Name: using the gal4-uas system for functional genetics in anopheles gambiae
Uploaded: 2021-04-15T13:00:00
Description: Watch this Scientific Journal Video about Using the GAL4-UAS System for Functional Genetics in Anopheles gambiae at JoVE.com

We gratefully acknowledge funding from LSTM and IVCC (Adriana Adolfi), BBSRC (New Investigator Award (AL), MRC (PhD studentship to BCP:MR/P016197/1), Wellcome (Sir Henry Wellcome Postdoctoral fellowship to LG: 215894/Z/19/Z) that have incorporated Gal4UAS analysis in the proposals.

1.&#160;Design and construction of UAS constructs
<ol>
	<li>Design and assembly of vectors for candidate gene expression
	<ol>
		<li>Determine the sequence to be used for candidate gene upregulation.
		<ol>
			<li>Sequence the cDNA/gDNA from the strain of interest and compare it to the published sequence to verify its identity and identify potential SNPs and restriction sites for diagnostic digest.</li>
			<li>Ensure that the forward primer used for gene amplification covers the native...

<ol>
	<li>Brand, A. H., Perimon, N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeted+gene+expression+as+a+means+of+altering+cell+fates+and+generating+dominant+phenotypes.">Targeted gene expression as a means of altering cell fates and generating dominant phenotypes.</a> Development. 118 (2), 401-415 (1993).</li><li>Duffy, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=GAL4+system+in+drosophila:+A+fly+geneticist's+swiss+army+knife.">GAL4 system in drosophila: A fly geneticist's swiss army knife.</a> Journal of Genetics and Development. 34 (1-2), 1-15 (2002).</li><li>Dow, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> ELS. , (2012).</li><li>Edi, C. V., 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=CYP6+P450+Enzymes+and+ACE-1+Duplication+Produce+Extreme+and+Multiple+Insecticide+Resistance+in+the+Malaria+Mosquito+Anopheles+gambiae.">CYP6 P450 Enzymes and ACE-1 Duplication Produce Extreme and Multiple Insecticide Resistance in the Malaria Mosquito Anopheles gambiae.</a> PLoS Genetics. 10 (3), 1004236 (2014).</li><li>Daborn, P. 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=Using+Drosophila+melanogaster+to+validate+metabolism-based+insecticide+resistance+from+insect+pests.">Using Drosophila melanogaster to validate metabolism-based insecticide resistance from insect pests.</a> Insect Biochemistry and Molecular Biology. 42 (12), 918-924 (2012).</li><li>Riveron, J. 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=Genome-wide+transcription+and+functional+analyses+reveal+heterogeneous+molecular+mechanisms+driving+pyrethroids+resistance+in+the+major+malaria+vector+Anopheles+funestus+across+Africa.">Genome-wide transcription and functional analyses reveal heterogeneous molecular mechanisms driving pyrethroids resistance in the major malaria vector Anopheles funestus across Africa.</a> Genes Genomes Genetics. 7 (6), 1819-1832 (2017).</li><li>Riveron, J. 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=A+single+mutation+in+the+GSTe2+gene+allows+tracking+of+metabolically+based+insecticide+resistance+in+a+major+malaria+vector.">A single mutation in the GSTe2 gene allows tracking of metabolically based insecticide resistance in a major malaria vector.</a> Genome Biology. 15 (2), (2014).</li><li>Lynd, A., Lycett, G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+the+Bi-Partite+Gal4-UAS+System+in+the+African+Malaria+Mosquito,+Anopheles+gambiae.">Development of the Bi-Partite Gal4-UAS System in the African Malaria Mosquito, Anopheles gambiae.</a> PLoS ONE. 7 (2), 31552 (2012).</li><li>Lynd, A., Lycett, G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Optimization+of+the+Gal4-UAS+system+in+an+Anopheles+gambiae+cell+line.">Optimization of the Gal4-UAS system in an Anopheles gambiae cell line.</a> Insect Molecular Biology. 20 (5), 599-608 (2011).</li><li>Adolfi, A., Pondeville, E., Lynd, A., Bourgouin, C., Lycett, G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multi-tissue+GAL4-mediated+gene+expression+in+all+Anopheles+gambiae+life+stages+using+an+endogenous+polyubiquitin+promoter.">Multi-tissue GAL4-mediated gene expression in all Anopheles gambiae life stages using an endogenous polyubiquitin promoter.</a> Insect Biochemistry and Molecular Biology. 96, 1-9 (2018).</li><li>Kokoza, V. A., Raikhel, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Targeted+gene+expression+in+the+transgenic+Aedes+aegypti+using+the+binary+Gal4-UAS+system.">Targeted gene expression in the transgenic Aedes aegypti using the binary Gal4-UAS system.</a> Insect Biochemistry and Molecular Biology. 41, 637-644 (2011).</li><li>O'Brochta, D. A., Pilitt, K. L., Harrell, R. A., Aluvihare, C., Alford, R. