FBXO11-mediated proteolysis of BAHD1 relieves PRC2-dependent transcriptional repression in erythropoiesis

Abstract

The histone mark H3K27me3 and its reader/writer Polycomb repressive complex 2 (PRC2) mediate widespread transcriptional repression in stem and progenitor cells. Mechanisms that regulate this activity are critical for hematopoietic development but poorly understood. Here we show that the E3 ubiquitin ligase FBXO11 relieves PRC2-mediated repression during erythroid maturation by targeting its newly identified substrate BAHD1, an H3K27me3 reader that recruits transcriptional co-repressors. Erythroblasts lacking FBXO11 are developmentally delayed, with reduced expression of maturation-associated genes, most of which harbor bivalent histone marks (activating H3K4me3 and repressive H3K27me3), bind BAHD1, and fail to recruit the erythroid transcription factor GATA1. The BAHD1 complex interacts physically with PRC2 and depletion of either component restores FBXO11-deficient erythroid gene expression. Our studies identify BAHD1 as a novel effector of PRC2-mediated repression and reveal how a single E3 ubiquitin ligase eliminates PRC2 repression at developmentally poised bivalent genes during erythropoiesis.