UCR

Department of Entomology



Faculty


Alexander Raikhelucrentomology

Distinguished Professor of Entomology

Location: Entomology 338
Tel: (951) 827-2129
E-mail: alexander.raikhel@ucr.edu

Biography

Mosquitoes transmit numerous diseases, and some of them are among the most threatening in modern times. Malaria is particularly devastating, taking a heavy toll on the human population in many parts of the world by infecting over 300 million and killing over 2 million people each year. The situation in Sub-Saharan Africa, where 90 percent of all malaria cases occur, has become a human catastrophe. Diseases caused by mosquito-borne viruses, most importantly Dengue fever, are reaching disastrous levels in South and Central America. In the U.S., the West Nile encephalitis virus is rapidly spreading westward, after appearing first on the East Coast. Lymphatic filariasis, a nematode-based disease transmitted by mosquitoes, affects millions of people in world’s tropical regions. The major reasons for this tragic situation are the unavailability of effective vaccines for malaria and other mosquito-borne diseases and the development of insecticide and drug resistance by the vectors and pathogens, respectively. Therefore, there is an urgent need to explore every possible avenue for developing novel control strategies against these menacing mosquito-borne diseases. My research is focusing on understanding the molecular basis of events in the mosquito reproduction cycle linked to a blood meal and pathogen transmission. Mosquitoes serve as vectors of many devastating human diseases because they need blood feeding in order to develop eggs. This requirement of a blood meal, called anautogeny, results in a highly regulated cyclicity of egg production as each cycle is tightly coupled with blood intake. Anautogeny is one of most fundamental phenomena underlying the vectorial capacity of mosquitoes. Thus, understanding the molecular and genetic basis of anautogeny is of great importance for the future development of novel approaches to vector and pathogen control. Recent Reviews Raikhel, A.S., Kokoza, V.A., Zhu, J., Martin, D., Wang, S-F., Li, C., Sun, G., Ahmed, A., Dittmer., N., and Attardo, G. (2002). Molecular biology of mosquito vitellogenesis: From basic studies to genetic engineering of anti-pathogen immunity. Insect Biochem. Molec. Biol. 32, 1275-1286. Raikhel, A.S. (2003). Vitellogenesis of disease vectors, from cell biology to genes. In The Biology of Vectors, B. Beaty and W. Marquardt, eds. San Diego: Academic Press, (in Press). Yolk Proteins and their Receptors My research has focused on the biochemical and molecular understanding of the egg maturation mechanism in mosquitoes. Cell biological studies of the synthesis of yolk protein precursors by the insect’s metabolic tissue and their accumulation by developing oocytes were followed by biochemical investigation of vitellogenin (Vg) biosynthesis, the major yolk protein precursor. The precursor-product relationship and the major steps in biosynthesis of mosquito Vg, as well as the analysis of its protein sequence, have been pursued. A protease responsible for specific cleavage of the pro-Vg molecule was identified. This was the first demonstration that subtilisin-like pro-protein convertases, which are serine proteases implicated in proteolytic processing of neurohormone precursors, are involved in the processing of a major secretory protein. A new biological phenomenon discovered by my research group is that the fat body, an insect metabolic tissue that is analogous to the vertebrate liver, produces several pro-enzymes in addition to Vg. These pro-enzymes are secreted into the circulatory system, accumulated by developing oocytes, and stored in yolk spheres. At the onset of embryonic development, these proteases are activated to degrade vitellogenin, providing the embryo with nutrients. In my laboratory, the first insect Vg receptor (VgR), which represents a novel group of membrane receptors belonging to the family of low-density lipoprotein (LDL) receptors, has been isolated and characterized. We are interested in understanding the binding properties of VgR and other yolk protein receptors in the mosquito oocytes. Protein modeling is being used together with binding studies to elucidate unique features of these LDL-related receptors. Transgenic studies are being employed to investigate the regulation of VgR gene expression in germ-line cells of the mosquito ovary. Molecular Endocrinology The egg maturation in mosquitoes is cyclical, and a blood meal is required for the activation of each cycle. The insect steroid hormone ecdysone plays a central stage in regulation of these developmental events. In my laboratory, we study the molecular basis for hormonal regulation of egg maturation in mosquitoes. In particular, we are interested how nuclear receptors mediate the action of ecdysone in gene activation and repression during vitellogenesis. The functional ecdysteroid receptor is a heterodimer of two nuclear receptors—the ecdysone receptor (EcR) and the retinoid X receptor homolog Ultraspiracle (USP). The mosquito EcR-USP heterodimer is capable of binding to various EcREs to modulate ecdysone regulation of target genes. The binding of the EcR/USP heterodimer to the regulatory region of the Vg gene is required for its activation. The early genes E74 and E75 are induced in response to blood feeding in vitellogenic tissues, the fat body, and the ovary, and their products are involved in mediating the ecdysteroid response during vitellogenesis. The early genes E74 and E75 are necessary for a high level of Vg gene expression. Our research has shown that the cyclicity of vitellogenic ecdysteroid-mediated signaling in the mosquito fat body is regulated through USP, which sequentially forms active or inactive heterodimers with either repressors or the activator (EcR), respectively. Activation of transcription of hormonally controlled, tissue-specific genes involves synergistic interactions of sequence-specific transcription factors with enhancer/promoter elements of these genes. In my laboratory, we are interested in understanding exactly what combination of transcription factors of hormonal, stage-specific, and tissue-specific regulatory pathways brings specific expression of mosquito fat body genes. The elucidation of the molecular mechanisms underlying stage- and tissue-specific expressions of genes activated by a blood meal is of great importance for current efforts to utilize molecular genetics to develop new strategies for mosquito and pathogen control. The regulatory regions of such genes can be used to express anti-pathogen effector molecules in engineered vectors in a precise temporal and spatial manner that is designed to maximally affect a pathogen. The fat body is a particularly important target for engineering anti-pathogen properties, because in insects it is a potent secretory tissue that releases its products to the hemolymph, which is an environment or a crossroad for most pathogens. In my laboratory, we have employed various molecular and genetic tools to study cis-regulatory sites of the Vg gene responsible for stage- and fat body-specific activation of this gene via a blood-meal-triggered cascade. This research serves as a foundation for the future design of mosquito-specific expression cassettes with predicted stage and tissue specificity at the desired levels of transgene expression. The processes of activation of innate immune factors in mammals and insects share a conserved pathway in which Rel/NF-êB transcription factors are the chief regulators. Natural immune factors can be used as potential anti-pathogen effector molecules in engineered vectors. However, little is known about the pathways regulating the immune responses in mosquitoes, despite the enormous importance of such knowledge for our understanding of the immune system of these disease vectors. The Rel/NF-êB transcription factor Relish performs a central role in the acute-phase response to microbial challenge by activating immune anti-bacterial peptides. In my laboratory, we cloned and characterized the Aedes Relish gene. This gene gives rise to alternatively spliced transcripts encoding different proteins similar to the mammalian p105 and p100 Rel/NF-êB transcription factors. We have generated Relish-mediated immune deficiency in transgenic Aedes by using the cDNA to encode the Rel-type transcript that contained only the Rel homology domains without the IêB-like domain. The DRel transgene driven by the Vg promoter was highly activated by blood feeding. The blood-fed transgenic mosquitoes were extremely susceptible to infection by Gram (-) bacteria. We have engineered stable transformant lines of Aedes aegypti, in which the regulatory region of the Vg gene activates high-level fat body-specific expression of the potent anti-bacterial peptides, defensin and cecropin, in response to a blood meal. These studies have opened the door for future studies of the molecular and genetic basis of immunity in mosquitoes using reverse genetics.  