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gal4-based+Enhancer-Trapping+in+the+Malaria+Mosquito+Anopheles+stephensi.">Gal4-based Enhancer-Trapping in the Malaria Mosquito Anopheles stephensi.</a> Genes Genomes Genetics. 2, 21305-21315 (2012).</li><li>Zhao, B., 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=Regulation+of+the+Gut-Specific+Carboxypeptidase:+A+Study+Using+the+Binary+Gal4/UAS+System+in+the+Mosquito+Aedes+Aegypti.">Regulation of the Gut-Specific Carboxypeptidase: A Study Using the Binary Gal4/UAS System in the Mosquito Aedes Aegypti.</a> Insect Biochemistry and Molecular Biology. 54, 1-10 (2014).</li><li>Imamura, 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=Targeted+Gene+Expression+Using+the+GAL4/UAS+System+in+the+Silkworm+Bombyx+mori.">Targeted Gene Expression Using the GAL4/UAS System in the Silkworm Bombyx mori.</a> Genetics. 165 (3), 1329-1340 (2003).</li><li>Lynd, A., 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=Development+of+a+functional+genetic+tool+for+Anopheles+gambiae+oenocyte+characterisation:+application+to+cuticular+hydrocarbon+synthesis.">Development of a functional genetic tool for Anopheles gambiae oenocyte characterisation: application to cuticular hydrocarbon synthesis.</a> bioRxiv. , (2019).</li><li>Pondeville, 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=Hemocyte-targeted+gene+expression+in+the+female+malaria+mosquito+using+the+hemolectin+promoter+from+Drosophila.">Hemocyte-targeted gene expression in the female malaria mosquito using the hemolectin promoter from Drosophila.</a> Insect Biochemistry and Molecular Biology. 120, 103339 (2020).</li><li>Adolfi, A., 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=Functional+genetic+validation+of+key+genes+conferring+insecticide+resistance+in+the+major+African+malaria+vector,+Anopheles+gambiae.">Functional genetic validation of key genes conferring insecticide resistance in the major African malaria vector, Anopheles gambiae.</a> Proceedings of the National Academy of Sciences of the United States of America. 116 (51), 25764-25772 (2019).</li><li>Pondeville, 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=Efficient+integrase-mediated+site-specific+germline+transformation+of+Anopheles+gambiae.">Efficient integrase-mediated site-specific germline transformation of Anopheles gambiae.</a> Nature Protocols. 9 (7), 1698-1712 (2014).</li><li>Horn, C., Schmid, B. G. M., Pogoda, F. S., Wimmer, E. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluorescent+transformation+markers+for+insect+transgenesis.">Fluorescent transformation markers for insect transgenesis.</a> Insect Biochemistry and Molecular Biology. 32, 1221-1235 (2002).</li><li>Clements, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> A. Biology of Mosquitoes, Volume 1: Development, Nutrition and Reproduction. 1, (1992).</li><li>Trpi&#353;, 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+new+bleaching+and+decalcifying+method+for+general+use+in+zoology.">A new bleaching and decalcifying method for general use in zoology.</a> Canadian Journal of Zoology. 48, 892-893 (1970).</li><li>Kaiser, M. L., Duncan, F. D., Brooke, B. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Embryonic+Development+and+Rates+of+Metabolic+Activity+in+Early+and+Late+Hatching+Eggs+of+the+Major+Malaria+Vector+Anopheles+gambiae.">Embryonic Development and Rates of Metabolic Activity in Early and Late Hatching Eggs of the Major Malaria Vector Anopheles gambiae.</a> PLoS ONE. 9 (12), 114381 (2014).</li><li>Grigoraki, L., Grau-Bov&#233;, X., Yates, H. C., Lycett, G. J., Ranson, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+transcriptomic+analysis+of+Anopheles+gambiae+oenocytes+enables+the+delineation+of+hydrocarbon+biosynthesis.">Isolation and transcriptomic analysis of Anopheles gambiae oenocytes enables the delineation of hydrocarbon biosynthesis.</a> eLife. 9, 58019 (2020).</li><li>Xiao, Y. -. H., Yin, M. -. H., Hou, L., Pei, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Direct+amplification+of+intron-containing+hairpin+RNA+construct+from+genomic+DNA.">Direct amplification of intron-containing hairpin RNA construct from genomic DNA.</a> BioTechniques. 41 (5), 548-552 (2006).</li><li>Livak, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organization+and+Mapping+of+a+Sequence+on+the+Drosophila+melanogaster+X+and+Y+Chromosomes+That+Is+Transcribed+during+Spermatogenesis.">Organization and Mapping of a Sequence on the Drosophila melanogaster X and Y Chromosomes That Is Transcribed during Spermatogenesis.</a> Genetics. 107 (4), 611-634 (1984).</li><li>MR4, CDC, NEI &amp; beiResources. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The MR4 Methods in Anopheles Research Laboratory Manual. 5th Edition. , (2015).