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)

Antigen triggering of the T-cell receptor results in an accumulation of activated GTP-bound p21ras protein. To assess the role of ras protein in T-cell activation we have cotransfected the murine thymoma line EL4 with a construct capable of expressing a constitutively active, oncogenic form of Ha-ras and a reporter construct containing the human interleukin-2 promoter fused upstream of the bacterial gene for chloramphenicol acetyltransferase. We show that the ras oncoprotein contributes to interleukin-2 promoter activation. Its pattern of synergism with a calcium ionophore or the lymphokine interleukin-1 indicates that it replaces a signal mediated by protein kinase C. Interleukin-2 promoter activity in the presence of ras oncoprotein was inhibited by H7, a potent inhibitor of protein kinase C, but not by HA1004, an inhibitor of cyclic nucleotide-dependent kinase, suggesting that protein kinase C mediates the ras effect. In addition, we show that in these cells, expression of activated ras results in activation of a synthetic promoter containing several copies of an NF kappa B binding site.
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PMID:Interleukin-2 promoter activation in T-cells expressing activated Ha-ras. 153 20

Interference with T cell activation signals by Human immunodeficiency virus (HIV) gene products is suggested to contribute to the impairment of immune functions observed in AIDS. Interleukin-2 (IL-2) and HIV share common stimulatory signals triggered during T cell activation. The role of HIV tat, which is the main enhancing factor for viral LTR, in the regulation of IL-2 gene transcription has been studied following transient expression of the tat gene in phorbol ester and calcium ionophore-activated Jurkat cells transfected with IL-2 promoter-chloramphenicol acetyltransferase reporter constructs. We observed that tat increased the IL-2 promoter transcriptional activity in response to phorbol ester and ionomycin. This tat-dependent synergism mapped to the (-279 to -263 bp) NFAT motif of the IL-2 enhancer, which was sufficient to be transactivated by tat. Our data suggest that tat links T cell activating signals to the shared IL-2 and HIV regulation. This may play a role in the early phase of HIV infection.
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PMID:Human immunodeficiency virus type-1 tat enhances interleukin-2 promoter activity through synergism with phorbol ester and calcium-mediated activation of the NF-AT cis-regulatory motif. 799 66