EP300 Interacting Inhibitor Of Differentiation 3 (EID3)

EID3 has transcriptional repressor activity against nuclear repressors SF-1 (NR5A1), GR (GCCR), and ER-alpha (ESR1). Using in vitro and in vivo studies, they showed that EID3 interacted with CBP (CREBBP) and inhibited CBP-dependent transcriptional activity. Chromatin immunoprecipitation assays demonstrated that EID3 blocked recruitment of CBP to the endogenous pS2 promoter.The deduced 333-amino acid protein localized to both the nucleus and cytoplasm. Northern blot analysis of 16 human tissues detected a 2.0-kb transcript exclusively in testis. SDS-PAGE analysis detected EID3 as a 39-kD band.The authors showed that EID3 transcriptional repressor activity was reversed upon treatment with HDAC inhibitor trichostatin A. EID3 interacted with itself and EID2 to form EID3 homodimers and EID3-EID2 heterodimer complexes.