</li><li>Sik Lee, Y., 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=Making+a+better+RNAi+vector+for+Drosophila:+use+of+intron+spacers.">Making a better RNAi vector for Drosophila: use of intron spacers.</a> Methods. 30 (4), 322-329 (2003).</li><li>Cha-aim, K., Hoshida, H., Fukunaga, T., Akada, R., Peccoud, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Gene Synthesis: Methods and Protocols. , 97-110 (2012).</li><li>Cavener, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comparison+of+the+consensus+sequence+flanking+translational+start+sites+in+Drosophila+and+vertebrates.">Comparison of the consensus sequence flanking translational start sites in Drosophila and vertebrates.</a> Nucleic Acids Research. 15 (4), 1353-1361 (1987).</li><li>Wang, Y., Wang, F., Wang, R., Zhao, P., Xia, Q. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=2A+self-cleaving+peptide-based+multi-gene+expression+system+in+the+silkworm+Bombyx+mori.">2A self-cleaving peptide-based multi-gene expression system in the silkworm Bombyx mori.</a> Scientific Reports. 5, (2015).</li><li>Galizi, R., 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=A+synthetic+sex+ratio+distortion+system+for+the+control+of+the+human+malaria+mosquito.">A synthetic sex ratio distortion system for the control of the human malaria mosquito.</a> Nature Communications. 5, 3977 (2014).</li><li>Kondo, 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=Neurochemical+organisation+of+the+Drosophila+Brain+Visualised+by+Endogenously+Tagged+Neurotransmitter+Receptors.">Neurochemical organisation of the Drosophila Brain Visualised by Endogenously Tagged Neurotransmitter Receptors.</a> Cell Reports. 30 (1), 284-297 (2020).</li><li>Lee, P. -. 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=A+gene-specific+T2A-GAL4+library+for+Drosophila.">A gene-specific T2A-GAL4 library for Drosophila.</a> eLife. 7, 35574 (2018).</li><li>Marois, 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=High-throughput+sorting+of+mosquito+larvae+for+laboratory+studies+and+for+future+vector+control+interventions.">High-throughput sorting of mosquito larvae for laboratory studies and for future vector control interventions.</a> Malaria Journal. 11, 302 (2012).</li><li>Crawford, J. 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=Efficient+production+of+male+Wolbachia-infected+Aedes+aegypti+mosquitoes+enables+large-scale+suppression+of+wild+populations.">Efficient production of male Wolbachia-infected Aedes aegypti mosquitoes enables large-scale suppression of wild populations.</a> Nature Biotechnology. 38 (4), 482-492 (2020).</li><li>Goltsev, 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=Developmental+and+evolutionary+basis+for+drought+tolerance+of+the+Anopheles+gambiae+embryo.">Developmental and evolutionary basis for drought tolerance of the Anopheles gambiae embryo.</a> Developmental Biology. 330 (2), 462-470 (2009).</li><li>Rezende, G. L., 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=Embryonic+desiccation+resistance+in+Aedes+aegypti:+presumptive+role+of+the+chitinized+Serosal+Cuticle.">Embryonic desiccation resistance in Aedes aegypti: presumptive role of the chitinized Serosal Cuticle.</a> BMC Developmental Biology. 8 (1), 82 (2008).</li><li>Vargas, H. C. M., Farnesi, L. C., Martins, A. J., Valle, D., Rezende, G. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Serosal+cuticle+formation+and+distinct+degrees+of+desiccation+resistance+in+embryos+of+the+mosquito+vectors+Aedes+aegypti,+Anopheles+aquasalis+and+Culex+quinquefasciatus.">Serosal cuticle formation and distinct degrees of desiccation resistance in embryos of the mosquito vectors Aedes aegypti, Anopheles aquasalis and Culex quinquefasciatus.</a> Journal of Insect Physiology. 62, 54-60 (2014).</li><li>Chang, C. -. H., 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=The+non-canonical+Notch+signaling+is+essential+for+the+control+of+fertility+in+Aedes+aegypti.">The non-canonical Notch signaling is essential for the control of fertility in Aedes aegypti.</a> PLOS Neglected Tropical Diseases. 12 (3), 0006307 (2018).</li><li>Clemons, A., Flannery, E., Kast, K., Severson, D., Duman-Scheel, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Immunohistochemical+Analysis+of+Protein+Expression+during+Aedes+aegypti+Development.">Immunohistochemical Analysis of Protein Expression during Aedes aegypti Development.</a> Spring Harbor Protocols. 10, 1-4 (2010).</li><li>Juhn, J., James, A. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hybridization+in+situ+of+Salivary+Glands,+Ovaries+and+Embryos+of+Vector+Mosquitoes.">Hybridization in situ of Salivary Glands, Ovaries and Embryos of Vector Mosquitoes.</a> Journal of Visualized Experiments. , e3709 (2012).</li></ol>

