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

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

Comparative analysis of cosmid clones containing the human and feline c-sis genetic regions revealed the similar structural organization of these areas in the two species. The areas shared seven different genetic regions in and around the c-sis locus and of these was related to v-sis. Another region, 1.9 kbp in size and located about 8 kbp upstream of the v-sis homologous region in the human genome, also hybridized to the main c-sis transcriptional product of 3.5 kb. Comparison with a recently described c-sis cDNA clone (Collins et al., Nature 316, 748-750 (1985)) revealed that the 1.9 kbp DNA region contained a large 5' c-sis exon of at least 1050 bp. In this exon, the presumed initiation site of the predicted PDGF-2 containing precursor protein was located and appeared to be preceded by a large untranslated region. In the region immediately upstream of this exon, a TATA box and a consensus sequence for a potential Sp1 binding site were found at similar positions in both species. This region also exhibited promoter activity when tested in an assay in which coding sequences of bacterial chloramphenicol acetyltransferase (CAT; acetyl-CoA: chloramphenicol 3-O-acetyltransferase, EC 2.3.1.28) were placed under its control. The five other DNA regions were found upstream and downstream of the human c-sis transcription unit and also in an intron. Four of them contained repetitive sequences. Hybridization analysis of human and feline c-sis containing cosmid clones with a mixed synthetic nucleotide probe, which corresponded to sequences encoding amino acid residues 2-7 of chain 1 of platelet-derived growth factor (PDGF-1), suggested that the c-sis cosmid clones did not include PDGF-1-specific genetic sequences.
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PMID:Structure and nucleotide sequence of the 5' region of the human and feline c-sis proto-oncogenes. 300 95

In addition to Gag, Pol, and Env, primate lentiviruses encode other virion-associated proteins, including Vpr, Vpx, and Vif. Vpr- and Vpx-staphylococcal nuclease and chloramphenicol acetyltransferase fusion proteins incorporate into human immunodeficiency virus (HIV) virions and retain enzyme activity when expressed in trans with HIV proviruses (Wu et al., J. Virol. 69, 3389, 1995). To explore whether the viral protease (PR) could be expressed as a proteolytically active fusion protein, the HIV PR coding region was fused in-frame with the HIV-2 vpx and HIV-1 vpr genes. Using a vaccinia virus-T7 expression system, the Vpx-PR fusion protein was expressed and formed homodimers. Coexpression with Pr55Gag demonstrated that Vpx-PR possessed Gag-specific proteolytic activity and inhibited the production of Gag virus-like particles. Trans-expression of a PR-Vpr fusion protein with HIV-1 provirus caused a profound reduction in viral protein expression and virion production. Importantly, the PR-Vpr fusion protein caused a similar level of inhibition and intracellular cleavage of Pr55Gag precursor protein when coexpressed with protease defective HIV-1 provirus. The inhibitory effect of PR-Vpr expression on virion production was markedly greater than that of PR alone. These results indicate that Vpr arguments the intracellular proteolytic activity of PR when expressed as a fusion protein and thus may be relevant for the expression of PR in intracellular immunization strategies against HIV infection. Moreover, the ability to express and package enzymatically active PR-Vpr fusion protein, independent of Gag/Pol, may provide a novel means to study enzyme function.
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PMID:Proteolytic activity of human immunodeficiency virus Vpr- and Vpx-protease fusion proteins. 862 47

The reduction in levels of the potentially toxic amyloid-beta peptide (Abeta) has emerged as one of the most important therapeutic goals in Alzheimer's disease. Key targets for this goal are factors that affect the expression and processing of the Abeta precursor protein (betaAPP). Earlier reports from our laboratory have shown that a novel cholinesterase inhibitor, phenserine, reduces betaAPP levels in vivo. Herein, we studied the mechanism of phenserine's actions to define the regulatory elements in betaAPP processing. Phenserine treatment resulted in decreased secretion of soluble betaAPP and Abeta into the conditioned media of human neuroblastoma cells without cellular toxicity. The regulation of betaAPP protein expression by phenserine was posttranscriptional as it suppressed betaAPP protein expression without altering betaAPP mRNA levels. However, phenserine's action was neither mediated through classical receptor signaling pathways, involving extracellular signal-regulated kinase or phosphatidylinositol 3-kinase activation, nor was it associated with the anticholinesterase activity of the drug. Furthermore, phenserine reduced expression of a chloramphenicol acetyltransferase reporter fused to the 5'-mRNA leader sequence of betaAPP without altering expression of a control chloramphenicol acetyltransferase reporter. These studies suggest that phenserine reduces Abeta levels by regulating betaAPP translation via the recently described iron regulatory element in the 5'-untranslated region of betaAPP mRNA, which has been shown previously to be up-regulated in the presence of interleukin-1. This study identifies an approach for the regulation of betaAPP expression that can result in a substantial reduction in the level of Abeta.
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PMID:Phenserine regulates translation of beta -amyloid precursor protein mRNA by a putative interleukin-1 responsive element, a target for drug development. 1140 70