biostudies-literatureMenon DUNCI NIH HHSNational Institute of General Medical SciencesNIGMS NIH HHSRP88024https://www.ebi.ac.uk/biostudies/studies/S-EPMC11594533biostudies-literatureUnknown12We present evidence implicating the BAF (BRG1/BRM Associated Factor) chromatin remodeler in meiotic sex chromosome inactivation (MSCI). By immunofluorescence (IF), the putative BAF DNA binding subunit, ARID1A (AT-rich Interaction Domain 1 a), appeared enriched on the male sex chromosomes during diplonema of meiosis I. Germ cells showing a Cre-induced loss of ARID1A arrested in pachynema and failed to repress sex-linked genes, indicating a defective MSCI. Mutant sex chromosomes displayed an abnormal presence of elongating RNA polymerase II coupled with an overall increase in chromatin accessibility detectable by ATAC-seq. We identified a role for ARID1A in promoting the preferential enrichment of the histone variant, H3.3, on the sex chromosomes, a known hallmark of MSCI. Without ARID1A, theLifeARID1A governs the silencing of sex-linked transcription during male meiosis in the mouse.PMC11594533P30 CA016086R01GM101974R01 GM101974Magnuson TChakraborty PMenon DUMurcia NfalseARID1A governs the silencing of sex-linked transcription during male meiosis in the mouse.We present evidence implicating the BAF (BRG1/BRM Associated Factor) chromatin remodeler in meiotic sex chromosome inactivation (MSCI). By immunofluorescence (IF), the putative BAF DNA binding subunit, ARID1A (AT-rich Interaction Domain 1 a), appeared enriched on the male sex chromosomes during diplonema of meiosis I. Germ cells showing a Cre-induced loss of ARID1A arrested in pachynema and failed to repress sex-linked genes, indicating a defective MSCI. Mutant sex chromosomes displayed an abnormal presence of elongating RNA polymerase II coupled with an overall increase in chromatin accessibility detectable by ATAC-seq. We identified a role for ARID1A in promoting the preferential enrichment of the histone variant, H3.3, on the sex chromosomes, a known hallmark of MSCI. Without ARID1A, th2024-01-01T00:00:00Z2024 Nov2026-06-01T13:24:05.036Z2025-04-04T22:47:50.913ZS-EPMC115945333958940010.7554/eLife.88024