Histone modification activities of JDP2 associated with retinoic acid-induced differentiation of F9 cells

Transcription factor JDP2 served as a repressor of AP-1 and inhibited the transactivation of the c-jun gene by p300/ATF-2, by recruitment of histone deacetylase complex (HDAC3), thereby repressing the RA-induced transcription of the c-jun gene and then inhibiting the RA-mediated differentiation of F9 cells. These results suggest that HDAC3/JDP2 and p300/ATF-2 complex play a critical role in controlling the differentiation of F9 cells, in response to RA. We also found that JDP2 has the activities associated with histone binding and inhibition of histone acetyltransferase (INHAT) as well as regulation of chromatin assembly. The region that includes that includes the amino-terminal 35 amino acids adjacent to the basic region are required for histone-binding activity and the region that includes both histone-binding domain and basic region is essential for the inhibition of INHAT. Moreover, assays of nucleosome assembly in vitro demonstrated that JDP2 also has histone chaperon activity. These results revealed that JDP2 is not only a sequence specific DNA-binding protein and but also controls the transcription of AP-1 response genes by direct regulation of histone modification.