Interactions of the Oct-1 POU subdomains with specific DNA sequences and with the HSV alpha-trans-activator protein.
Trans-activation by the herpes simplex virus (HSV) protein, alpha TIF (VP16), is dependent on an inducible enhancer sequence that contains a homolog of the octamer element. An ordered series of multiprotein complexes can be assembled on this enhancer, requiring the interactions of Oct-1, alpha TIF, and two additional cellular factors (C1 and C2). Oct-1 binds to the octamer homolog, whereas alpha TIF, also a sequence-specific DNA-binding protein, recognizes sequences within the HSV enhancer core. The partially purified C1 factor interacts directly with alpha TIF in the absence of DNA and is required to form a stabile Oct-1/alpha TIF/C1 factor complex. The POU domain of Oct-1 is a bipartite sequence recognition structure, as both the POU-specific box and the POU homeo box contribute directly to the recognition of the octamer element. Surprisingly, the POU homeo box alone is sufficient to direct the cooperative binding of alpha TIF and to assemble the Oct-1/alpha TIF/C1 factor complex.
Kristie
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Center for Cancer Research, Massachusetts Institute of Technology, Cambridge 02139.
Sharp
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PA
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002846:Chromatography, Affinity; D004268:DNA-Binding Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004742:Enhancer Elements, Genetic; D005801:Genes, Homeobox; D006561:Herpes Simplex / Q000235:genetics*; D017405:Herpes Simplex Virus Protein Vmw65; D051863:Host Cell Factor C1; D008969:Molecular Sequence Data; D005810:Multigene Family; D050811:Octamer Transcription Factor-1; D015534:Trans-Activators / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D015533:Transcriptional Activation; D014764:Viral Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
D004268:DNA-Binding Proteins; D017405:Herpes Simplex Virus Protein Vmw65; D051863:Host Cell Factor C1; D050811:Octamer Transcription Factor-1; D015534:Trans-Activators; D014157:Transcription Factors; D014764:Viral Proteins