Abstract
The TAt protein of the human immunodeficiency virus type 1 (HIV-1) activates the expression of viral mRNA through a cis-acting element in the LTR termed TAR. TAR RNA forms a stable stem-loop structure. Mutagenesis studies indicate that the stem structure, the primary sequence of the loop, and three unpaired bases in the stem (bulge) are important for Tat activation. Using the in vitro-transcribed TAR RNA as a probe, we have cloned a gene (TARBP-b) that encodes a TAR-binding protein from a cDNA expression library derived from Hut-78 cells. Expression of the 1.4-kb TARBP-b mRNA was observed in all mammalian cell lines tested. TARBP-b binds specifically to the bulge region of TAR RNA and trans-activates the HIV-1 long terminal repeat in the presence of ptat and prev expression plasmids. These results suggest that TARBP-b contributes to tat-mediated trans-activation.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Animals
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Base Sequence
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Cell Line
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Gene Expression Regulation, Viral / genetics
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Gene Products, rev / physiology
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Gene Products, tat / physiology
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Genes, Viral / genetics
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HIV Long Terminal Repeat / genetics
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HIV-1 / genetics*
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Humans
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Lymphocytes / virology
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Mice
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Molecular Sequence Data
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Nucleic Acid Conformation
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RNA Probes
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RNA, Messenger / biosynthesis
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RNA, Viral / chemistry
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RNA, Viral / metabolism*
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RNA-Binding Proteins / chemistry
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RNA-Binding Proteins / genetics*
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Sequence Analysis, DNA
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T-Lymphocytes / virology*
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Transcriptional Activation / genetics*
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rev Gene Products, Human Immunodeficiency Virus
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tat Gene Products, Human Immunodeficiency Virus
Substances
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Gene Products, rev
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Gene Products, tat
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RNA Probes
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RNA, Messenger
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RNA, Viral
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RNA-Binding Proteins
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rev Gene Products, Human Immunodeficiency Virus
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tat Gene Products, Human Immunodeficiency Virus
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trans-activation responsive RNA-binding protein