The H2A.Z and NuRD associated protein HMG20A controls early head and heart developmental transcription programs

Specialized chromatin-binding proteins are required for DNA-based processes during development. We recently established PWWP2A as a direct histone variant H2A.Z interactor involved in mitosis and craniofacial development. Here, we identify the H2A.Z/PWWP2A-associated protein HMG20A as part of several chromatin-modifying complexes, including NuRD, and show that it localizes to distinct genomic regulatory regions. Hmg20a depletion causes severe head and heart developmental defects in Xenopus laevis. Our data indicate that craniofacial malformations are caused by defects in neural crest cell (NCC) migration and cartilage formation. These developmental failures are phenocopied in Hmg20a-depleted mESCs, which show inefficient differentiation into NCCs and cardiomyocytes (CM). Consequently, loss of HMG20A, which marks open promoters and enhancers, results in chromatin accessibility changes and a striking deregulation of transcription programs involved in epithelial-mesenchymal transition (EMT) and differentiation processes. Collectively, our findings implicate HMG20A as part of the H2A.Z/PWWP2A/NuRD-axis and reveal it as a key modulator of intricate developmental transcription programs that guide the differentiation of NCCs and CMs. How the histone variant H2A.Z controls cell fate remains unclear. Here, the authors reveal that the H2A.Z interacting partner HMG20A plays a key role in regulating transcription during early head and heart development.

Automated summary

In this study, the authors identified PWWP2A as a direct interactor of histone variant H2A.Z, involved in mitosis and craniofacial development. They also found that HMG20A, which associates with H2A.Z and PWWP2A, is part of chromatin-modifying complexes and localizes to specific genomic regions. Depletion of HMG20A leads to severe developmental defects, including impaired neural crest cell migration and cartilage formation.