New type of POU domain in germ line-specific protein Oct-4

Abstract

MEMBERS of a family of murine octamer-binding proteins inter-act specifically with the octamer motif, a transcription regulatory element found in the promoter and enhancer regions of many genes¹. Oct-4 is a maternally expressed protein that is also present in the pre-implantation mouse embryo^1,2. Although many regula-tory proteins are expressed in post-implantation embryos³, tran-scription factors regulating pre-implantation processes have remained elusive. The Oct-4 gene is therefore a prime candidate for an early developmental control gene. Here we report the complementary DNA cloning of the mouse Oct-4 gene, and the characterization of the encoded protein(s) by sequential in vitro transcription, translation, DNA-binding and protease-clipping analysis. Deletion analysis shows that the DNA-binding activity is mediated by a POU domain encoded in an open reading frame corresponding to a 324-amino-acid protein^4–13. Sequence com-parison with known POU domains reveals that Oct-4 is a novel member of the POU-family.