D., Bui, M., Li, M., Raban, R., Akbari, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Developing+genetic+tools+to+control+ACP.">Developing genetic tools to control ACP.</a> Citrus Research Board Citrograph Magazine. 11 (1), 64-68 (2020).</li></ol>

With the recent increased use of Nasonia vitripennis as a model organism for various biological questions2,3,7,17, there is a need to develop and optimize injection methods to enable a simplified and efficient protocol for the functional analysis of N. vitripennis genes. The current methods involving embryonic microinjection of gene editing reagents are challenging<sup class="...

CRISPR/Cas9 gene editing is a powerful technology for functional genetic studies, especially in many rising model organisms such as the jewel wasp, Nasonia vitripennis. The ease of rearing and the availability of a complete genome makes the jewel wasp an important experimental system for elucidating the molecular mechanisms of different biological processes. For example, N. vitripennis has recently been used to unravel the epigenetic basis of the haplodiploid sex determination system1,2, the biology of B-chromosomes3,4,5,6, and the genetic basis for circadian and seasonal regulation7,8. Some of the features that make N. vitripennis amenable to work with include short generation time (~2 weeks at 25 &#176;C), high reproduction rates, easy sex separation at the pupal stage, and the ability to diapause and store strains at 4 &#176;C. The life cycle begins with female wasps parasitizing the pupae of the blowfly, Sarcophaga bullata. Through their ovipositor, females lay up to 50 eggs in the pupal case of the blowfly. Eggs develop into larvae that feed on the S. bullata pupa, continue to develop over the next several days, and then pupate, followed by adult eclosion and emergence from the host puparium9.
Molecular tools to perform functional genetic studies in N. vitripennis, such as RNA interference (RNAi)10 and CRISPR/Cas911,12, are available, but are limited, primarily due to difficulties in performing embryonic microinjections13. As N. vitripennis eggs require a pupal host for development, egg manipulation is very challenging. Pre-blastoderm stage embryos must be collected from the host blowfly pupae, quickly microinjected, and immediately transferred back to the host for development13. These steps require precision and specialized training to avoid damaging the microinjected embryos or the pupal hosts13. Moreover, the eggs are very small and fragile, especially after microinjections, with a very viscous cytoplasm causing a continuous clogging of the injecting needle13. These features make embryonic microinjections exceptionally challenging, requiring highly trained operators and specialized equipment that is absent in most N. vitripennis laboratories.
The optimization of alternative injection methods for the delivery of CRISPR reagents would contribute to the consolidation of N. vitripennis as a model organism. The manipulation of pupae and adults is less challenging than manipulating embryos and can be accomplished with a basic injection setup. Here, two protocols are described for injection of pupae and adults: one involving specialized equipment for injections, and the other involving the use of an aspirator tube assembly fitted with a glass capillary needle. The use of an aspirator tube is particularly suited for laboratories that do not have access to specialized equipment for embryo microinjections. Efficient injections of different developmental stages of N. vitripennis, including white or black pupae and adult wasps, are demonstrated. Wasps at the white pupal stage are particularly suited for RNAi-mediated knockdown experiments. Although RNAi in Nasonia was first described by Lynch and Desplan in 200610, there is no visual procedure available for how RNAi injections are performed. RNAi was recently used to discover the haploidizer gene of the B-chromosome PSR (Paternal Sex Ratio)3 and to study the involvement of the clock gene, period, in N. vitripennis biological rhythms7.
Black pupae and adult wasps can be used to induce CRISPR/Cas9 germline gene editing using ReMOT Control (Receptor-Mediated Ovary Transduction of Cargo) and BAPC (Branched Amphiphilic Peptide Capsules) protocols. These two ovary delivery methods have been recently described to be effective in Nasonia for generating germline mutations in the target gene, cinnabar7,12. Here, a simplified protocol is provided for injections including a visual procedure of a step-by-step methodology for both pupal and adult injections that can be utilized to generate functional genetics studies in Nasonia and likely in other parasitoid wasps, without requiring specialized equipment and bypassing embryonic microinjections.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>100 x 15 mm Stackable Petri Dishes, Polystyrene, Mono, Sterile</td>
			<td>Sigma</td>
			<td>960-97693-083</td>
			<td></td>
		</tr>
		<tr>
			<td>Aluminosilicate glass capillary tubing 1 mm(outside diameter) x 0.58 mm (inner diameter)</td>
			<td>Sutter Instruments</td>
			<td>BF100-58-10</td>
			<td>Can also use Borosilicate or Quartz</td>
		</tr>
		<tr>
			<td>Aspirator tube assemblies for calibrated microcapillary pipettes</td>
			<td>Sigma</td>
			<td>A5177-5EA</td>
			<td></td>
		</tr>
		<tr>
			<td>BAPC</td>
			<td>phoreus biotech</td>
			<td>BAPtofect-25 0.5 mg Kit</td>
			<td></td>
		</tr>
		<tr>
			<td>Cas9 Protein with NLS</td>
			<td>PNABio</td>
			<td>CP01</td>
			<td></td>
		</tr>
		<tr>
			<td>Dissecting needle</td>
			<td>VWR</td>
			<td>10806-330</td>
			<td></td>
		</tr>
		<tr>
			<td>DNase/RNase-Free distilled Water</td>
			<td>Invitrogen</td>
			<td>10977-015</td>
			<td></td>
		</tr>
		<tr>
			<td>Femtojet Express programmable microinjector</td>
			<td>Eppendorf</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Femtotips Microloader tips</td>
			<td>Fisher Scientific</td>
			<td>E5242956003</td>
			<td></td>
		</tr>
		<tr>
			<td>Fine-tip paintbrush</td>
			<td>ZEM</td>
			<td>2595</td>
			<td></td>
		</tr>
		<tr>
			<td>Flesh fly pupae,&#160;Sarcophaga bullata</td>
			<td>Ward&#39;s Science</td>
			<td>470180-392</td>
			<td></td>
		</tr>
		<tr>
			<td>Food colorant dye</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Glass Test Tubes</td>
			<td>Fisher Scientific</td>
			<td>982010</td>
			<td></td>
		</tr>
		<tr>
			<td>Glue</td>
			<td>Elmer&#39;s</td>
			<td></td>
			<td>washable, no toxic school glue</td>
		</tr>
		<tr>
			<td>Micropipette Puller</td>
			<td>Sutter Instruments</td>
			<td>P-1000 or P-2000</td>
			<td></td>
		</tr>
		<tr>
			<td>Microscope Slides</td>
			<td>Fisherbrand</td>
			<td>12-550-A3</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereo Microscope</td>
			<td>Olympus</td>
			<td>SZ51</td>
			<td></td>
		</tr>
	</tbody>
</table>

