HIV-1 Tat protein increases transcriptional initiation and stabilizes elongation

Laspia, M. F., Rice, A. P., Mathews, M. B. (October 1989) HIV-1 Tat protein increases transcriptional initiation and stabilizes elongation. Cell, 59 (2). pp. 283-92. ISSN 0092-8674

DOI: 10.1016/0092-8674(89)90290-0


We studied regulation of human immunodeficiency virus-1 (HIV-1) transcription by Tat and, for comparative purposes, by the adenovirus E1A protein. These two trans-activators exerted different effects. Two classes of HIV-1-promoted cytoplasmic RNA were detected, one class corresponding to full-length transcripts and the other to transcripts ending 55 and 59 nucleotides from the transcription start. Tat increased the level of the full-length class only, whereas E1A increased the levels of both classes of RNA. We also measured the effects of Tat and E1A on RNA synthesis rates. Without trans-activators, HIV-1-directed transcription was relatively weak and exhibited a marked polarity. Both Tat and E1A dramatically increased promoter-proximal transcription, while only Tat suppressed transcriptional polarity. Mutations in the TAR element did not influence basal transcription rates or the response to E1A, but eliminated trans-activation by Tat. We propose that Tat acts through TAR to increase initiation complex formation on the HIV-1 promoter and to stabilize complexes during elongation.

Item Type: Paper
Uncontrolled Keywords: Adenovirus Early Proteins Adenoviruses, Human/genetics Comparative Study DNA-Binding Proteins/metabolism DNA-Directed RNA Polymerases/metabolism Gene Expression Gene Products, tat/*metabolism Genes, Viral HIV-1/*genetics Hela Cells/metabolism Humans Models, Genetic Mutation Oncogene Proteins, Viral/metabolism Plasmids RNA, Viral/genetics Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S. Restriction Mapping Trans-Activators/*metabolism *Transcription, Genetic
Subjects: diseases & disorders > viral diseases > HIV
CSHL Authors:
Communities: CSHL labs
Depositing User: Gail Sherman
Date: 20 October 1989
Date Deposited: 28 Jun 2017 20:00
Last Modified: 28 Jun 2017 20:00
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