A Novel GATA Factor Transcriptionally Represses Yolk Protein Precursor Genes in the Mosquito Aedes aegypti via Interaction with the CtBP Corepressor

Abstract

In anautogenous mosquitoes, vitellogenesis, the key event in egg maturation, requires a blood meal. Consequently, mosquitoes are vectors of many devastating human diseases. An important adaptation for anautogenicity is the previtellogenic arrest (the state of arrest) preventing the activation of the yolk protein precursor (YPP) genes Vg and VCP prior to blood feeding. A novel GATA factor (AaGATAr) that recognizes GATA binding motifs (WGATAR) in the upstream region of the YPP genes serves as a transcriptional repressor at the state of arrest. Importantly, AaGATAr can override the 20-hydroxyecdysone transactivation of YPP genes, and its transcriptional repression involves the recruitment of CtBP, one of the universal corepressors. AaGATAr transcript is present only in the adult female fat body. Furthermore, in nuclear extracts of previtellogenic fat bodies with transcriptionally repressed YPP genes, there is a GATA binding protein forming a band with mobility similar to that of AaGATAr. The specific repression of YPP genes by AaGATAr in the fat body of the female mosquito during the state of arrest represents an important molecular adaptation for anautogenicity.

GATA Proteins Work Together with Friend of GATA (FOG) and C-terminal Binding Protein (CTBP) Co-regulators to Control Adipogenesis

“…Here the GATA protein, AaGATAr, directly recruits CTBP through its own PXDLS-like motif, rather than via a FOG cofactor, and functions in the repression of fat body formation (41). This link, together with the observation that the GATA factor Serpent controls fat formation in Drosophila suggests that GATA and CTBPs have a long evolutionary history of controlling fat production.…”

Nuclear receptor BgFTZ‐F1 regulates molting and the timing of ecdysteroid production during nymphal development in the hemimetabolous insect Blattella germanica

“…Preparations of nuclear extracts from B. germanica fat bodies were carried out according to the method described by Miura et al (1999) and Martín et al (2001a). Twenty fat bodies were used for each time-point extraction.…”

Comparative genomics allows the discovery of cis -regulatory elements in mosquitoes

“…albimanus [CPIJ001358, AF281078, DQ442990, AY691327, respectively; present study, (27)]. GATA-binding factors are both positive and negative regulators of vitellogenesis (23,28), and discernible mRNA accumulation patterns are associated with distinct members of the GATA-motif family. For example, GATAAGAT and WGATWAGAT are enriched in An.…”

“…S1 and Table S1). Although sequence-based clustering defines putative CRE families, each of the 137 mosquito motifs was tested individually in subsequent analyses for association with genes that display similar expression profiles, because different members of a motif family may act as either activators or repressors of gene expression during reproductive development in mosquitoes (23,24).…”