GSE132115
Histone H2B monoubiquitination regulates heart development via epigenetic control of cilia motility [ChIP-Seq]
Genomic analyses of patients with congenital heart disease (CHD) have identified significant contribution from mutations affecting cilia genes and chromatin remodeling genes; however, the mechanism(s) connecting chromatin remodeling to CHD are unknown. Histone H2B mono-ubiquitination (H2Bub1) is catalyzed by the RNF20 complex consisting of RNF20, RNF40 and UBE2B. Here, we show significant enrichment of loss-of-function mutations affecting H2Bub1 in CHD patients (enrichment=6.01, p=1.67x10-03), some of whom had abnormal laterality associated with cilia dysfunction. In Xenopus, knockdown of rnf20 and rnf40 results in abnormal heart looping, defective development of left-right asymmetry and impaired cilia motility. Rnf20, Rnf40 and Ube2b affect LR patterning and cilia synergistically. Examination of global H2Bub1 level in Xenopus embryos shows that H2Bub1 is developmentally regulated and requires Rnf20. To examine gene-specific H2Bub1, we performed ChIP-seq of mouse ciliated and non-ciliated tissues and showed tissue-specific H2Bub1 marks significantly enriched at cilia genes including the transcription factor Rfx3.  Rnf20 knockdown results in decreased levels of rfx3 mRNA in Xenopus, and exogenous rfx3 can rescue the Rnf20 depletion phenotype. These data suggest that Rnf20 functions at the Rfx3 locus regulating cilia motility and cardiac situs and identify H2Bub1 as an upstream transcriptional regulator controlling tissue-specific expression of cilia genes. Our findings mechanistically link the two functional gene ontologies that have been implicated in human CHD: chromatin remodeling and cilia function. Overall design: Examination of histone 2B monoubiquitination in 2 cell types in duplicate: oviduct and liver