Heterozygous Mutations in SMARCA2 Reprogram the Enhancer Landscape by Global Retargeting of SMARCA4

Molecular Cell
Fangjian GaoDiana C Hargreaves

Abstract

Mammalian SWI/SNF complexes are multi-subunit chromatin remodeling complexes associated with an ATPase (either SMARCA4 or SMARCA2). Heterozygous mutations in the SMARCA2 ATPase cause Nicolaides-Baraitser syndrome (NCBRS), an intellectual disability syndrome associated with delayed speech onset. We engineered human embryonic stem cells (hESCs) to carry NCBRS-associated heterozygous SMARCA2 K755R or R1159Q mutations. While SMARCA2 mutant hESCs were phenotypically normal, differentiation to neural progenitors cells (NPCs) was severely impaired. We find that SMARCA2 mutations cause enhancer reorganization with loss of SOX3-dependent neural enhancers and prominent emergence of astrocyte-specific de novo enhancers. Changes in chromatin accessibility at enhancers were associated with an increase in SMARCA2 binding and retargeting of SMARCA4. We show that the AP-1 family member FRA2 is aberrantly overexpressed in SMARCA2 mutant NPCs, where it functions as a pioneer factor at de novo enhancers. Together, our results demonstrate that SMARCA2 mutations cause impaired differentiation through enhancer reprogramming via inappropriate targeting of SMARCA4.

Citations

Apr 22, 2020·Proceedings of the National Academy of Sciences of the United States of America·Wendy WenderskiJoseph G Gleeson
Dec 3, 2020·Cellular and Molecular Life Sciences : CMLS·Britt MossinkNael Nadif Kasri
Jan 14, 2020·Trends in Immunology·Jovylyn GatchalianDiana C Hargreaves
Aug 10, 2021·GeroScience·Gerald S ShadelStefania Zambetti

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