The H2Bub1-deposition complex is required for human and mouse cardiogenesis (ChIP-Seq)

De novo variants affecting monoubiquitination of histone H2B (H2Bub1) are enriched in human congenital heart disease. H2Bub1 is required in stem cell differentiation, cilia function, post-natal cardiomyocyte maturation, and transcriptional elongation. However, how H2Bub1 affects cardiogenesis is unknown. We show that the H2Bub1-deposition complex (RNF20-RNF40-UBE2B) is required for mouse cardiogenesis and for differentiation of human iPSCs into cardiomyocytes. Mice with cardiac-specific Rnf20 deletion are embryonic lethal and have abnormal myocardium. We then analyzed H2Bub1 marks during differentiation of human iPSCs into cardiomyocytes. H2Bub1 is erased from most genes at transition from cardiac mesoderm to cardiac progenitor cells, but is preserved on a subset of long cardiac-specific genes. When H2Bub1 is reduced in iPSC-cardiomyocytes, long cardiac-specific genes have fewer full-length transcripts. This correlates with H2Bub1 accumulation near the center of these genes. H2Bub1 accumulation near the center of tissue-specific genes was also observed in embryonic fibroblasts and fetal osteoblasts. In summary, we show that normal H2Bub1 distribution is required for cardiogenesis and cardiomyocyte differentiation, and point to H2Bub1 regulating tissue-specific gene expression by increasing the amount of full-length transcripts. Examination of histone 2B monoubiquitination (H2Bub1) in 5 cell types in triplicate (induced pluripotent stem cells, mesoderm, cardiac mesoderm, cardiac progenitor, and cardiomyocyte). UBE2B-/- mutants (member of the H2Bub1-deposition complex) are examined at the cardiomyocyte stage in triplicate.