Transcriptional cofactor CA150 regulates RNA polymerase II elongation in a TATA-box-dependent manner.
Tat protein strongly activates transcription from the human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) by enhancing the elongation efficiency of RNA polymerase II complexes. Tat-mediated transcriptional activation requires cellular cofactors and specific cis-acting elements within the HIV-1 promoter, among them a functional TATA box. Here, we have investigated the mechanism by which one of these cofactors, termed CA150, regulates HIV-1 transcription in vivo. We present a series of functional assays that demonstrate that the regulation of the HIV-1 LTR by CA150 has the same functional requirements as the activation by Tat. We found that CA150 affects elongation of transcription complexes assembled on the HIV-1 promoter in a TATA-box-dependent manner. We discuss the data in terms of the involvement of CA150 in the regulation of Tat-activated HIV-1 gene expression. In addition, we also provide evidence suggesting a role for CA150 in the regulation of cellular transcriptional processes.
Suñé
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Departments of Pharmacology and Cancer Biology, Levine Science Research Center, Duke University Medical Center, Durham, North Carolina 27710, USA.
Garcia-Blanco
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MA
D002461:Cell Line, Transformed; D004268:DNA-Binding Proteins / Q000235:genetics; D015967:Gene Expression Regulation, Viral; D015696:Gene Products, tat / Q000378:metabolism; D016325:HIV Long Terminal Repeat; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D011401:Promoter Regions, Genetic; D012319:RNA Polymerase II / Q000378:metabolism*; D016385:TATA Box; D035181:TATA-Box Binding Protein; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics; D014158:Transcription, Genetic; D035602:Transcriptional Elongation Factors; D054322:tat Gene Products, Human Immunodeficiency Virus
D004268:DNA-Binding Proteins; D015696:Gene Products, tat; D035181:TATA-Box Binding Protein; C108440:TCERG1 protein, human; D015534:Trans-Activators; D014157:Transcription Factors; D035602:Transcriptional Elongation Factors; D054322:tat Gene Products, Human Immunodeficiency Virus; D012319:RNA Polymerase II