Human immunodeficiency virus Tat transactivation: induction of a tissue-specific enhancer in a nonpermissive cell line.
The enhancer of the human neurotropic papovavirus JC virus (JCV) restricts viral transcription to glial cells. We utilized the tissue specificity of the JCV enhancer as a tool to investigate the function of human immunodeficiency virus (HIV) Tat in transcriptional activation. The reporter plasmid pJCTAR-CAT was constructed by inserting the HIV type 1 Tat-responsive element, TAR, between the JCV promoter and the chloramphenicol acetyltransferase (CAT) gene. Cotransfection of pJCTAR-CAT and pSV-Tat, an expression vector for Tat, resulted in a 50-fold increase in JCV promoter activity in cells nonpermissive for JCV expression. Both the 98-bp JCV enhancer and the HIV TAR sequences were required for transactivation of pJCTAR-CAT in nonpermissive cells. The transactivation by Tat occurred at the level of transcription, as the increase in CAT activity paralleled an increase in the steady-state levels of CAT mRNA in S1 nuclease and nuclear run-on analyses. In the presence of Tat, the JCV enhancer is functional in cells normally nonpermissive for JCV expression; therefore, our results provide unique evidence that HIV type 1 Tat may regulate the activity of specific transcription factors.
Remenick
J
J
Laboratory of Molecular Virology, National Cancer Institute, Bethesda, Maryland 20892.
Radonovich
M F
MF
Brady
J N
JN
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002467:Cell Nucleus / Q000502:physiology; D004742:Enhancer Elements, Genetic; D015696:Gene Products, tat / Q000235:genetics / Q000378:metabolism*; D016325:HIV Long Terminal Repeat; D015497:HIV-1 / Q000235:genetics* / Q000378:metabolism; D006367:HeLa Cells / Q000502:physiology; D006801:Humans; D007577:JC Virus / Q000235:genetics*; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D011401:Promoter Regions, Genetic; D012367:RNA, Viral / Q000235:genetics; D015183:Restriction Mapping; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection; D054322:tat Gene Products, Human Immunodeficiency Virus
D015696:Gene Products, tat; D015345:Oligonucleotide Probes; D012367:RNA, Viral; D054322:tat Gene Products, Human Immunodeficiency Virus