HIV-1 Tat protein increases transcriptional initiation and stabilizes elongation.

摘要: We studied regulation of human immunodeficiency virus-1 (HIV-1) transcription by Tat and, for comparative purposes, the adenovirus E1A protein. These two trans-activators exerted different effects. Two classes HIV-1-promoted cytoplasmic RNA were detected, one class corresponding to full-length transcripts and other ending 55 59 nucleotides from start. increased level only, whereas levels both RNA. also measured effects on synthesis rates. Without trans-activators, HIV-1-directed was relatively weak exhibited a marked polarity. Both dramatically promoter-proximal transcription, while only suppressed transcriptional Mutations in TAR element did not influence basal rates or response E1A, but eliminated trans-activation Tat. propose that acts through increase initiation complex formation HIV-1 promoter stabilize complexes during elongation.