The ongoing R. prolixus Genome Project could provide important tools for the study of genetic programming

of oocyte development and atresia and also for mechanisms related to PCD. The authors thank Jose de Lima Junior and Litiane M. Rodrigues for maintaining the insect colony. This work was supported by the following agencies: Fundação Carlos Chagas Filho de Apoio à Pesquisa do Estado do Rio de Janeiro (FAPERJ), Programa de Apoio a Núcleos de Excelência do Ministério da Ciência e Tecnologia (PRONEX-MCT) and Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (CNPq). “
“Vitellogenin is the precursor of vitellin, a phospholipoglycoprotein that constitutes the major fraction of the egg yolk proteins in insects and is the main source of nutrients for the embryo (Raikhel and Dhadialla, 1992 and Tufail and Takeda, 2008). Enzalutamide In insects, the amino acid sequence of vitellogenins is conserved at many sites (Chen et al., 1997 and Tufail and Takeda, 2008), although the number of genes that encode

them varies in different species. In hemimetabolous insects, one gene is present in Blattella germanica (Blattaria) ( Comas et al., 2000) and two genes in Leucophaea maderae (Blattaria) ( Tufail et al., 2007). For holometabola insects, five genes were identified in Aedes aegypti (Diptera) find more ( Chen et al., 1994), one in both Bombyx mori (Lepidoptera) ( Yano et al., 1994) and Apis mellifera (Hymenoptera) ( Piulachs et al., 2003), and three in Solenopsis invicta (Hymenoptera) ( Tufail and Takeda, 2008). Vitellogenin is mainly

synthesized in the fat body of females, where single or multiple polypeptides undergo modifications such as glycosylation, lipidification, phosphorylation, sulfation, and proteolytic cleavage (Tufail and Takeda, 2008). They are then released into the haemolymph as oligomeric proteins with molecular weights ranging Rutecarpine from 300 to 600 kDa (Tufail and Takeda, 2008 and Wheeler et al., 1999). These protein aggregates are then transferred to oocytes via receptor-mediated endocytosis and stored in the form of crystals, at which time they are termed vitellins (Giorgi et al., 1999 and Raikhel and Dhadialla, 1992). In social insects, the production of vitellogenins is not exclusive to queens, the reproductive females, but also occurs in the non- or subfertile worker castes (Engels, 1974, Guidugli et al., 2005 and Seehuus et al., 2006), and in the honey bee it was even found in males (Piulachs et al., 2003 and Trenscek et al., 1989). Workers of the stingless bee Frieseomelitta varia are sterile but produce vitellogenin constitutively throughout their life ( Dallacqua et al., 2007).