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The role of Xist ‐mediated Polycomb recruitment in the initiation of X‐chromosome inactivation
Author(s) -
Bousard Aurélie,
Raposo Ana Cláudia,
Żylicz Jan Jakub,
Picard Christel,
Pires Vanessa Borges,
Qi Yanyan,
Gil Cláudia,
Syx Laurène,
Chang Howard Y,
Heard Edith,
da Rocha Simão Teixeira
Publication year - 2019
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.15252/embr.201948019
Subject(s) - xist , x inactivation , biology , genetics , x chromosome , chromosome , microbiology and biotechnology , gene
Xist RNA has been established as the master regulator of X‐chromosome inactivation ( XCI ) in female eutherian mammals, but its mechanism of action remains unclear. By creating novel Xist‐ inducible mutants at the endogenous locus in male mouse embryonic stem ( ES ) cells, we dissect the role of the conserved A‐B‐C‐F repeats in the initiation of XCI . We find that transcriptional silencing can be largely uncoupled from Polycomb repressive complex 1 and complex 2 ( PRC 1/2) recruitment, which requires B and C repeats. Xist ΔB+C RNA specifically loses interaction with PCGF 3/5 subunits of PRC 1, while binding of other Xist partners is largely unaffected. However, a slight relaxation of transcriptional silencing in Xist ΔB+C indicates a role for PRC 1/2 proteins in early stabilization of gene repression. Distinct modules within the Xist RNA are therefore involved in the convergence of independent chromatin modification and gene repression pathways. In this context, Polycomb recruitment seems to be of moderate relevance in the initiation of silencing.