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

To analyze the mechanism of the cell type-specific expression of protein kinase C beta (PKC beta), we isolated the 5'-portion of the human gene for PKC beta and identified multiple positive and negative regulatory sequences that regulate its transcription. S1 nuclease mapping as well as primer extension analysis of the 5'-end of the PKC beta mRNA identified a putative transcriptional initiation site (position +1) 484 base pairs (bp) upstream of the first ATG codon. The 5'-upstream sequence contains a CCAAT sequence at position -110, but no TATA box. The transcriptional activities of various 5'-deletion mutants of the PKC beta gene upstream region, fused to the chloramphenicol acetyltransferase structural gene, were examined in terms of chloramphenicol acetyltransferase expression after transfection into three kinds of rodent cell lines: P19 and GH4C1, which are positive for the expression of PKC beta mRNA; and 3Y1, which is negative. Mutants containing a 5'-flanking sequence longer than 1.9 kilobases (kb) showed chloramphenicol acetyltransferase activities of the same order as the expression of the endogenous gene. This indicates that this region contains sequences regulating the cell-type specificity of PKC beta gene expression and that the specificity is determined at least partially at the level of transcription. The 1.9-kb sequence contains at least three positive elements: P1 (-56 to -234 bp), P2 (-234 to -411 bp), and PN (-1.4 to -1.9 kb). PN is active only in P19 cells, P1 in GH4C1 and P19 cells, and P2 in all three cell lines. In addition to these positive elements, there are negative elements: N1 (-411 to -674 bp), which is active in all three cell lines; and PN, which is active only in GH4C1 cells. These results suggest the presence of multiple trans-acting factors that act on these positive and negative cis-acting elements and regulate the cell type-specific expression of the PKC beta gene.
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PMID:Positive and negative regulation of the transcription of the human protein kinase C beta gene. 155 24

Protein kinase C (PKC) serine/threonine kinases transduce cellular signals initiated by phospholipase C activation and diacylglycerol production. Human gene sequences from the beta and gamma isoforms were cloned and sequenced, and transcriptional regulation was studied. The major PKC beta transcription initiation site was identified by primer extension and S1 nuclease protection. Additional transcription initiation sites were located within a CpG-rich region proximal to the ATG. The transcription initiation site of the PKC gamma gene was identified by primed cDNA synthesis. In transfection experiments, the PKC gamma promoter was expressed at high level in U937 and HL60 cells but not in COS-1 cells. A sequence motif (AnAGATTCanAGAGnCa), reiterated over at least 1 kb, was located approximately 1.5 kb 5' of the PKC gamma translation initiation codon. This repetitive motif is abundant in run-on RNA in the hematopoietic and epithelial cell lines tested. Analysis of promoter deletion constructs by transient transcription assays in U937, IM9, and COS-1 cells showed negative regulation of the PKC beta promoter by sequences located between -3,000 and -690. although no homology between PKC beta and PKC-gamma 5'-flanking sequences was observed, both PKC beta and PKC gamma promoters were potently induced by 12-phorbol 13-myristate in transfected U937 cells.
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PMID:Autoregulation of cloned human protein kinase C beta and gamma gene promoters in U937 cells. 788 Apr 42

Protein kinase C-eta (PKC-eta) is predominantly expressed in epithelial tissue, including lung, intestine, and skin. In skin, PKC-eta expression is limited to keratinocytes in the upper layers of the epidermis. To investigate regulation of cell type-specific expression of PKC-eta, we cloned the 5'-segment of the PKC-eta gene from a P1 genomic library. A 9.4-kilobase pair fragment encompassing the 5'-flanking region, first exon, and first intron, was localized on human chromosome 14 (14q22-23). Two major transcription initiation sites identified by reverse transcriptase polymerase chain reaction, primer extension, and S1 nuclease mapping, were located approximately 650 base pairs upstream from the translation start site. The human PKC-eta proximal promoter region lacks canonical TATA and CAAT boxes and GC-rich regions. A 1.6-kilobase pair 5'-flanking region displayed maximal promoter activity. This promoter was active in human keratinocytes but not human skin fibroblasts, in accord with endogenous PKC-eta gene expression. Stepwise 5' deletion analysis revealed the presence of adjacent regulatory regions containing silencer and enhancer elements located 1821-1702 base pairs and 1259-1189 base pairs upstream of the transcription initiation site. Deletion of the proximal PKC-eta promoter rendered the enhancer element inactive. Both the silencer and enhancer elements regulated heterologous promoters in keratinocytes but not fibroblasts. Electrophoretic mobility shift analysis demonstrated specific protein binding to Ets/heat shock factor and Ets/activator protein-1 consensus sequences in the enhancer and silencer regions, respectively. Mutations of the Ets/heat shock factor binding sites caused loss of functional enhancer activity. These data elucidate transcriptional regulation and tissue-specific expression of the PKC-eta gene.
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PMID:Cloning and characterization of the human protein kinase C-eta promoter. 1049 22