Two new regulatory elements controlling the Drosophila Sgs-3 gene are potential ecdysone receptor and fork head binding sites

Abstract

We identified two regulatory elements in the upstream region of the Drosophila Sgs-3 gene which are both able to bind the ecdysone receptor (EcR/USP) and the product of the fork head gene. Interestingly, only one of the EcR/USP binding sites is able to recognize in vitro-translated EcR/USP, which provides evidence for the existence of different receptor forms having different DNA binding specificities. Deletions of the elements lead to a reduced accumulation of Sgs-3 mRNA without altering the temporal expression profile of the gene. The data are consistent with the hypothesis that the ecdysone receptor directly contributes to the transcriptional activation of Sgs-3 by binding to at least one of the two elements. Since also the Sgs-4 gene is controlled by a functional EcR/USP binding site, a direct participation of EcR/USP in the formation of regulatory complexes may be of general importance for the hormonal control of Sgs genes.

Differential Expression of Genes in Uninfected and Rickettsia -Infected Dermacentor variabilis Ticks as Assessed by Differential-Display PCR

“…The gene encoding the SGS-3 protein has been described for several species of Diptera as having an ecdysone-responsive element. Levels of ecdysone control the level of transcription of Sgs-3 in Drosophila melanogaster in an inversely proportional manner (17). Because ecdysone has been described for ticks, it is expected that hormone response element genes are present in ticks (4), specifically in the reproductive tissues.…”

“…The Oi312-SGS-3 molecule was decreased in the ovaries and nearly abolished in the midguts and salivary glands of the Rickettsia-infected ticks. Although this transcript is likely under hormonal regulation, as are its paralogs in Drosophila (17), the significance of Rickettsia-mediated modulation is not clear. It is an exciting possibility that an unknown rickettsial receptor is in fact regulated either by this molecule or by the hormone.…”

Fork head and Sage maintain a uniform and patent salivary gland lumen through regulation of two downstream target genes,PH4αSG1andPH4αSG2

“…To test whether Fkh regulation of SG1 and SG2 is direct, we first asked if Fkh binds in vitro to the sequences in each enhancer that match published core Fkh-binding sites (Lehmann and Korge, 1996;Mach et al, 1996;Lehmann et al, 1997). Fkh bound strongly to site 'd' in the SG1 972 enhancer, as determined by electrophoretic mobility shift assays (EMSA) (Fig.…”

“…When we began our analysis of Fkh regulation of SG1 and SG2, we looked for every potential direct binding site within the SG1 and SG2 enhancers using data from three different studies (Lehmann and Korge, 1996;Mach et al, 1996;Lehmann et al, 1997), which revealed a seven bp core consensus Fkh-binding site. Although we found four such consensus sites within each enhancer, not all of the sites were bound by Fkh protein in vitro.…”

Functional regulation of glutamine:fructose-6-phosphate aminotransferase 1 (GFAT1) of Drosophila melanogaster in a UDP-N-acetylglucosamine and cAMP-dependent manner

“…In contrast to several of the Sgs genes, no ecdysoneresponse elements nor a forkhead-binding site were identified. The latter has been shown to be functional in the promoters of Sgs genes [31][32][33]. In close proximity to the TATAAA element, which also serves as a putative recognition site for binding of the B-factor, the Engrailed protein, TATA-box-binding protein (TBP), transcription factors TFIIB, TFIIα and TFIIFβ, and three putative GC boxes were identified ( Figure 5).…”