Former Institution

Department of Entomology, Michigan State University

Degrees

MS Zoology-Parasitology 1970
St. Petersburg University, Russia
PhD Zoology-Parasitology 1975
Zoological Institute, Academy of Science, St. Petersburg, Russia

Awards

2009 University of California Presidential Chair
2009 Fellow of Entomological Society of America
2009 Member of the National Academy of Sciences
2004 MERIT Award from the National Institutes of Health
2002 Fellow of the American Association for the Advancement of Science
2001 Entomological Society of America Recognition Award in Insect Physiology, Biochemistry, and Toxicology
2000 Michigan State University Distinguished Faculty Award
1999- 2006 Editor, Insect of Biochemistry and Molecular Biology, Elsevier Science

Publications

Shin, S.W., Zou, Z., and Raikhel, A.S. 2011. A new player in the Aedes aegypti immune response: CLSP2 modulates melanization. EMBO Reports, E-pub ahead of press

Kokoza, V.A. and Raikhel, A.S. 2011. Targeted gene expression in the transgenic Aedes aegypti using the binary Gal4-UAS system. Insect  Biochem. Mol. Biol. 41: 637-644

 

Hansen, I. A., Boudko, D.Y, et al. 2011. AaCAT1 of the Yellow Fever Mosquito, Aedes aegypti, a novel Histidine-specific Amino Acid Transceptor from the SLC7 Family. J. Biol. Chem. 286: 10803-10813.

