Alternative pathway for induction of human immunodeficiency virus gene expression: involvement of the general transcription machinery.
Human immunodeficiency virus type 1 (HIV-1) is viable and mitogen inducible in the absence of its binding sites for the inducible transcription factor NF-kappa B. We have investigated alternative mechanisms for induction of HIV-1 transcription. Using transient transfection assays, we found that transcription from an HIV-1 LTR containing mutant kappa B sites was activated 10- to 20-fold in a variety of human cell types by the phorbol ester phorbol myristate acetate (PMA). The promoter elements conferring this inducibility were localized to the region downstream of nucleotide -70, which contains the TATA and TAR elements and binding sites for transcription factors Sp1 and LBP-1. Synthetic promoters containing only Sp1 sites and a TATA element were also induced in transfection experiments as well as in in vitro transcription experiments with T-cell nuclear extracts. Moreover, promoters containing a TATA box in the absence of Sp1 sites or Sp1 sites in the absence of a TATA box were equally inducible in vitro, as was an RNA polymerase III promoter. The activities of RNA polymerases II and III and of the 38-kDa TATA-binding protein transcription factor IID (TFIID), were not induced by PMA, but electrophoretic mobility shift assays revealed a highly inducible protein-DNA complex that interacted specifically with the TATA sequence. This protein-DNA complex appeared to be much larger than that found with the 38-kDa human TFIID expressed in bacteria. Taken together, these data suggest that a component of the general transcription machinery, and possibly a TFIID-associated protein, is induced in T cells by PMA.(ABSTRACT TRUNCATED AT 250 WORDS)
Sakaguchi
M
M
Division of Hematology/Oncology, New England Deaconess Hospital, Boston, Massachusetts.
Zenzie-Gregory
B
B
Groopman
J E
JE
Smale
S T
ST
Kim
S Y
SY
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D002872:Chromosome Deletion; D015967:Gene Expression Regulation, Viral; D016325:HIV Long Terminal Repeat; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism; D015345:Oligonucleotide Probes; D016385:TATA Box; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D035362:Transcription Factor TFIID; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection
D016328:NF-kappa B; D015345:Oligonucleotide Probes; D035362:Transcription Factor TFIID; D014157:Transcription Factors; D015500:Chloramphenicol O-Acetyltransferase; D013755:Tetradecanoylphorbol Acetate