Project description:Polycomb repressive complex 1 (PRC1) catalyzes H2A monoubiquitination (uH2A) and regulates pluripotency in embryonic stem cells (ESCs). However the mechanisms controlling PRC1 recruitment and activity are largely unknown. Here we show that Fbxl10 interacts with Ring1B and Nspc1, forming a non-canonical PRC1. We demonstrate that Fbxl10-PRC1 is essential for H2A ubiquitination in mouse ESCs. Genome-wide analyses reveal that Fbxl10 preferentially binds to CpG islands and co-localizes with Ring1B on Polycomb target genes. Notably, Fbxl10 depletion causes modest dissociation of Ring1B but a major loss of uH2A on target genes. Furthermore rescue experiments for Fbxl10 reveal that its DNA binding capability and integration into PRC1 are required for proper H2A ubiquitination. ES cells lacking Fbxl10, like previously characterized Polycomb mutants, show a severely compromised capacity for successful differentiation. Our results shed light on a novel mechanism how CpG islands regulate chromatin function by affecting polycomb recruitment and activity. All ChIP-seq reactions were performed in either untransfected cells, cells expressing scrambled shRNA or Fbxl10 shRNA, Ring1b-/- or Suz12-/- mouse ES cells
Project description:Nearly all CpG-dense promoters are occupied by the multi-domain chromosomal protein FBXL10. We show here that complete inactivation of the Fbxl10 gene leads to dense de novo methylation only of the promoters that are co-occupied by both FBXL10 and by Polycomb Repressive Complexes; this results in pervasive defects in embryonic development and death of homozygous Fbxl10 mutant embryos at midgestation. Deletion of key components of Polycomb Repressive Complexes 1 and 2 did not lead to ectopic de novo methylation. These results indicate that FBXL10 defends Polycomb-occupied promoters against ectopic de novo methylation. FBXL10 is the first reported factor whose loss leads to a gain in genomic DNA methylation. DNA methylation analysis using RRBS and expression analysis using RNA-seq was performed on WT and Fbxl10T/T ES cells.
Project description:Nearly all CpG-dense promoters are occupied by the multi-domain chromosomal protein FBXL10. We show here that complete inactivation of the Fbxl10 gene leads to dense de novo methylation only of the promoters that are co-occupied by both FBXL10 and by Polycomb Repressive Complexes; this results in pervasive defects in embryonic development and death of homozygous Fbxl10 mutant embryos at midgestation. Deletion of key components of Polycomb Repressive Complexes 1 and 2 did not lead to ectopic de novo methylation. These results indicate that FBXL10 defends Polycomb-occupied promoters against ectopic de novo methylation. FBXL10 is the first reported factor whose loss leads to a gain in genomic DNA methylation. DNA methylation analysis using RRBS and expression analysis using RNA-seq was performed on WT and Fbxl10T/T ES cells.
Project description:Polycomb repressive complex 1 (PRC1) catalyzes H2A monoubiquitination (uH2A) and regulates pluripotency in embryonic stem cells (ESCs). However the mechanisms controlling PRC1 recruitment and activity are largely unknown. Here we show that Fbxl10 interacts with Ring1B and Nspc1, forming a non-canonical PRC1. We demonstrate that Fbxl10-PRC1 is essential for H2A ubiquitination in mouse ESCs. Genome-wide analyses reveal that Fbxl10 preferentially binds to CpG islands and co-localizes with Ring1B on Polycomb target genes. Notably, Fbxl10 depletion causes modest dissociation of Ring1B but a major loss of uH2A on target genes. Furthermore rescue experiments for Fbxl10 reveal that its DNA binding capability and integration into PRC1 are required for proper H2A ubiquitination. ES cells lacking Fbxl10, like previously characterized Polycomb mutants, show a severely compromised capacity for successful differentiation. Our results shed light on a novel mechanism how CpG islands regulate chromatin function by affecting polycomb recruitment and activity.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
Project description:Nearly all CpG-dense promoters are occupied by the multi-domain chromosomal protein FBXL10. We show here that complete inactivation of the Fbxl10 gene leads to dense de novo methylation only of the promoters that are co-occupied by both FBXL10 and by Polycomb Repressive Complexes; this results in pervasive defects in embryonic development and death of homozygous Fbxl10 mutant embryos at midgestation. Deletion of key components of Polycomb Repressive Complexes 1 and 2 did not lead to ectopic de novo methylation. These results indicate that FBXL10 defends Polycomb-occupied promoters against ectopic de novo methylation. FBXL10 is the first reported factor whose loss leads to a gain in genomic DNA methylation.
Project description:Nearly all CpG-dense promoters are occupied by the multi-domain chromosomal protein FBXL10. We show here that complete inactivation of the Fbxl10 gene leads to dense de novo methylation only of the promoters that are co-occupied by both FBXL10 and by Polycomb Repressive Complexes; this results in pervasive defects in embryonic development and death of homozygous Fbxl10 mutant embryos at midgestation. Deletion of key components of Polycomb Repressive Complexes 1 and 2 did not lead to ectopic de novo methylation. These results indicate that FBXL10 defends Polycomb-occupied promoters against ectopic de novo methylation. FBXL10 is the first reported factor whose loss leads to a gain in genomic DNA methylation.
Project description:Histones were isolated from brown adipose tissue and liver from mice housed at 28, 22, or 8 C. Quantitative top- or middle-down approaches were used to quantitate histone H4 and H3.2 proteoforms. See published article for complimentary RNA-seq and RRBS datasets.