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)

Transcription of the cytoskeletal beta-actin gene is rapidly induced by phorbol 12-myristate 13-acetate (PMA) and the calcium ionophore, A23187, in cultured H4IIE hepatoma (H4) cells. PMA directly activates protein kinase C (PKC) and activation of PKC is necessary for the cellular actions of PMA, including induction of beta-actin gene transcription. In the present study, we determined the DNA sequence requirements for induction of the beta-actin gene by PMA and A23187. Constructs containing progressive deletions of normal and mutated human beta-actin 5' sequences fused to the reporter gene, bacterial chloramphenicol acetyltransferase, were analysed in transient transfections of H4 cells. We delineated the PMA response DNA element of the human beta-actin gene to the proximal CCArGG box (-62 to -53) in the 5' flanking region. In contrast, A23187 did not induce expression of transfected gene constructs containing this CCArGG box. Additionally, we demonstrated that CCArGG boxes from two other PMA-induced genes in H4 cells, c-fos and gamma-actin, could confer PMA inducibility to a heterologous promoter. This CCArGG box specifically interacts with one or more proteins present in nuclear extracts of H4 cells. These results indicate that in cultured cells, PMA-dependent induction of the beta-actin gene is mediated through the proximal CCArGG box. This suggests that the CCArGG box is a target for PKC action and may be involved in the control of other PKC regulated genes.
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PMID:Identification of beta-actin sequences necessary for induction by phorbol esters and calcium ionophores. 818 67

The protein kinase inhibitor 2-aminopurine (2-AP) greatly stimulated expression in human promonocytes-macrophages of plasmid constructs carrying various reporter genes (chloramphenicol acetyltransferase, lacZ, firefly luciferase [luc], and Salmonella typhimurium histidinol dehydrogenase [his]) driven by the human immunodeficiency virus type 1 (HIV-1) long terminal repeat. Adenine, adenosine, and caffeine were also effective inducers, but other purine or pyrimidine derivatives were ineffective. Experiments with mutant derivatives of the HIV-1 long terminal repeat revealed no specific eukaryotic promoter elements necessary for 2-AP induction but indicated the need for some minimum combination of such elements. Induction of HIV-1-directed gene expression appeared not to require action of the transcription factor NF-kappa B. The mechanism of induction was investigated by using the luc and his genes linked to the HIV-1 long terminal repeat. 2-AP induced marked, steady rises in mRNA accumulation from both transfected and chromosomally integrated HIV-1 constructs but no increases from an endogenous gene encoding gamma-actin or glucose 6-phosphate dehydrogenase. Thus, induction is selective and not an artifact induced by transfecting DNA into cells. In run-on transcription experiments, the rates of transcription initiation of both transfected and integrated copies of the his gene increased about sixfold in cells treated with 2-AP. Thus, while increased initiation accounted for a portion of 2-AP induction, it could not cause the far greater increase in steady-state mRNA levels. 2-AP induction did not change mRNA decay rates and differed from the phorbol ester (phorbol myristate acetate)-induced activation of the protein kinase C-NF-kappa B pathway in its time course and in its requirement for new protein synthesis. Gel retardation assays showed that unlike phorbol myristate acetate induction, 2-AP induction is enhancer independent. Whereas many previous studies have implicated the activation of various protein kinases in gene induction, we here describe a mechanism of gene activation that appears to involve protein kinase inhibition as a component of the induction response.
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PMID:Inducible transcriptional activation of the human immunodeficiency virus long terminal repeat by protein kinase inhibitors. 835 80