Obox4 regulates the expression of histone family genes and promotes differentiation of mouse embryonic stem cells.

Obox genes are preferentially expressed in the ovary, testis and oocyte, and play important roles in many developmental processes. In this study, we report that Obox4 and Obox6 are expressed in mouse embryonic stem cells (mESCs) and that Obox4 regulates histone family gene expression in mESCs. Obox4 protein expressing mESCs formed colonies with a flattened and irregular morphology, and exhibited decreased expression levels of self-renewal related proteins, such as Oct4 and Sox2, as well as reduced alkaline phosphatase activity. The results of microarray analysis and siRNA mediated knockdown experiments suggest that Obox4 is an upstream regulator of the histone gene family.