Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The upstream region of the rat CYP17 gene shows significant homology to the upstream regions of the bovine and human genes, 53 and 60 percent, respectively. The start site of transcription was determined by primer extension and S1 nuclease protection to be 41 base pairs (bp) upstream of the initiating methionine codon. Expression vectors were constructed by ligation of upstream sequences into promoterless chloramphenicol acetyl transferase (CAT) vectors. Transient transfection studies using primary cultures of rat Leydig cells indicate a strong cAMP-responsive element located within the -26/+65 region. Stimulation by cyclic AMP was abolished when sequences upstream of -264 were included in expression vectors. No significant expression was seen in Leydig cells in the absence of dbcAMP nor was there any expression in the presence or absence of dbcAMP in rat skin fibroblasts or in mouse adrenal (Y-1) cells in which CYP17 is not normally expressed. Three possible regulatory elements were found in the 5' upstream region: a CRE/ATF consensus sequence (GACGTCA) starting at position -57; a GRE consensus sequence (TGTTCT) starting at position -501; and a consensus sequence for AP-1 binding (TTAGTCA) starting at position -659. It was concluded that the CRE/ATF at -57 is not responsible for increased transcription in the presence of cyclic AMP.
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PMID:Cyclic AMP regulates expression of the rat gene for steroid 17 alpha-hydroxylase/C17-20 lyase P-450 (CYP17) in rat Leydig cells. 132 85

Expression of the gene encoding cytochrome P450 17alpha-hydroxylase, CYP17, is necessary for adrenal and gonadal steroidogenesis in most species. However, some animals, such as the pig, express CYP17 in the trophectoderm of the preattachment blastocyst, an event associated with estrogen synthesis and the establishment of pregnancy. How trophoblastic expression of CYP17 is regulated in the porcine blastocyst remains unknown and forms the basis of the following studies. The porcine CYP17 gene, including the complete coding and several kilobases of 5'-flanking regions, was cloned and sequenced. Blastocysts were examined by Northern analysis to verify the level of CYP17 transcript, and tissue-specific expression in the trophectoderm was confirmed by in situ hybridization. Primer extension, S1 nuclease protection, and 5'-rapid amplification of cDNA ends confirmed a common proximal transcription start site in adrenals and gonads (-48 bp) but identified a unique distal start site used in porcine trophectoderm (-182 bp). Additionally, reporter analysis of the CYP17 regulatory region demonstrated that constructs (-27 to -718 bp) were unresponsive to forskolin when expressed in porcine trophoblast cells, suggesting that trophoblast may not be able to respond to cAMP induction of this gene. The identification of this distal, previously undescribed, transcriptional start site suggests that unique mechanisms control the expression of CYP17 in porcine trophectoderm and possibly other genes important in implantation and early placental development.
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PMID:Unique regulation of CYP17 expression in the trophectoderm of the preattachment porcine blastocyst. 992 87