Neira-Oviedo, M., Tsyganov-Bodounov, A, et al. 2011. The RNA-Seq approach to studying the expression of mosquito mitochondrial genes. Insect Mol. Biol. 20: 141-152.  

Roy, S. G. and Raikhel, A. S. 2011. The small GTPase Rheb is a key component linking amino acid signaling and TOR in the nutritional pathway controlling mosquito egg development. Insect Biochem. Mol. Biol. 41:62-69.

Arensburger,P., Megy. K., et al. 2010 Sequencing of Culex quinquefasciatus Establishes a Platform for Mosquito Comparative Genomics Science 330: 86 – 88

Bartholomay,L.C.,Waterhouse, R. M., et al. 2010. Pathogenomics of Culex quinquefasciatus and Meta-Analysis of Infection Responses to Diverse Pathogens. Science 330: 88-90.

Bryant, B., Mcdonald, W., and Raikhel, A.S. 2010. miR-275 is indispensable for blood digestion and egg development in the mosquito Aedes aegypti. Proc. Natl. Acad. Sci. USA(inaugural article)

Kokoza, V., Ahmed, A., et al. Shin, S. W., Okafor, N., Zou, Z., and Raikhel, A.S. 2010. Blocking of Plasmodium transmission by cooperative action of Cecropin A and Defensin A in transgenic Aedes aegypti mosquitoes. Proc. Natl. Acad. Sci. USA 107: 8111-8116.


Zou, Z., Shin, S.W., Alvarez, K.S., Kokoza, K., and Raikhel, A.S. 2010. Distinct melanization mechanisms in the mosquito Aedes aegypti. Immunity 32:41-53.
Antonova, Y., Alvarez, K. S., Kim, Y.J., Kokoza, V. and Raikhel, A.S. 2009. The role of NF-κB factor REL2 in the Aedes aegypti immune response. Insect Biochem. Mol. Biol. 39: 303-314.

Cruz, J., Sieglaff, D.H., Arensburger, P., Atkinson, P.W. and Raikhel, A.S. 2009. Nuclear receptors in the mosquito Aedes aegypti: annotation, hormonal regulation and expression profiling. FEBS J. 276:1233-1254.

Zou, Z., Shin, S.W., Alvarez, K.S., Bian, G., Kokoza, K., and Raikhel, A.S. 2008 Mosquito RUNX4 in the immune regulation of PPO gene expression and its effect on avian malaria parasite infection. Proc. Natl. Acad. Sci. USA 105: 18454-18459.

Shiao S.H., Hansen I. A., Zhu J., Sieglaff D.H., Raikhel A. S. 2008. Juvenile hormone connects larval nutrition with target of rapamycin signaling in the mosquito Aedes aegypti. J. Insect Physiol. 54: 231-239.

Bian G., Raikhel A. S., Zhu J. 2008. Characterization of a juvenile hormone-regulated chymotrypsin-like serine protease gene in Aedes aegypti mosquito.
Insect Biochem Mol Biol. 38:190-200.

Mishra, S.K., Jha, A., Steinhauser, A.L., Kokoza, V.A., Washabaugh, C.H., Raikhel, A.S., Foster, W.A. and Traub, L.M. 2008. Internalization of LDL-receptor superfamily yolk-protein receptors during mosquito oogenesis involves transcriptional regulation of PTB-domain adaptors. J. Cell Sci. 121: 1264-1274.

Zhu, J., Chen, L., and Raikhel, A.S. 2007. Distinct roles of Broad isoforms in regulation of 20-hydroxyecdysone effector gene, vitellogenin, in the mosquito Aedes aegypti. Mol. Cell. Endocrinol. 97-105.

Hansen, I.A., Sieglaff, D.H., Munro, J.B., Shiao, S.H., Cruz, J., Lee, I.W., Heraty, J.M. and Raikhel, A.S. Forkhead transcription factors regulate mosquito reproduction. 2007. Insect Biochem. Mol. Biol. 37: 985-997.

