Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have reported recently the isolation of a cDNA for nuclear encoded subunit Vb of mouse cytochrome c oxidase by screening mouse bone marrow and kidney cDNA libraries. In the present study, this cDNA was used as a probe to screen a mouse genomic library and isolate the complete gene encoding subunit Vb. Southern blot hybridization of mouse genomic DNA with the cDNA probe suggested the occurrence of multiple genes including many retroinserts. Restriction analysis followed by Southern blot hybridization of genomic clones was used to identify the putative retroinserts from the intron containing genes. Of the 10 initial genomic clones isolated, one clone (MG3) showing the most complex hybridization pattern was found to contain the complete gene for subunit Vb. The DNA sequence analysis show that the subunit Vb gene contains four exons of 149, 73, 99, and 189 bases interrupted by three relatively small introns of 520, 165, and 648 nucleotides in a gene spanning about 2.5 kilobase pairs. As determined by a combination of primer extension and S1 protection analyses, the major transcription start site appears to be located 49 nucleotides upstream of the translation initiation codon. The ability of the 5' upstream DNA to initiate transcription was studied using the chloramphenicol acetyltransferase (CAT) expression plasmids in NIH 3T3 cells. Using this system we observed that a segment of the gene spanning nucleotides -574 to +45 can drive the transcription of CAT gene in an orientation dependent manner. The upstream region of subunit Vb gene lacks the TATA and CAAT elements, although it contains several GC rich elements and a pyrimidine rich stretch around the transcription start site.
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PMID:Structural organization of nuclear gene for subunit Vb of mouse mitochondrial cytochrome c oxidase. 165 32

We have isolated two overlapping clones covering the entire length of the gene of nuclear-encoded sub-unit IV of cytochrome c oxidase (COXIV) from a rat genomic library in Charon 4A and determined the structural organization of the gene. The gene spans approximately 7.0 kilobases and contains five exons interrupted by four introns. Of these exons, exon 2 codes for a whole length of the presequence of the rat COXIV precursor protein, while exons 3 to 5 encode three distinct structural domains of the mature protein. The 5'-flanking region of the gene lacks conventional TATA and CAAT boxes, but has a high G + C content and contains two putative binding sites for transcription factor SP1 and a sequence resembling the AP-4 responsive element. These results indicate that the promoter region of the rat COXIV gene possesses characteristic features common in housekeeping genes. The chloramphenicol acetyltransferase assay performed by constructing an improved phagemid, pBlueCAT3, revealed that a 773-base pair DNA fragment immediately preceding the cap site has a strong promoter activity. An octanucleotide sequence, -TTCTTGGT-, which is very close to the yeast HAP2/HAP3 responsive element, is located in the 5'-upstream region of the present gene.
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PMID:Structural organization of the rat cytochrome c oxidase subunit IV gene. 215 10

We have isolated two non-overlapping clones containing the genes for subunit Vb of cytochrome c oxidase (COXVb) from a rat genomic library in Charon 4A using a newly isolated full-length cDNA as a probe. One of the two genomic clones, designated as lambda COXVb741, contained a functional gene (COXVb-1), while the other one, designated as lambda COXVb211, contained an intronless processed pseudogene (COXVb-2). The COXVb-1 gene spans approximately 1.8 kb and consists of four exons interrupted by three introns. The nucleotide sequences of all exons are completely identical to the corresponding sequences of the rat liver and brain COXVb cDNAs, indicating that this gene is actually expressed. The 5'-flanking region of the gene lacks conventional TATA and CAAT boxes, but exhibits strong promoter activity in the chloramphenicol acetyltransferase (CAT) assay. Deletional analysis and gel shift assay of the 5'-flanking region suggested that the binding of nuclear factor Sp-1 could be essential for transcription of the gene. Southern blotting analysis implied the occurrence of multiple COXVb genes in the rat genome. However, the results of the present experiments suggest that only the COXVb-1 gene is expressed in rat tissues.
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PMID:Molecular cloning and characterization of the rat cytochrome c oxidase subunit Vb gene. 820 67

We have mapped the basal promoter activity of the mouse cytochrome c oxidase (COX) subunit Vb gene to the -17 to +20 region which contains two putative ets binding sites flanking an NF-E1 site fused to an Sp1 site. A 17-nucleotide sequence flanking the major transcription start site (-8 to +9), referred to as 17Inr (initiator sequence) was able to drive CAT activity in 3T3 cells to a level comparable to the construct containing sequences -17 to +20. This suggests that the 17Inr sequence contains the initiator activity. The 17Inr contains a pyrimidine-rich sequence, commencing with a CA that corresponds to the major transcription start site. Primer extension of RNA from transfected cells demonstrated that transcription initiation with the 17Inr template occurs at a site identical to the endogenous gene. DNA-protein binding by gel mobility shift and methylation interference analyses indicated that the pyrimidine-rich sequence immediately flanking the transcription start site consists of an NF-E1 factor binding motif with an overlapping upstream Sp1 binding site. A 13-nucleotide sequence, 13Inr (-4 to +9), which retains the NF-E1 binding activity but does not bind Sp1, was able to promote chloramphenicol acetyltransferase gene expression at levels similar to the 17Inr sequence, suggesting that NF-E1 factor binding is critical for initiator function. Finally, using an in vitro transcription system from Drosophila embryos we demonstrate that NF-E1 is necessary for transcription activation of both the 17Inr and the 13Inr initiator templates. Thus NF-E1 binding appears to be important for basal promoter function of the mouse COXVb gene.
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PMID:Identification of a transcriptional initiator element in the cytochrome c oxidase subunit Vb promoter which binds to transcription factors NF-E1 (YY-1, delta) and Sp1. 838 96