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)

A DNA fragment containing the tat, rev and env genes of the human immunodeficiency virus type 1 was inserted into the retroviral vector pZIPneoAU3. The resulting plasmid penvAU3 was transfected into HeLa and psi CRIP cells. Resulting recombinant retroviruses were used to infect HeLa and Jurkat cells. Immunoprecipitation analysis of stable transformants showed the expression of HIV env glycoproteins gp160, gp120 and gp41. Transactivation assays with a plasmid containing the gene for chloramphenicol acetyltransferase linked to HIV promoter-enhancer sequences demonstrated the expression of functional tat. These cells constitute virus-free tools for functional and structural studies of native env and tat.
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PMID:Human cell lines stably expressing HIV env and tat gene products. 254 12

A Sal I-Xho I fragment containing the genes encoding tat, art, and the envelope proteins from the BH10 clone of human immunodeficiency virus (HIV) was inserted into a simian virus 40 (SV40)-based eukaryotic expression vector. The vector is a shuttle vector that replicates to high copy numbers in both Escherichia coli and eukaryotic cells permissive for SV40 replication. Transfection of the HIV DNA-containing vector (pSVSX1) into the CV-1 monkey cell line gave high levels of expression of the envelope glycoproteins gp160 and gp120 in 20-30% of the transfected cells. By several criteria, the proteins were indistinguishable from those produced during infection. The proteins were localized to the cytoplasm and plasma membrane, and some of the gp120 was shed into the culture medium. Approximately 0.5 microgram of envelope protein could be extracted from 10(6) cells. This is at least 100 times higher than the levels found in HIV-infected H9 cells. In addition, a trans-activation assay performed with pSVSX1 and a plasmid containing the gene for chloramphenicol acetyltransferase under the control of the HIV long terminal repeat demonstrated that a functional tat gene product also was expressed. Thus, this transient vector system provides an abundant source of native envelope protein for purification and characterization and also will be useful for studies dealing with the regulation of HIV gene expression.
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PMID:Coexpression of human immunodeficiency virus envelope proteins and tat from a single simian virus 40 late replacement vector. 282 81

Endogenous sulphated polysaccharides such as heparin have been shown to inhibit the infectivity of HIV-1 min vitro. However, these naturally occurring polymers, due to extensive microheterogeneity within their structure, are difficult to characterise accurately. In contrast, dextrin can be chemically sulphated to produce a series of compounds sulphated in the 2-, 3-, or 6- position, or in all 3 positions, and the use of these compounds provides an opportunity to investigate the anti-HIV-1 activity of sulphated polysaccharides. The mechanisms whereby sulphated polysaccharides exert their anti-HIV-1 activity have not been fully elucidated. The interaction of recombinant HIV-1 proteins with sulphated polysaccharides was investigated using a biotinylated derivative of dextrin 2-sulphate (D2S) in a solid phase binding system. D2S was found to bind strongly to HIV-1 tat (EC50 = 0.10 microg/mL), less strongly to CD4 (EC50 = 0.33 microg/mL), weakly to HIV-1 vif and gp160, and not at all to HIV-1 gp120 or p24. Other sulphated derivatives of dextrin, i.e. dextrin 3-sulphate, dextrin 6-sulphate and dextrin 2,3,6-trisulphate, as well as heparin and dextran sulphate, were also shown to bind to HIV-1 tat, whereas the unsulphated compound dextrin did not. Binding studies using a series of overlapping peptides representing the complete sequence of HIV-1 tat revealed that D2S bound most strongly to the core domain of HIV-1 tat, although there was also binding to the cysteine-rich domain; both of these regions are important for HIV-1 tat function. In assessing function, HIV-1 tat-mediated transactivation was measured using H938 cells, a cell line that contains the HIV-LTR (long terminal repeat) promoter linked to a chloramphenicol acetyltransferase gene. D2S significantly inhibited HIV-1 tat transactivation in a dose-dependent manner (IC50 = 0.5 microg/mL), whereas dextrin had no effect. The interaction between D2S and HIV-1 tat provides a potential mechanism of HIV-1 inhibition whereby tat is sequestered and its transactivating activity abolished, effectively inhibiting the replication cycle.
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PMID:Interaction of the transactivating protein HIV-1 tat with sulphated polysaccharides. 1007 83