Steroidogenic factor-1 binding and transcriptional activity of the cholesterol side-chain cleavage promoter in rat granulosa cells.
The cholesterol side-chain cleavage cytochrome P450 (CYP11A; P450scc) gene is expressed in rat ovarian follicles in response to gonadotropins (FSH/LH) and cAMP. To identify functional regions within the rat P450scc promoter, 894 basepairs (bp) of 5'-flanking sequence and 5'-deletions (at -379, -101, -73, and -38 bp) were linked to the human GH reporter gene and transfected into cultured rat granulosa cells. cAMP inducibility of the rat promoter was localized to a region (between -73/-38 bp) that contains one of two AGGT/CC/TA motifs, designated SCC1 (-51/-43 bp) and SCC2 (-79/-71 bp), within the rat promoter. One of the nuclear proteins in granulosa cells that binds to SCC1 was identified as the orphan receptor, steroidogenic factor-1 (SF-1). In contrast, multiple protein-DNA complexes formed with SCC2, only one of which was clearly identified as SF-1. Nuclear extract binding was sequence specific; SCC1 bound SF-1 more strongly than did SCC2. Thus, the two AGGT/CC/TA motifs of the rat promoter appear to differ structurally and functionally. Furthermore, because the expression of SF-1 mRNA precedes hormonal/cAMP induction of P450scc mRNA and is not regulated in vitro by cAMP, the functional role of SF-1 in transcriptional regulation of the P450scc gene, including its induction by cAMP, is not entirely clear and is probably dependent on other factors and/or the modification (phosphorylation?) of SF-1.
Clemens
J W
JW
Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030.
Lala
D S
DS
Parker
K L
KL
Richards
J S
JS
D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000235:genetics* / Q000378:metabolism; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000502:physiology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D051717:Fushi Tarazu Transcription Factors; D006107:Granulosa Cells / Q000378:metabolism*; D018398:Homeodomain Proteins; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D054339:Steroidogenic Factor 1; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D051717:Fushi Tarazu Transcription Factors; D018398:Homeodomain Proteins; C515057:NR5A1 protein, human; D009687:Nuclear Proteins; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D054339:Steroidogenic Factor 1; D014157:Transcription Factors; C515060:steroidogenic factor 1, rat; D005576:Colforsin; D000242:Cyclic AMP; D002786:Cholesterol Side-Chain Cleavage Enzyme