Synergistic activation of the human immunodeficiency virus type 1 promoter by the viral Tat protein and cellular transcription factor Sp1.
We have previously shown that the human immunodeficiency virus type 1 (HIV-1) Tat protein can activate a synthetic promoter containing consensus-binding sites for the cellular transcription factor Sp1. In this report, we show that a GAL-Tat fusion protein targeted via GAL4 DNA-binding sites can also trans activate an HIV-1 LTR promoter independently of the trans-activation response region. To show that the trans activation of the promoter by Tat directly involves the Sp1 protein, we have targeted a GAL-Sp1 fusion protein to the long terminal repeat promoter via upstream GAL4-binding sites. In the presence of Tat and GAL-Sp1, the promoter is synergistically trans activated at the transcriptional level, indicating that Tat and Sp1 functionally interact to trans activate the HIV-1 promoter. The Sp1 synergism is relatively specific, since another chimeric transcriptional activator, GAL-VP16, does not appear to be significantly synergistic with Tat.
Kamine
J
J
Institute for Molecular Virology, St. Louis University School of Medicine, Missouri 63110.
Chinnadurai
G
G
D001483:Base Sequence; D015696:Gene Products, tat / Q000235:genetics*; D015497:HIV-1 / Q000235:genetics*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000235:genetics; D016329:Sp1 Transcription Factor / Q000235:genetics*; D014158:Transcription, Genetic; D015533:Transcriptional Activation / Q000235:genetics*; D054322:tat Gene Products, Human Immunodeficiency Virus
D015696:Gene Products, tat; D011993:Recombinant Fusion Proteins; D016329:Sp1 Transcription Factor; D054322:tat Gene Products, Human Immunodeficiency Virus