EP300 Interacting Inhibitor Of Differentiation 1 (EID1)

Sequence analysis predicted that the 187-amino acid protein contains 2 acid patches and a C-terminal RB1-binding motif (LXCXE). Northern blot analysis detected ubiquitous expression of CRI1, with strongest expression in heart, skeletal muscle, and brain. Binding analysis showed that the acid patches and C terminus of CRI1 interacted with RB1 in transfected cells. Overexpression of CRI1 in a skeletal muscle cell line inhibited cell differentiation without reversing the expression of myogenic phenotype markers. Luciferase reporter analysis showed that CRI1 expression inhibits MYOD-dependent transcription through multiple domains and its interaction with EP300 and CREBBP, but CRI1 expression does not affect cell cycle reentry.