The Oct-1 POU domain mediates interactions between Oct-1 and other POU proteins.
The POU domain is the conserved DNA binding domain of a family of gene regulatory proteins. It consists of a POU-specific domain and a POU homeodomain, connected by a variable linker region. Oct-1 is a ubiquitously expressed POU domain transcription factor. It binds to the canonical octamer sequence (ATGCAAAT) as a monomer. Here we show by chemical cross-linking and protein affinity chromatography that the Oct-1 POU domain monomers can interact in solution. This association requires both the POU homeodomain and the POU-specific domain. The interaction is transient in solution and can be stabilized by binding to the heptamer-octamer sequence in the immunoglobulin heavy-chain promoter. This correlates with cooperative DNA binding to this site. POU proteins from different subclasses, including Oct-1, Oct-2A, Oct-6, and a chimeric Oct-1 protein containing the Pit-1 POU domain, can bind cooperatively to a double binding site and form a heteromeric complex.
Laboratory for Physiological Chemistry, University of Utrecht, The Netherlands.
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Verrijzer
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van Oosterhout
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van der Vliet
D001483:Base Sequence; D001665:Binding Sites; D002845:Chromatography; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005801:Genes, Homeobox / Q000235:genetics; D005982:Glutathione Transferase / Q000235:genetics; D006367:HeLa Cells; D051863:Host Cell Factor C1; D006801:Humans; D015151:Immunoblotting; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007700:Kinetics; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D050811:Octamer Transcription Factor-1; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011994:Recombinant Proteins / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014616:Vaccinia virus / Q000235:genetics
D004268:DNA-Binding Proteins; C497692:HCFC1 protein, human; D051863:Host Cell Factor C1; D007143:Immunoglobulin Heavy Chains; D046911:Macromolecular Substances; D050811:Octamer Transcription Factor-1; C494165:POU2F1 protein, human; D011994:Recombinant Proteins; D014157:Transcription Factors; D005982:Glutathione Transferase