Anti-termination of transcription within the long terminal repeat of HIV-1 by tat gene product

Nature. 1987 Dec 3-9;330(6147):489-93. doi: 10.1038/330489a0.

Abstract

Human immunodeficiency virus-1 (HIV-1) gene expression is controlled by cellular transcription factors and by virally encoded trans-activation proteins of the HIV-1 tat and art/trs genes, which are essential for viral replication. Tat trans-activates HIV-1 gene expression by interacting with the trans-acting response element (TAR) located within the HIV-1 long terminal repeat (LTR) (ref. 2). In transient expression assays, tat mediates its effects largely by increasing the steady-state levels of messenger RNA species that contain the TAR sequence at or near their 5' ends, suggesting a function for tat either in transcription or in subsequent RNA processing. The tat gene could also facilitate translation of mRNA containing the TAR sequence. To determine the mechanism of trans-activation by tat, we analysed the structure and rate of synthesis of RNA species directed by the HIV-1 LTR in transient expression assays both in the presence and absence of tat. Although the rate of HIV-1 transcription initiation was not affected by tat, transcriptional elongation beyond position +59 was seen only in the presence of tat. Thus, tat trans-activates HIV-1 transcription by relieving a specific block to transcriptional elongation within the TAR sequence.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetyltransferases / genetics
  • Cell Line
  • Chloramphenicol O-Acetyltransferase
  • Gene Products, tat
  • Genes, Viral*
  • HIV / genetics*
  • Nucleic Acid Hybridization
  • Oncogene Proteins, Viral / genetics
  • Plasmids
  • Protein Biosynthesis
  • RNA, Messenger / genetics
  • RNA, Viral / genetics
  • Repetitive Sequences, Nucleic Acid
  • Transcription Factors / genetics*
  • Transcription, Genetic*
  • Transfection
  • Virus Replication
  • tat Gene Products, Human Immunodeficiency Virus

Substances

  • Gene Products, tat
  • Oncogene Proteins, Viral
  • RNA, Messenger
  • RNA, Viral
  • Transcription Factors
  • tat Gene Products, Human Immunodeficiency Virus
  • Acetyltransferases
  • Chloramphenicol O-Acetyltransferase