Dhadialla, T.S., Le, D., Palli, S.R., Raikhel, A. and Carlson, G.R. A photoaffinity, non-steroidal, ecdysone agonist, bisacylhydrazine compound, RH-131039: characterization of binding and functional activity. 2007. Insect Biochem. Mol. Biol. 37: 865-875.

Nene, V., Wortman, J. R., Lawson, D., Haas, B., Kodira, C., Tu, Z. J., Loftus, B., Xi, Z., Megy, K., Grabherr, M., Ren, Q., Zdobnov, E. M., Lobo, N. F. Campbell, K. S., Brown, S. E., Bonaldo, M. F., Zhu, J., Sinkins, S. P., Hogenkamp, D. G., Amedo, P., Arsenburger, P., Atkinson, P. W., Bidwell, S., Biedler, J., Birney, E., Bruggner, R.V., Costas, J., Coy, M. R., Crabtree, J., Crawford, M., deBruyn, B., DeCaprio, D., Eiglmeier, K., Eisenstadt, E., El-Dorry, H., Gelbart, W. M., Gomes, S. L., Hammond, M., L.I. Hannick, J.R. Hogan, M.H. Holmes, D.Jaffe, S. J. Johnston, R.C. Kennedy, H. Koo, S. Kravitz, E.V. Kriventseva, D. Kulp, K. LaButti, E. Lee, S. Li, D. D. Lovin, C. Mao, E. Mauceli, C. F. M. Menck, J. R. Miller, P. Montgomery, A. Mori, A. L. Nascimento, H. F. Naveira, C. Nusbaum, S. B. O’Leary, J. Orvis, M. Pertea, H. Quesneville, K. R. Reidenbach, Y.H. Rogers, C.W. Roth, J. R. Schneider, M. Schatz, M. Shumway, M. Stanke, E. O. Stinson, J. M. C. Tubio, J. P. VanZee, S. Verjovski-Almeida, D.Werner, O.White, S.Wyder, Q. Zeng, Q. Zhao, Y. Zhao, C.A. Hill, Raikhel, A. S., M. B. Soares, D. L. Knudson, N.H. Lee, J.Galagan, S.L. Salzberg, I.T. Paulsen, Dimopoulos, G., F.H. Collins, B.Bruce, Fraser-Liggett, C. M., Severson. D. W. 2007. Genome Sequence of Aedes aegypti, a Major Arbovirus Vector. Science, 316: 1718-1723.

Waterhouse RM, Kriventseva EV, Meister S, Xi Z, Alvarez KS, Bartholomay LC, Barillas-Mury C, Bian G, Blandin S, Christensen BM, Dong Y, Jiang H, Kanost MR, Koutsos AC, Levashina EA, Li J, Ligoxygakis P, Maccallum RM, Mayhew GF, Mendes A, Michel K, Osta MA, Paskewitz S, Shin SW, Vlachou D, Wang L, Wei W, Zheng L, Zou Z, Severson DW, Raikhel AS, Kafatos FC, Dimopoulos G, Zdobnov EM, Christophides GK. 2007. Evolutionary dynamics of immune-related genes and pathways in disease-vector mosquitoes. Science, 316: 1738-1743.

Roy S.G., Hansen I. A., Raikhel A. S. 2007. Effect of insulin and 20-hydroxyecdysone in the fat body of the yellow fever mosquito, Aedes aegypti. Insect Biochem Mol Biol. 37:1317-1326.

Attardo, G. M., Hansen, I. A., Shiao, S.H. and Raikhel, A. S. 2006. Identification of two cationic amino acid transporters required for nutritional signaling during mosquito reproduction. J. Exp. Biol, 209, 3071-3078.

Cheon, H.-M., Shin, S.W., Bian, G., Park, J.H. and Raikhel, A.S. 2006. Regulation of lipid metabolism genes, lipid carrier protein lipophorin and its receptor, during immune challenge in the mosquito Aedes aegypti. J. Biol. Chem. 281, 8426-8435.

Cho, K.H., Cheon, H.-M., Kokoza, V. and Raikhel, A. S. 2006. Regulatory region of the vitellogenin receptor gene sufficient for high level, germ line cell-specific expression in the ovary of transgenic Aedes aegypti mosquitoes. Insect Biochem. Mol. Biol. 36, 273-281.

