DPPA4 modulates chromatin structure via association with DNA and core histone H3 in mouse embryonic stem cells.

Developmental pluripotency associated 4 (DPPA4) is one of the uncharacterized genes that is highly expressed in embryonic stem (ES) cells. DPPA4 is associated with active chromatin and involved in the pluripotency of mouse ES cells. However, the biological function of DPPA4 remains poorly understood. In this study, we performed fluorescence recovery after photobleaching (FRAP) analysis to examine the dynamics of DPPA4 in ES cells. FRAP analysis showed that the mobility of DPPA4 is similar to that of histone H1. In addition, biochemical analysis with purified proteins and immunoprecipitation analysis showed that DPPA4 directly binds to both DNA and core histone H3. The analysis using truncated proteins indicated that DPPA4 is associated with DNA via the N-terminal region and histone H3 via the C-terminal region. In vitro assembled chromatin showed resistance to micrococcal nuclease (MNase) digestion in the presence of DPPA4. Moreover, MNase assay and FRAP analysis with the truncated proteins implies that DPPA4 binding to both DNA and histone H3 is necessary for the chromatin structure resistant to MNase and for the proper localization of DPPA4 in ES cell nuclei. These results suggest that DPPA4 modulates the chromatin structure in association with DNA and histone H3 in ES cells.