Identification and characterization of a HeLa nuclear protein that specifically binds to the trans-activation-response (TAR) element of human immunodeficiency virus.
Human immunodeficiency virus type 1 RNAs contain a sequence, trans-activation-response (TAR) element, which is required for tat protein-mediated trans-activation of viral gene expression. We have identified a nuclear protein from extracts of HeLa cells that binds to the TAR element RNA in a sequence-specific manner. The binding of this 68-kDa polypeptide was detected by UV cross-linking proteins to TAR element RNA transcribed in vitro. Competition experiments were performed by using a partially purified preparation of the protein to quantify the relative binding affinities of TAR element RNA mutants. The binding affinity of the TAR mutants paralleled the reported ability of those mutants to support tat trans-activation in vivo. We propose that this cellular protein moderates TAR activity in vivo.
Marciniak
R A
RA
Center for Cancer Research, Massachusetts Institute of Technology, Cambridge.
Garcia-Blanco
M A
MA
Sharp
P A
PA
D001483:Base Sequence; D001665:Binding Sites; D001667:Binding, Competitive; D006678:HIV / Q000235:genetics*; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000302:isolation & purification / Q000378:metabolism* / Q000528:radiation effects; D009690:Nucleic Acid Conformation; D015345:Oligonucleotide Probes; D010957:Plasmids; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D015183:Restriction Mapping; D015533:Transcriptional Activation; D014466:Ultraviolet Rays
D009687:Nuclear Proteins; D015345:Oligonucleotide Probes; D012367:RNA, Viral