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Ecdysone regulation of the Drosophila Sgs‐4 gene is mediated by the synergistic action of ecdysone receptor and SEBP 3.
Author(s) -
Lehmann M.,
Korge G.
Publication year - 1995
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1995.tb07050.x
Subject(s) - ecdysone , biology , psychological repression , ecdysone receptor , gene , genetics , microbiology and biotechnology , gene expression , nuclear receptor , transcription factor
The steroid hormone 20‐hydroxyecdysone controls both induction and repression of the Drosophila ‘intermolt gene’ Sgs‐4. We show here that the ecdysone receptor binds to two sites, element I and element II, in the regulatory region of Sgs‐4. A functional analysis revealed that element II appears to be of no importance for Sgs‐4 expression, while element I proved to be an ecdysone response element that is necessary, but not sufficient, for induction of Sgs‐4 expression. Our results provide no evidence that repression of Sgs‐4 expression is mediated by one of the two receptor binding sites. In the close vicinity of elements I and II, we detected two binding sites of secretion enhancer binding protein 3 (SEBP 3). Like receptor element I, one of these sites also proved to be necessary, but not sufficient, for expression of Sgs‐4. Therefore, induction of Sgs‐4 requires binding of both ecdysone receptor and SEBP 3 to a complex hormone response unit, which also contains binding sites for a third factor, SEBP 2. The SEBP 2 sites coincide with binding sites of products of the Broad‐Complex locus, which has been implicated recently with transduction of the hormonal signal. Thus, the available data suggest that induction of Sgs‐4, and possibly other ‘intermolt genes’, is a combination of a primary and a secondary response to the hormone.