Park, J. H., Attardo, G. M., Hansen, I. A. and Raikhel, A. S. 2006. GATA factor translation is the downstream step in the TOR-mediated amino acid activation of vitellogenin gene expression in the anautogenous mosquito, Aedes aegypti. J. Biol. Chem. 281, 11167-11176.

Shin, S. W., Bian, G. and Raikhel, A. S. 2006. A Toll receptor and a cytokine, AaToll5 and Spz1C, are involved in Toll anti-fungal immune signaling in the mosquito Aedes aegypti. J. Biol. Chem. 281, 39388-39395.

Zhu, J. Chen, L., Sun, G. and Raikhel, A. S. 2006. The competence factor bFtz-F1 potentiates ecdysone receptor activity via recruitment of a p160/SRC coactivator. Mol. Cell. Biol. 26: 9402-9412.

Attardo, G.M., Hansen I.A. and Raikhel, A.S. 2005. Nutritional regulation of vitellogenesis in mosquitoes: Implications for anautogeny. Insect Biochem. Mol. Biol. 35, 661-675.

Bian, G., Shin, S.W., Cheon, H. M., Kokoza, V. and Raikhel, A. S. 2005. Transgenic alteration of Toll immune pathway in the female mosquito Aedes aegypti. Proc. Natl. Acad. USA 102, 13568-13573.

Hansen, I. A., Attardo, G. M., Roy, S. G. and Raikhel, A. S. 2005. Target of rapamycin – dependent activation of S6 kinase is a central step in the transduction of nutritional signal during egg development in a mosquito. J. Biol. Chem. 280: 20565-20572.

Giorgi F., Snigirevskaya, E.S. and Raikhel, A. S. 2005. The Cell Biology of yolk protein synthesis and secretion. In: Progress in Vitellogenesis, (A. S. Raikhel, ed.); series Reproductive Biology of Invertebrates (K.G. Adiyodi and R. G. Adiyodi, eds.). Vol. XII, Part B, pp. 33-68. Science Publishers, Inc., Enfield, USA- Plymouth, UK.

Martin, D., Attardo, G. M., Hansen, I. A., and Raikhel, A.S. 2005. Control of tissue-specific gene expression. In: Progress in Vitellogenesis, (A. S. Raikhel, ed.); series Reproductive Biology of Invertebrates (K.G. Adiyodi and R. G. Adiyodi, eds.). Vol. XII. Part B. pp. 129-156. Science Publishers, Inc., Enfield, USA- Plymouth, UK.

Sappington, T. W. and Raikhel, A. S. 2005. Insect Vitellogenin/Yolk Protein Receptors. In: Progress in Vitellogenesis, (A. S. Raikhel, ed.); series Reproductive Biology of Invertebrates (K.G. Adiyodi and R. G. Adiyodi, eds.). Vol. XII, Part B, pp. 229-264. Science Publishers, Inc., Enfield, USA- Plymouth, UK.

Severs, L., Raikhel, A.S., Sappington, T., Shirk, P., and Iatrou, K. 2005. Oocyte development In: Comprehensive Molecular Insect Science (L Gilbert, S Gill and K. Iatrou eds.) Vol. 1. Reproduction and Development, pp. 87-156. Elsevier Press.

Shin, S. W., Kokoza, V., Bian, G., Cheon, H. M., Kim, Y. J. and Raikhel, A. S. 2005. REL1, a homologue of Dorsal regulates toll antifungal immune pathway in the female mosquito, Aedes aegypti. J. Biol. Chem. 280: 16499-16507.

Snigirevskaya, E.S. and Raikhel, A. S. 2005. Receptor-mediated endocytosis of yolk proteins in insect oocytes. In: Progress in Vitellogenesis, (A. S. Raikhel, ed.); series Reproductive Biology of Invertebrates (K.G. Adiyodi and R. G. Adiyodi, eds.). Vol. XII, Part B, pp. 199-228. Science Publishers, Inc., Enfield, USA- Plymouth, UK.

Sun, G., Zhu, J., Chen, L. and Raikhel, A. S. 2005. Synergistic action of E74B and Ecdysteroid Receptor in activating a 20-hydroxyecdysone effector gene. Proc. Natl. Acad. USA 102, 15506-15511.

Raikhel, A.S., M. Brown and Belles, X. 2005. Endocrine Control of Reproductive Processes. In: Comprehensive Molecular Insect Science (L Gilbert, S Gill and K. Iatrou eds.) Vol. 3, Endocrinology, pp. 433-491. Elsevier Press.