pupal and adult injections for rnai and crispr gene editing in nasonia vitripennis

The jewel wasp, Nasonia vitripennis, has become an efficient model system to study epigenetics of haplo-diploid sex determination, B-chromosome biology, host-symbiont interactions, speciation, and venom synthesis. Despite the availability of several molecular tools, including CRISPR/Cas9, functional genetic studies are still limited in this organism. The major limitation of applying CRISPR/Cas9 technology in N. vitripennis stems from the challenges of embryonic microinjections. Injections of embryos are particularly difficult in this organism and in general in many parasitoid wasps, due to small embryo size and the requirement of a host pupa for embryonic development. To address these challenges, Cas9 ribonucleoprotein complex delivery into female&#160;ovaries by adult injection, rather than embryonic microinjection, was optimized, resulting in both somatic and heritable germline edits. The injection procedures were optimized in pupae and female wasps using either ReMOT Control (Receptor-Mediated Ovary Transduction of Cargo) or BAPC (Branched Amphiphilic Peptide Capsules). These methods are shown to be effective alternatives to embryo injection, enabling site-specific and heritable germline mutations.

This paper presents two easy methods for pupal and adult microinjection, either using a femtojet or an aspirator tube. The first method allows a more precise injection of liquid, which is important for RNAi consistency, whereas the second one allows the injection of larger amounts of liquid into Nasonia pupae or adults.
Representative results presented in Table 1 show good survival rates (from 20% to 89...

Watch this Scientific Journal Video about Pupal and Adult Injections for RNAi and CRISPR Gene Editing in Nasonia vitripennis at JoVE.com

Pupal and Adult Injections for RNAi and CRISPR Gene Editing in Nasonia vitripennis

Here, we describe methods for efficient pupal and adult injections in Nasonia vitripennis as accessible alternatives to embryo microinjection, enabling functional analysis of genes of interest using either RNA-silencing via RNA interference (RNAi) or gene knockout via CRISPR/Cas9 genome editing.

Pupal and Adult Injections for RNAi and CRISPR Gene Editing in Nasonia vitripennis

The jewel wasp, Nasonia vitripennis, has become an efficient model system to study epigenetics of haplo-diploid sex determination, B-chromosome biology, ...

