Requirement of the human immunodeficiency virus type 1 env gene sequence for TAR-independent trans activation by Tat from the major immediate-early promoter of murine cytomegalovirus.
Previously it has been demonstrated that the human immunodeficiency virus type 1 (HIV-1) Tat protein mediates induction of the HIV-1 env expression through a TAR-independent manner in heterologous and homologous promoter systems (Kim and Risser, 1993, J. Virol. 67, 239; Kim and Panganiban, 1993, J. Virol. 67, 3739). To further explore the transactivation of HIV-1 env gene, I examined expression of the env, the bacterial CAT, and the firefly luciferase genes from a heterologous promoter, the major immediate-early promoter (MIEP) of murine cytomegalovirus (MCMV). Here we show that Tat augments gene expression from the MCMV MIEP only when linked to the env gene. Surprisingly, in contrast to the expression from an HIV-1 LTR lacking the TAR element, TAR-independent transactivation of env gene expression from MCMV MIEP did not require the full length Tat protein. In addition, deletion of the previously identified cis-acting Tat-responsive element in env did not affect Tat transactivation of the env gene expression. Thus, there are multiple distinct elements that mediate Tat responsiveness in the absence TAR.
Kim
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McArdle Laboratory for Cancer Research, University of Wisconsin, Madison, 53706.
D001426:Bacterial Proteins / Q000494:pharmacology; D001483:Base Sequence; D002628:Chemoreceptor Cells; D003587:Cytomegalovirus / Q000235:genetics*; D029968:Escherichia coli Proteins; D015870:Gene Expression; D015696:Gene Products, tat / Q000494:pharmacology*; D015752:Genes, env; D015497:HIV-1 / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics*; D008565:Membrane Proteins / Q000494:pharmacology; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011956:Receptors, Cell Surface; D012091:Repetitive Sequences, Nucleic Acid; D015533:Transcriptional Activation; D054322:tat Gene Products, Human Immunodeficiency Virus
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D015696:Gene Products, tat; D017874:Immediate-Early Proteins; D008565:Membrane Proteins; D011956:Receptors, Cell Surface; C057331:Tar protein, E coli; D054322:tat Gene Products, Human Immunodeficiency Virus