Tufail, M., Raikhel, A. S. and Takeda, M. 2005. Biosynthesis and processing of insect vitellogenins. In: Progress in Vitellogenesis, (A. S. Raikhel, ed.); series Reproductive Biology of Invertebrates (K.G. Adiyodi and R. G. Adiyodi, eds.). Vol. XII, Part B, pp. 1-32, Science Publishers, Inc. Enfield, USA- Plymouth, UK.

Wang, S.-F., Zhu, J., Martin, D. and Raikhel, A. S. 2005. Regulation of yolk protein genes by ecdysone. In: Progress in Vitellogenesis, (A. S. Raikhel, ed.); series Reproductive Biology of Invertebrates (K.G. Adiyodi and R. G. Adiyodi, eds.). Vol. XII, Part B, pp. 69-94. Science Publishers, Inc. Enfield, USA- Plymouth, UK.

Sun, G., Zhu, J. Chen, L. and Raikhel, A.S. 2004. The early gene E74B isoform is a transcriptional activator of the ecdysteroid regulatory hierarchy in mosquito vitellogenesis. Mol. Cell. Endocrinol. 218: 95-105.

Hansen, I. A., Attardo, G. M., Park, J.-H., Peng, Q., and Raikhel, A.S. 2004. TOR-mediated amino acid signaling in mosquito anautogeny. Proc. Natl. Acad. USA 101: 10626-10631.

Chen, L., Zhu, J., Sun, G and Raikhel, A.S. 2004. The early gene Broad is involved in the ecdysteroid hierarchy governing vitellogenesis of the mosquito Aedes aegypti. J. Mol. Endocrinol. 33: 743-761.

Raikhel, A.S. 2004. Vitellogenesis of Disease Vectors, from Cell Biology to Genes. In: The Biology of Vectors. (B. Beaty and W. Marquardt, eds). Elsevier-Academic Press, pp. 329-346.

Zhu, J., Kokoza, V. and Raikhel, A.S. 2004. Control of Gene Expression. In: The Biology of Vectors. (B. Beaty and W. Marquardt, eds). Elsevier- Academic Press, 565-586.

Attardo, G., S. Higgs, K. A. Klingler, D. L. Vanlandingham, and Raikhel, A. S.. 2003. RNAi-mediated knockdown of a GATA factor reveals a link to anautogeny in the mosquito, Aedes aegypti. Proc. Natl. Acad. 100: 13374-13379.

Zhu, J., Chen, L. and Raikhel, A. S. 2003. Post-transcriptional control of the competence factor betaFtz-F1 by juvenile hormone in the mosquito Aedes aegypti. Proc. Natl. Acad. USA. 100, 13334-13343.

Shin, S. W., Kokoza, V. and Raikhel, A. S. 2003. Reverse genetics of mosquito innate immunity. J. Exp. Biol. 206: 3835-3843.

Raikhel, A. S., McGurk, L. and Bownes, M. 2003. Ecdysteroid action insect reproduction. In: Encyclopedia of Hormones. (H. L. Henry and A. W. Norman, eds/). Academic Press. Vol. 1: pp. 451-459

Seo, S. J., Cheon, H. M., Sun, J., Sappington, T. and Raikhel, A. S. 2003. Tissue- and stage-specific expression of two lipophorin receptor variants with 7 and 8 ligand-binding repeats in the adult female mosquito, Aedes aegypti. J. Biol. Chem, 278: 41954-41962.

Shin, S. W., Kokoza, V., Lobkov, Y. and Raikhel, A. S. 2003. Relish-mediated immunodeficiency in the transgenic mosquito, Aedes aegypti. Proc. Natl. Acad. USA 100: 2616-2632.

Zhu, J. S., K. Miura, L. Chen, and A. S. Raikhel. 2003. Cyclicity of mosquito vitellogenic ecdysteroid-mediated signaling is modulated by alternative dimerization of the RXR homolog, Ultraspiracle. Proc. Natl. Acad. USA, 100: 544-549.

Dittmer, N.T., Sun, G., Wang, S.F. and Raikhel, A.S. 2003. CREB isoform represses yolk protein gene expression in the mosquito fat body. Mol. Cell. Endocrinol. 210: 39-49.