Research on non-canonical insect model, like parasitoid wasp, is limited because embryonic microinjection is very challenging. Our method bypasses this problem, enabling site-specific and heritable germline mutations. Injecting pupae or adult females is fast and removes the requirement for expensive equipment or specialized training required to achieve successful embryonic microinjections.This technique will allow no specialized labs that do not have access to expensive equipment to do functional studies in any insect species they are using as a model. After the optimization, this method can be used to study functional genetics of many other genes in Nasonia. We also think this method may be used to deliver nucleic acids for genetic transformation of Nasonia or other insects.Begin by setting up approximately 20 mated females singularly in small glass test tubes plugged with cotton. Add two S.bullata hosts per tube and maintain the wasps at 25 degrees Celsius and 30%relative humidity with a 12:12 light dark cycle for two to three days. After two to three days, gently remove the females using a fine tipped brush to avoid continuous over position and a synchrony in offspring development.Removed females can optionally be re-hosted or stored at five degrees Celsius for up to a month. Maintain the parasitized host at 25 degrees Celsius and 30%relative humidity with a 12:12 light dark cycle for seven days if the desired injection stage requires white pupae, for 13 days, if the required developmental stage is black pupae, or 14 days for young, newly emerged adults. When the desired stage is reached, crack open the host puparium with a dissecting needle to recover N.vitripennis pupae and adults.Prepare a glass slide by applying a line of school glue at the center. Spread the glue with the dissecting needle to obtain a thick layer, which will be used to align the pupae. Let the glue dry for approximately two minutes before transferring the pupae.Under a dissecting microscope, use a dissecting needle to apply glue on the back of the head of the pupa. Attach the pupa to the glue layer on the slide with its abdomen facing up. Align 20 to 30 pupae side-by-side on the slide.Place the slide with the pupae and a Petri dish to let the glue drive for approximately 10 minutes. Before starting the injections, test the adherence of the pupae to the glue by pushing them gently with the dissecting needle. If most of the pupae are loosened, prepare a new slide.Alternatively, remove all loose pupae and proceed to inject those that are properly attached to the slide. Load one capillary glass tube into a needle puller and pull needles following the manufacturer's instructions. Load the needle with five microliters of the prepared injection mixture using microloader pipette tips.Open the needle, sliding the tip on a surface made from two overlapping slides. Alternatively, open the tip of the needle with a pair of fine forceps to create a sharp edge. Place the slide with the aligned pupae under a dissecting microscope, then insert the needle into the femtojet's injection tube and tighten the grip head.Looking at the needle under the microscope, turn on the femtojet and set the compensation pressure and injection pressure parameters by rotating the rotary knobs. Carefully insert the needle between the second and third visible abdominal segments with a vertical angle of about 30 degrees. Inject with a continuous flow until the whole abdomen turns green in the case of white stage pupae or until the abdomen increases in size in the case of black pupae.Stop injecting when it is clear that the abdomen cannot take any more liquid or when the liquid starts flowing out of the body. Move carefully to the next pupa and repeat these steps. Transfer the slide with the injected pupae to a Petri dish.Cover the dish with its lid and place it at 25 degrees Celsius until wasp emergence. For adult preparation, separate groups of 20 virgin females in a clean small test tube with a fine paint brush. Place a glass slide on top of ice and align the female side by side on the cold slide with abdomens facing up under a dissecting scope.Load one needle with the ribonucleoprotein solution using a microloading tip and insert the needle into the connector pack of the aspirator tube assembly. Support the females from the opposite side with blunted dissecting needles, while injecting slowly into the abdomen. Avoid touching the ovipositor.This will severely damage this critical reproductive structure. Carefully insert the needle between the second and third visible abdominal segments with a vertical angle of about 30 degrees. Inject the solution into the female abdomen, stopping when no more liquid can enter or when leaking of surplus solution is observed.Move carefully to the next female and repeat these steps. When finished, gently transfer a single injected females to a new tube with one host using a paintbrush. Leave them to recover at room temperature for approximately one hour, confirm survival, and return the tubes to the rearing incubator.After adult eclosion from the injected pupae, place single wasps into a glass to plugged with cotton and insert one S.bullata host. For CRISPR/Cas9 knockout experiments, allow females to parasitize the host for one day and replace the host each day for three consecutive days. Place the parasitized host, set 25 degrees Celsius until emergence of the G0 male offspring, approximately 13 to 14 days.Under a dissecting microscope, screen G0 males for the mutated phenotypes. The cinnabar gene is responsible for eye pigmentation. Wasps with brown eyes are wild-type and wasps with bright red eyes or variations between red and brown eyes are mutants.This protocol can be used for either pupal or adult microinjection. Survival rates of this procedure range from 15 to 100%The efficiency of achieving the desired phenotype via RNAi or CRISPR without requiring laborious egg injections is shown here. When injecting pupae or adult females, the needle should be sharp and be introduced in a way that liquid should not leak immediately after injecting.If this happens, remove the needle, ensure that the tip is fine and sharp, change it if necessary or inject in a different location. Function analysis can be performed on the gene of interest targeted from this procedure. This will answer a question about the gene function and if the gene is necessary for the specific phenotype studied.

pupal-adult-injections-for-rnai-crispr-gene-editing-nasonia

Research

JoVE Journal

Biology

5.0K visualizações.  University of California, San Diego. Research on non-canonical insect model, like parasitoid wasp, is limited because embryonic microinjection is very challenging. Our method bypasses this problem, enabling site-specific and heritable germline mutations. Injecting pupae or adult females is fast and removes the requirement for expensive equipment or specialized training required to achieve successful embryonic microinjections.This technique will allow no specialized labs that do not have access to expensive equipment to do...