Functional replacement of the HIV-1 rev protein by the HTLV-1 rex protein.
Two evolutionarily distinct families of human retroviruses, the human immunodeficiency viruses (HIV) and the human T-cell leukaemia viruses (HTLV), have been defined (reviewed in ref. 1). Although these virus groups share tropism for human CD4+ T cells, they differ markedly in primary sequence, genetic organization and disease association (AIDS versus adult T-cell leukaemia), but show similar general strategies for the regulation of viral gene expression. Each encodes a protein able to trans-activate transcription from the homologous viral long terminal repeat (tat in HIV, tax in HTLV), although these proteins act by different mechanisms and do not appear to be interchangeable. Each virus also produces a second trans-acting protein that induces the expression of the unspliced messenger RNAs encoding the viral structural proteins (rev in HIV and rex in HTLV). Here we show that the rex protein of HTLV-I can functionally replace the rev protein of HIV-1 in transient expression assays. This genetic complementation by rex is adequate for the rescue of a replication-defective rev mutant of HIV-1. This unexpected shared function between the structurally distinct rex and rev proteins emphasizes the importance of this highly conserved pathway for the regulation of human retrovirus gene expression.
Rimsky
L
L
Howard Hughes Medical Institute, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710.
Hauber
J
J
Dukovich
M
M
Malim
M H
MH
Langlois
A
A
Cullen
B R
BR
Greene
W C
WC
D005786:Gene Expression Regulation; D015694:Gene Products, rev; D005822:Genetic Vectors; D006678:HIV; D015486:HTLV-I Antigens / Q000494:pharmacology*; D015368:Human T-lymphotropic virus 1 / Q000378:metabolism*; D012191:Retroviridae Proteins / Q000494:pharmacology*; D015534:Trans-Activators; D014157:Transcription Factors / Q000494:pharmacology*; D014162:Transfection; D014764:Viral Proteins / Q000096:biosynthesis; D014779:Virus Replication; D054321:rev Gene Products, Human Immunodeficiency Virus
D015694:Gene Products, rev; D015486:HTLV-I Antigens; D012191:Retroviridae Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D014764:Viral Proteins; D054321:rev Gene Products, Human Immunodeficiency Virus