Understanding mosquito gene function is vital to develop new approaches to control&#160;Anopheles&#160;and impact malaria transmission. The GAL4-UAS system described is a versatile and powerful system for functional analysis of candidate genes and to date we have used the system to examine the genetic basis of insecticide resistance17&#160;and cuticular hydrocarbon production15,23, as well as to fluorescently tag different mosquit...

The bipartite GAL4-UAS system is the workhorse of functional characterization of genes in the insect model organism Drosophila melanogaster1,2,3. To use the GAL4-UAS system, transgenic driver lines, expressing the yeast transcription factor GAL4 under control of a regulatory sequence, are crossed with responder lines carrying a gene of interest or RNA interference (RNAi) construct controlled by an Upstream Activation Sequence (UAS) recognized by GAL4. The progeny of this cross express the transgene of interest in a spatiotemporal pattern dictated by the promoter controlling GAL4 expression (Figure 1). Phenotypes displayed by progeny of driver-responder crosses can be assessed to elucidate the function of candidate genes. Although D. melanogaster has been used to examine genes from other organisms4,5,6,7, the GAL4-UAS system has now been adapted for use in insects of medical and agricultural importance to provide direct analysis in the species of interest 8,9,10,11,12,13,14.
In the African malaria mosquito, Anopheles&#160;gambiae, the GAL4-UAS system was first tested by cell line co-transfection9. Multiple constructs were assayed for efficiency in different pairwise combinations and found that 14 tandemly repeated UAS supplemented with a small artificial intron (UAS-14i) displayed the widest range of activation potential when used with a panel of GAL4 drivers. To demonstrate in vivo functionality, these constructs were then used to create two separate transgenic An. gambiae lines by PiggyBac transformation8: a driver line carrying GAL4 driven by a midgut specific promoter, and a responder line containing both the luciferase and enhanced yellow fluorescent protein (eYFP) genes under regulation of UAS sequences. Gut specific luciferase activity and fluorescence in the progeny indicated that the system was efficient in Anopheles. Since then, driver lines have been created expressing transgenes in other tissues important for vectorial capacity and insecticide resistance, including oenocytes15 and hemocytes16, and in a close to ubiquitous pattern10. Numerous UAS lines have also been generated to assay genes thought to be involved in metabolism and sequestration mediated insecticide resistance, cuticular hydrocarbon synthesis and to fluorescently tag different cell and tissue types (Table 1). For the responder lines, site-directed integration of the transgene is now performed by &#934;C31 catalyzed recombination cassette exchange17,18 to fix the genomic context of the UAS regulated genes. In this way, transgene expression is normalized regarding genomic insertion location, allowing for more accurate comparison of the phenotypic effects of different candidate genes.
The responder lines created to date are designed to either express the transgene either at elevated levels or to reduce gene expression through RNA interference (RNAi). Usually cDNA clones are fused to the UAS sequence to generate suitable expression plasmids, however full genomic sequences are also feasible assuming that they are not too large for cloning. To generate silencing constructs, we have used three different methods to obtain suitable tandem inverted sequences that form hairpin dsRNA that stimulates RNAi. These have included fusion PCR, asymmetric PCR and commercial synthesis of hairpin constructs. Common to each method is the inclusion of an intron sequence between the inverted&#160;sequences to provide cloning stability. Responder plasmids into which a gene of interest/RNAi construct can be inserted have been developed15. These plasmids also carry the required &#934;C31 attB sites for RMCE (described in Adolfi accompanying JoVE paper which describes the RCME technique in detail). Protocols covering the important steps required when selecting the sequence for insertion into one of these plasmids for overexpression are included in this manuscript. Additionally, two protocols for RNAi hairpin construct creation are described and illustrated.
When creating new lines, identification of rare transgenic individuals is crucial to breed from to establish and maintain transgenic colonies. Most importantly for the GAL4-UAS system there is a necessity to distinguish the responder and driver lines to establish crosses and identify individual progeny that carry both transgenes. This is achieved by using different dominant selectable marker genes linked to the driver and responder cassettes. Most commonly these are fluorescent marker genes that are clearly distinguishable using optical filters (e.g., eYFP, eCFP, dsRed). It is important that markers are expressed in a known and reliable spatiotemporal pattern as this makes identification of abnormalities and contamination easier. Fluorescent marker gene expression is routinely regulated by the synthetic 3xP3 promoter, which causes eye and ventral ganglia specific expression in all stages of An. gambiae development19. Fluorescent markers controlled by 3xP3 are included in all transformation plasmids described in this article. A protocol detailing the common methods used to screen fluorescent An. gambiae pupae GAL4-UAS lines is included here.
