The octamer-binding proteins Oct-1 and Oct-2 repress the HIV long terminal repeat promoter and its transactivation by Tat.
Although the HIV-1 long terminal repeat (LTR) contains four potential binding sites for the octamer-binding protein, Oct-1, which is known to interact with the HIV-1 Tat protein, the effect of the Oct-1 factor on HIV LTR-driven gene expression has not previously been reported. We show here that both Oct-1, and to a lesser extent the related Oct-2 protein, can repress both the basal activity of the HIV-1 LTR and its transactivation by Tat. These effects are still observed with an HIV LTR construct containing only a single octamer-binding site located between the TATA box and the transcriptional start site. The stronger inhibitory effect of Oct-1 on both these promoters is dependent upon its C-terminal region which cannot be effectively replaced by the equivalent region of Oct-2. These effects are discussed in terms of the regulation of HIV LTR activity in different cell types and in response to T-cell activation.
Liu
Y Z
YZ
Department of Molecular Pathology, University College London Medical School, U.K.
Latchman
D S
DS
D004268:DNA-Binding Proteins / Q000502:physiology*; D015696:Gene Products, tat / Q000235:genetics / Q000502:physiology*; D016325:HIV Long Terminal Repeat / Q000187:drug effects; D015497:HIV-1 / Q000235:genetics*; D006367:HeLa Cells; D051863:Host Cell Factor C1; D006801:Humans; D050811:Octamer Transcription Factor-1; D050813:Octamer Transcription Factor-2; D011401:Promoter Regions, Genetic / Q000187:drug effects; D012097:Repressor Proteins / Q000502:physiology*; D014157:Transcription Factors / Q000502:physiology*; D015533:Transcriptional Activation / Q000187:drug effects; D054322:tat Gene Products, Human Immunodeficiency Virus
D004268:DNA-Binding Proteins; D015696:Gene Products, tat; C497692:HCFC1 protein, human; D051863:Host Cell Factor C1; D050811:Octamer Transcription Factor-1; D050813:Octamer Transcription Factor-2; C494165:POU2F1 protein, human; C058435:POU2F2 protein, human; D012097:Repressor Proteins; D014157:Transcription Factors; D054322:tat Gene Products, Human Immunodeficiency Virus