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 photosynthetic non-sulphur bacterium Rhodospirillum rubrum contains a cluster of five genes encoding the subunits of F1-ATPase [Falk, Hampe & Walker (1985) Biochem. J. 228, 391-407]. Transcription of these genes has been studied by two methods, transcriptional mapping with S1 nuclease and primer extension analysis. Thereby a 5'-end in RNA derived from this region has been demonstrated at a guanine residue 236 bases before the initiation codon of the gene for the delta-subunit, the first in this cluster. DNA sequences on the 5' side of this nucleotide show some similarity to promoters in Escherichia coli, but are not apparently related to sequences upstream of the Rhodopseudomonas blastica atp operon. A 3'-end in RNA derived from this gene cluster has been demonstrated by S1-nuclease mapping. This is found before a run of thymidylate residues in the DNA, on the 3' side of a region of dyad symmetry. In E. coli these features are characteristic of rho-independent transcriptional termination signals. It appears from these studies and from the organization of the genes that the five genes in the atp cluster may be co-transcribed from this promoter and that transcripts terminate at the region of dyad symmetry.
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PMID:Transcription of Rhodospirillum rubrum atp operon. 286 16

We previously reported on the isolation of a new rat ATP binding cassette (ABC) transporter, ABCB6. We now report the isolation of the full-length cDNA and genomic clones containing the human ABCB6 gene. ABCB6 is 100% identical to the cloned MTABC3 human ABC transporter and contains the typical ABC signature, Walker A and B motifs. We found that HuABCB6 is expressed at low levels in normal human liver. We found that ABCB6 was overexpressed in human hepatocellular carcinomas compared to paired surrounding non-malignant tissue. We found that there was no difference in ABCB6 gene copy between human liver cancer and its paired non-malignant tissue. Because HuABCB6 was overexpressed in human cancers compared to peri-tumoral tissue in the absence of gene amplification, transcriptional regulation may play an important role in its expression. Therefore, we isolated a 14 kb genomic DNA clone containing the HuABCB6 promoter and 5'-flanking region. The 5'-flanking region contains a CpG island, lacks an appropriately positioned TATA element and contains a number of putative transcription factor binding sites. Two transcription start sites were identified by S1 nuclease mapping at -274 and -296 bp from the start codon. Transient transfection of the HuABCB6 promoter constructs (HuABCB6/1.68, 1.39, 1.13, 0.90, 0.52) containing the luciferase reporter gene resulted in a 1100-2300-fold increase in luciferase activity compared to the empty vector control whereas HuABCB6/1.68 subcloned in the reverse orientation resulted in no activity. We observed a significant decrease in luciferase activity with the promoter constructs, HuABCB6/0.25, 0.15 and 0.06, which indicates that an orientation-dependent functional promoter is contained within our previously predicted promoter region of -315 bp to -565 bp as deletion of this 250 bp sequence resulted in a loss of promoter activity.
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PMID:Isolation of a genomic clone containing the promoter region of the human ATP binding cassette (ABC) transporter, ABCB6. 1195 20