Modulation of Cellular Activity of a Transcription Factor CP2

초록

CP2 is an ubiquitous transcription factor that binds to and directly regulates cis elements of various target genes, including genes controlling major cellular pathways as well as genes regulated in a tissue specific manner. To understand the regulatory mechanism of cellular activity of CP2, we have screened a human fetal liver cDNA library utilizing a yeast two-hybrid approach and identified CP2-interacting clones. Six clones encoding UBC9, SUMO1, TTRAP, PIAS1, BRD7, and a p66 subunit of Mi-2 complex were confirmed their specific interactions with CP2 in both yeast and cultured mammalian cell lines. Cellular localization and transcriptional activity of CP2 are also modulated by interaction with a PIAS1 and by SUMOylation. Furthermore, similar to NF-kB or STAT1 regulation, CP2 is activated in the cytoplasm by external signals and translocates into the nucleus to activate or repress individual target genes by interacting with chromatin remodeling complexes. These studies may provide new insights into cell fate decision by CP2 during development and differentiation.