One of the key elements of the GAL4-UAS system is the necessity to cross the differentially marked driver and responder lines. To do this male and females from each line must be separated prior to mating. Adults are readily distinguishable by sight, however, for establishing genetic crosses it is sensible to separate the sexes prior to adult emergence to ensure that mating has not occurred. The general size difference between male and female An. gambiae pupae is too variable to be an efficient and dependable method of sex determination20. Instead clear morphological differences in the external genitalia provide a reliable basis for sexing in An. gambiae. In this article, we describe a dependable method for sexing An. gambiae pupae to set up appropriate crosses.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/62131/62131fig1v3.jpg" /> 
Figure 1&#160;- Diagrammatic representation of process for using the bipartite GAL4-UAS System in Anopheles gambiae.&#160;(A) The major components of an example vector (pSL-attB-UAS14-gyp[3xp3-eYFP]) are depicted, detailing the available restriction sites (EcoRI, NheI, XhoI and NcoI) within the multiple cloning sites that are suitable for use to insert the hairpin construct or coding sequence for the gene of interest. The structure of the docking line is also depicted. (B) The crossing step is illustrated indicating the use of males from the driver line (carrying GAL4 driver by a promoter of interest and eCFP driven by the 3xP3 promoter) and females from the responder line (carrying the gene of interest or hairpin construct controlled by a UAS promoter and an eYFP marker controlled by the 3xP3 promoter). (C) A diagrammatic representation of GAL4 driving expression of the gene of interest in the progeny of the cross in B and a list of some of the typical phenotypes that are assessed. Abbreviations: Multiple Cloning Site (MCS), Recombinase mediated cassette exchange (RMCE), Upstream Activator Sequence (UAS), enhanced yellow fluorescent protein (eYFP), enhanced cyan fluorescent protein (eCFP). <a href="https://www.jove.com/files/ftp_upload/62131/62131fig1v2large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
It is the use of crosses that provides the bipartite nature of the GAL4-UAS system, which has distinct advantages over more linear approaches. For example, many more combinations of driver and responder lines can be assessed than would be feasible if a new transgenic line had to be generated and maintained for each promoter/gene combination. More importantly, it allows the analysis of genes that produce lethal or sterile phenotypes when their expression is perturbed which are difficult to create/maintain in a linear system. Such lethal phenotypes can manifest at all developmental stages, depending on the gene function and spatiotemporal expression, but are most often observed during embryonic development. Visualizing mosquito embryo development requires the clearing of the opaque chorion which coats the eggs. Following methods described in Trpi&#353; (1970)21 and Kaiser et al. (2014)22, we describe the protocols we use to fix embryos, whilst maintaining structural integrity, and bleaching to clear the endochorion that allows microscopic visualization and imaging.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>100 x 15 mm plastic Petri dish</td>
			<td>SLS</td>
			<td>2175546</td>
			<td>Pack of 10</td>
		</tr>
		<tr>
			<td>1000 &#181;L Gilson Pipette</td>
			<td>Gilson</td>
			<td>F144059P</td>
			<td></td>
		</tr>
		<tr>
			<td>20/25 mL Universal Tubes</td>
			<td>Starlab</td>
			<td>E1412-3020</td>
			<td>Pack of 400</td>
		</tr>
		<tr>
			<td>3 mL Pasteur Pipettes</td>
			<td>SLS</td>
			<td>G612398</td>
			<td>Greiner Pasteur pipette 3 mL sterile individually wrapped</td>
		</tr>
		<tr>
			<td>50 mL Falcon Tubes</td>
			<td>Fisher Scientific</td>
			<td>11512303</td>
			<td></td>
		</tr>
		<tr>
			<td>Absolute Ethanol</td>
			<td>Fisher Scientific</td>
			<td>BP2818-500</td>
			<td>500 mL</td>
		</tr>
		<tr>
			<td>Acetic Acid</td>
			<td>SLS</td>
			<td>45726-1L-F</td>
			<td>1 L</td>
		</tr>
		<tr>
			<td>Cages</td>
			<td>SLS</td>
			<td>E6099</td>
			<td>30x30x30 with screen port</td>
		</tr>
		<tr>
			<td>Fine Paint Brushes</td>
			<td>Amazon</td>
			<td>UKDPB66</td>
			<td>KOLAMOON 9 Pieces Detail Painting Brush Set Miniture Brushes for Watercolor, Acrylic Painting, Oil Painting (Wine Red)</td>
		</tr>
		<tr>
			<td>Fish food</td>
			<td>Amazon</td>
			<td></td>
			<td>Tetra Min Fish Food, Complete Food for All Tropical Fish for Health, Colour and Vitality, 10 L&#160;</td>
		</tr>
		<tr>
			<td>Formaldehyde Solution</td>
			<td>Sigma Aldrich</td>
			<td>F8775</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouth Aspirator</td>
			<td>John Hock</td>
			<td>612</td>
			<td></td>
		</tr>
		<tr>
			<td>Pond Salt</td>
			<td>Amazon</td>
			<td></td>
			<td>Blagdon Guardian Pond Tonic Salt, for Fish Health, Water Quality, General Tonic, pH Buffer, 9.08 kg, treats 9,092 L&#160;</td>
		</tr>
		<tr>
			<td>Pupae Pots</td>
			<td>Cater4you</td>
			<td>SP8OZ</td>
			<td>250 pots with lids</td>
		</tr>
		<tr>
			<td>Small Plastic Buckets</td>
			<td>Amazon</td>
			<td></td>
			<td>2.5 L White Plastic Pail Complete with White Lid (Pack of 10)&#160;</td>
		</tr>
		<tr>
			<td>Sodium Hypochlorite</td>
			<td>Fisher Scientific</td>
			<td>S25552</td>
			<td></td>
		</tr>
	</tbody>
</table>

