Verrijzer C P, van Oosterhout J A, van der Vliet P C
Laboratory for Physiological Chemistry, University of Utrecht, The Netherlands.
Mol Cell Biol. 1992 Feb;12(2):542-51. doi: 10.1128/mcb.12.2.542-551.1992.
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.
POU结构域是一类基因调控蛋白家族中保守的DNA结合结构域。它由一个POU特异性结构域和一个POU同源结构域组成，二者通过一个可变连接区相连。Oct-1是一种在全身广泛表达的POU结构域转录因子。它作为单体与典型的八聚体序列（ATGCAAAT）结合。在此我们通过化学交联和蛋白质亲和层析表明，Oct-1 POU结构域单体在溶液中能够相互作用。这种结合既需要POU同源结构域，也需要POU特异性结构域。这种相互作用在溶液中是短暂的，并且可以通过与免疫球蛋白重链启动子中的七聚体-八聚体序列结合而稳定下来。这与协同性DNA结合到该位点相关。来自不同亚类的POU蛋白，包括Oct-1、Oct-2A、Oct-6以及一种含有Pit-1 POU结构域的嵌合Oct-1蛋白，能够协同结合到一个双结合位点并形成异源复合物。
