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 used derivatives of the recently developed stable transfection vector pALT-Neo to formally demonstrate that Leishmania enriettii contains the enzymatic machinery necessary for homologous recombination. This observation has implications for gene regulation, gene amplification, genetic diversity, and the maintenance of tandemly repeated gene families in the Leishmania genome as well as in closely related organisms, including Trypanosoma brucei. Two plasmids containing nonoverlapping deletions of the chloramphenicol acetyltransferase (CAT) gene, as well as the neomycin-resistance gene, were cotransfected into L. enriettii. Analysis of the DNA from these cells by Southern blotting and plasmid rescue revealed that a full-length or doubly deleted CAT gene could be reconstructed by homologous crossing-over and/or gene conversion between the two deletion plasmids. Additionally, parasites cotransfected with pALT-Neo and pALT-CAT-S, a plasmid containing two copies of the chimeric alpha-tubulin-CAT gene, resulted in G418-resistant parasites expressing high levels of CAT activity. The structure of the DNA within these cells, as shown by Southern blot analysis and the polymerase chain reaction, is that which would be expected from a homologous exchange event occurring between the two plasmids.
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PMID:Homologous recombination in Leishmania enriettii. 199 78

Interleukin-6 (IL-6) is a multifunctional cytokine that regulates both humoral and cellular immune responses. Accumulating evidence suggests that the infection of T cells and other cell types with human T-lymphotropic virus type 1 (HTLV-1) results in the constitutive expression of IL-6. However, the underlying molecular mechanisms are little understood. When a reporter plasmid, pIL6-CAT-E3, in which the human IL-6 enhancer/promoter region from -630 to +14 was linked to the bacterial chloramphenicol acetyltransferase (CAT) gene, was transfected, HTLV-1-infected but not -uninfected T-cell lines activated the IL-6 promoter. This indicated the presence of a factor transactivating the IL-6 gene in the infected cells. To evaluate the involvement of the HTLV-1-encoded transacting factor (Tax) in this transactivation, we examined the effect of transient cotransfection with the Tax-expression plasmid, pMAX-Neo, on the transcription from the IL-6 promoter by use of COS1 cells. The cotransfected COS1 has about six-times greater the CAT activity than that transfected with pIL6-CAT-E3 alone. The analysis of a series of deletions of the IL-6 promoter suggested that the region (-105/-47) containing a NF kappa B site was crucial for the Tax responsiveness. We further examined the effect of Tax on endogenous IL-6 gene expression using the Jurkat clone, JPX-9, stably transfected with pMAX-Neo. JPX-9 accumulated steady state transcripts of the endogenous IL-6 gene in response to the induction of Tax expression. Our findings indicate an important role of the Tax protein in the expression of IL-6 in cells infected with HTLV-1.
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PMID:Transactivation of the human interleukin-6 gene by human T-lymphotropic virus type 1 Tax protein. 806 47