using the gal4-uas system for functional genetics in anopheles gambiae

The bipartite GAL4-UAS system is a versatile and powerful tool for functional genetic analysis. The essence of the system is to cross transgenic 'driver' lines that express the yeast transcription factor GAL4 in a tissue specific manner, with transgenic 'responder' lines carrying a candidate gene/RNA interference construct whose expression is controlled by Upstream Activation Sequences (UAS) that bind GAL4. In the ensuing progeny, the gene or silencing construct is thus expressed in a prescribed spatiotemporal manner, enabling the resultant phenotypes to be assayed and gene function inferred. The binary system enables flexibility in experimental approaches to screen phenotypes generated by transgene expression in multiple tissue-specific patterns, even if severe fitness costs are induced. We have adapted this system for Anopheles gambiae, the principal malaria vector in Africa.
In this article, we provide some of the common procedures used during GAL4-UAS analysis. We describe the An. gambiae GAL4-UAS lines already generated, as well as the cloning of new responder constructs for upregulation and RNAi knockdown. We specify a step by step guide for sexing of mosquito pupae to establish genetic crosses, that also includes screening progeny to follow inheritance of fluorescent gene markers that tag the driver and responder insertions. We also present a protocol for clearing An. gambiae embryos to study embryonic development. Finally, we introduce potential adaptions of the method to generate driver lines through CRISPR/Cas9 insertion of GAL4 downstream of target genes.