Raikhel, A.S., Kokoza, V.A., Zhu, J., Martin, D., Wang, S-F., Li, C., Sun, G., Ahmed, A., Dittmer., N., and Attardo, G. 2002. Molecular biology of mosquito vitellogenesis: From basic studies to genetic engineering of anti-pathogen immunity. Insect Biochem. Molec. Biol. 32,1275-1286.

Shin, S.W., Kokoza, V., Ahmed, A., and Raikhel, A.S. 2002. Characterization of three alternatively spliced isoforms of the Rel/NF-êB transcription factor Relish from the mosquito Aedes aegypti. Proc. Natl. Acad. USA, 99: 9978-9983.

Sun, G., Zhu, J.S., Li, C., L., Tu, J. and Raikhel, A.S. 2002. Two isoforms of the early E74 gene, an Ets transcription factor homologue, are utilized in the ecdysteroid hierarchy governing vitellogenesis of the mosquito, Aedes aegypti. Molec. Cell. Endocrinol. 190: 147-157.

Martin, D., Piulachs, M.D., Raikhel, A.S. 2001. A novel GATA factor transcriptionally represses yolk protein precursor genes in the mosquito Aedes aegypti via interaction with CtBP corepressor. Molec. Cell. Biol., 21: 164-174.

Kokoza, V.A., Martin, D., Mienaltowski, M., Ahmed, A., Morton, C., and Raikhel, A.S. 2001. Transcriptional regulation of the mosquito Aedes aegypti vitellogenin gene by a bloodmeal-triggered cascade. Gene, 274: 47-65.

Zhu, J., Miura, K., Chen, L., and Raikhel, A.S. 2000. AHR38, a homolog of NGFI-B, inhibits formation of the functional ecdysteroid receptor in the mosquito. Aedes aegypti. EMBO J, 19: 253-262.

Wang, S.F., Ayer, S., Segraves, W.A., Williams, D., and Raikhel, A.S. 2000. Molecular determinants of differential ligand sensitivity of insect ecdysteroid receptors. Molec. Cell. Biol., 20: 3870-3879.

Kokoza, V.A., Ahmed, A., Cho, W.-L., Jasinskiene, N., James, A., and Raikhel, A.S. 2000. Engineering blood meal-activated systemic immunity in the yellow fever mosquito, Aedes aegypti. Proc. Natl. Acad. USA, 97: 1624-1629.

Wang, S.F., Li, C., Zhu, J., Miura, K., Miksicek, R.J., and Raikhel, A.S. 2000. Differential expression and regulation of by 20-hydroxyecdysone of mosquito Ultraspiracle isoforms. Develop. Biol., 218: 99-113.

Ahmed, A., Martin, D., Manetti, A., Lee, W.-J., Mathiopoulos, K., Muller, H.M., Kafatos, F.C., Raikhel, A.S., and Brey, P.T. 1999. Genomic structure and ecdysone regulation of prophenoloxidase 1 gene in the malaria vector Anopheles gambiae. Proc. Natl. Acad. USA, 96: 14795-14800.

Cho, W.L., Tsao, S.M., Hays, A.R., Walter, R., Chen, J.S., Snigirevskaya, E.S., and Raikhel, A.S. 1999. Mosquito cathepsin B-like protease involved in embryonic degradation of vitellin is produced as a latent extraovarian precursor. J. Biol. Chem, 274:13311-13321.

Sappington, T.W., and Raikhel, A.S. 1998. Ligand-binding domains in vitellogenin receptors and other LDL-receptor family members share a common ancestral ordering of cysteine-rich repeats. J. Molec. Evol., 46: 476-487.

Kapitskaya, M.Z., Dittmer, N., Deitsch, K.W., Cho, W.L., and Raikhel, A.S. 1998. Three isoforms of the HNF-4 homologue highly expressed in the mosquito during egg maturation. J. Biol. Chem., 273: 29801-29810.

Sappington, T.W., Kokoza, V.A., Cho, W.L., and Raikhel, A.S. 1996. Molecular characterization of the mosquito vitellogenin receptor reveals unexpected high homology to the Drosophila yolk protein receptor. Proc. Natl. Acad. USA, 93: 8934-8939.

Chen, J.-S., and Raikhel, A.S. 1996. Subunit cleavage of insect pro-vitellogenin by a subtilisin-like convertase: characterization of the mosquito convertase. Proc. Natl. Acad. USA, 93: 6186-6190.


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