3xP3 expression of eYFP, dsRed and eCFP provides reliable, readily distinguishable identification of individuals possessing the marker genes producing expression in eyes and ventral ganglia of&#160;An. gambiae&#160;pupae (Figure 3). The differential morphology observed in male and female external genitalia used for sexing and an example of an unidentifiable pupae are highlighted in&#160;Figure 4. Removal of all water from pupae increases sexing...

Watch this Scientific Journal Video about Using the GAL4-UAS System for Functional Genetics in Anopheles gambiae at JoVE.com

Using the GAL4-UAS System for Functional Genetics in Anopheles gambiae

The bipartite GAL4-UAS system is a versatile tool for modification of gene expression in a controlled spatiotemporal manner which permits functional genetic analysis in Anopheles gambiae. The procedures described for using this system are a semi-standardized cloning strategy, sexing and screening of pupae for fluorescent protein markers and embryo fixation.

Using the GAL4-UAS System for Functional Genetics in Anopheles gambiae

The bipartite GAL4-UAS system is a versatile and powerful tool for functional genetic analysis. The essence of the system is to cross transgenic 'driver' ...

Research

JoVE Journal

Genetics

Analysis of the Ambient Particulate Matter-induced Chromosomal Aberrations Using an In Vitro System

Analysis of the Ambient Particulate Matter-induced Chromosomal Aberrations Using an In Vitro System

Exposure to particulate matter (PM) is a major world health concern, which may damage various cellular components, including the nuclear genetic material. ...

Detection of Copy Number Alterations Using Single Cell Sequencing

Detection of genomic changes at single cell resolution is important for characterizing genetic heterogeneity and evolution in normal tissues, cancers, and ...

Systemic Delivery of MicroRNA Using Recombinant Adeno-associated Virus Serotype 9 to Treat Neuromuscular Diseases in Rodents

RNA interference via the endogenous miRNA pathway regulates gene expression by controlling protein synthesis through post-transcriptional gene silencing. ...

Determination of the Optimal Chromosomal Location(s) for a DNA Element in Escherichia coli Using a Novel Transposon-mediated Approach

Determination of the Optimal Chromosomal Locations for a DNA Element in Escherichia coli Using a Novel Transposon-mediated Approach

The optimal chromosomal position(s) of a given DNA element was/were determined by transposon-mediated random insertion followed by fitness selection. In ...

High Resolution Fluorescent In Situ Hybridization in Drosophila Embryos and Tissues Using Tyramide Signal Amplification

High Resolution Fluorescent In Situ Hybridization in Drosophila Embryos and Tissues Using Tyramide Signal Amplification

In our efforts to determine the patterns of expression and subcellular localization of Drosophila RNAs on a genome-wide basis, and in a variety of ...

CRISPR-Mediated Reorganization of Chromatin Loop Structure

Recent studies have clearly shown that long-range, three-dimensional chromatin looping interactions play a significant role in the regulation of gene ...

Measuring Exercise Levels in Drosophila melanogaster Using the Rotating Exercise Quantification System (REQS)

Measuring Exercise Levels in Drosophila melanogaster Using the Rotating Exercise Quantification System REQS

Drosophila melanogaster is a new model organism for studies in exercise biology. To date, two main exercise systems, the Power Tower and the Treadwheel ...

Identification of Homologous Recombination Events in Mouse Embryonic Stem Cells Using Southern Blotting and Polymerase Chain Reaction

Relative to the issues of off-target effects and the difficulty of inserting a long DNA fragment in the application of designer nucleases for genome ...

In vivo Application of the REMOTE-control System for the Manipulation of Endogenous Gene Expression

Here we describe a protocol for implementing the REMOTE-control system (Reversible Manipulation of Transcription at Endogenous loci), which allows for ...

In Vivo Functional Study of Disease-associated Rare Human Variants Using Drosophila

In Vivo Functional Study of Disease-associated Rare Human Variants Using Drosophila

Advances in sequencing technology have made whole-genome and whole-exome datasets more accessible for both clinical diagnosis and cutting-edge human ...