Project description:INO80 is the catalytic subunit of the multi-subunit INO80-chromatin remodeling complex that has been implicated in DNA replication, repair, and transcription regulation. Ino80-deficiency in murine spermatocytes (Ino80cKO) results in pachytene arrest of spermatocytes, due to incomplete synapsis and aberrant DNA double-strand break repair (DSBR) that leads to apoptosis. We explored the mechanism by which INO80 mediates meiotic progression. RNA-seq on Ino80cKO spermatocytes revealed major changes in transcription, indicating that an aberrant transcription program arises upon INO80 depletion. In Ino80WTspermatocytes, genome-wide analysis showed that INO80-binding sites were mostly promoter proximal and necessary for the regulation of spermatogenic gene expression, primarily of premeiotic and meiotic genes. Further, most of the genes poised for activity, as well as those genes that are active, shared INO80 binding. In Ino80cKO spermatocytes, most poised genes demonstrated de-repression due to reduced H3K27me3 enrichment, and in turn showed increased expression levels. INO80 interacts with the core PRC2 complex member SUZ12 and promotes its recruitment. Further, INO80 mediates H2A.Z incorporation at the poised promoters, which was reduced in Ino80cKO spermatocytes. Taken together, INO80 is emerging as a major regulator of the meiotic transcription program by mediating poised chromatin establishment through SUZ12 binding.
Project description:INO80 is the catalytic subunit of the multi-subunit INO80-chromatin remodeling complex that has been implicated in DNA replication, repair, and transcription regulation. Ino80-deficiency in murine spermatocytes (Ino80cKO) results in pachytene arrest of spermatocytes, due to incomplete synapsis and aberrant DNA double-strand break repair (DSBR) that leads to apoptosis. We explored the mechanism by which INO80 mediates meiotic progression. RNA-seq on Ino80cKO spermatocytes revealed major changes in transcription, indicating that an aberrant transcription program arises upon INO80 depletion. In Ino80WTspermatocytes, genome-wide analysis showed that INO80-binding sites were mostly promoter proximal and necessary for the regulation of spermatogenic gene expression, primarily of premeiotic and meiotic genes. Further, most of the genes poised for activity, as well as those genes that are active, shared INO80 binding. In Ino80cKO spermatocytes, most poised genes demonstrated de-repression due to reduced H3K27me3 enrichment, and in turn showed increased expression levels. INO80 interacts with the core PRC2 complex member SUZ12 and promotes its recruitment. Further, INO80 mediates H2A.Z incorporation at the poised promoters, which was reduced in Ino80cKO spermatocytes. Taken together, INO80 is emerging as a major regulator of the meiotic transcription program by mediating poised chromatin establishment through SUZ12 binding.
Project description:INO80 is the catalytic subunit of the multi-subunit INO80-chromatin remodeling complex that has been implicated in DNA replication, repair, and transcription regulation. Ino80-deficiency in murine spermatocytes (Ino80cKO) results in pachytene arrest of spermatocytes, due to incomplete synapsis and aberrant DNA double-strand break repair (DSBR) that leads to apoptosis. We explored the mechanism by which INO80 mediates meiotic progression. RNA-seq on Ino80cKO spermatocytes revealed major changes in transcription, indicating that an aberrant transcription program arises upon INO80 depletion. In Ino80WTspermatocytes, genome-wide analysis showed that INO80-binding sites were mostly promoter proximal and necessary for the regulation of spermatogenic gene expression, primarily of premeiotic and meiotic genes. Further, most of the genes poised for activity, as well as those genes that are active, shared INO80 binding. In Ino80cKO spermatocytes, most poised genes demonstrated de-repression due to reduced H3K27me3 enrichment, and in turn showed increased expression levels. INO80 interacts with the core PRC2 complex member SUZ12 and promotes its recruitment. Further, INO80 mediates H2A.Z incorporation at the poised promoters, which was reduced in Ino80cKO spermatocytes. Taken together, INO80 is emerging as a major regulator of the meiotic transcription program by mediating poised chromatin establishment through SUZ12 binding.
Project description:INO80 is the catalytic subunit of the multi-subunit INO80-chromatin remodeling complex that has been implicated in DNA replication, repair, and transcription regulation. Ino80-deficiency in murine spermatocytes (Ino80cKO) results in pachytene arrest of spermatocytes, due to incomplete synapsis and aberrant DNA double-strand break repair (DSBR) that leads to apoptosis. We explored the mechanism by which INO80 mediates meiotic progression. RNA-seq on Ino80cKO spermatocytes revealed major changes in transcription, indicating that an aberrant transcription program arises upon INO80 depletion. In Ino80WTspermatocytes, genome-wide analysis showed that INO80-binding sites were mostly promoter proximal and necessary for the regulation of spermatogenic gene expression, primarily of premeiotic and meiotic genes. Further, most of the genes poised for activity, as well as those genes that are active, shared INO80 binding. In Ino80cKO spermatocytes, most poised genes demonstrated de-repression due to reduced H3K27me3 enrichment, and in turn showed increased expression levels. INO80 interacts with the core PRC2 complex member SUZ12 and promotes its recruitment. Further, INO80 mediates H2A.Z incorporation at the poised promoters, which was reduced in Ino80cKO spermatocytes. Taken together, INO80 is emerging as a major regulator of the meiotic transcription program by mediating poised chromatin establishment through SUZ12 binding.
Project description:ChIP on CHIP analysis were performed to analyse the direct involvement of Ino80 in the regulation of the phosphate responsive and nucleotide metabolism genes upon phosphate starvation: We immunoprecipitated Ino80-bound chromatin fragments after formaldehyde crosslinking from cells grown in minimal medium (EMM) or minimal medium lacking phosphate and purified, amplified and probed the Ino80-associated DNA using oligonucleotide tiling arrays.
Project description:The INO80 complex is a chromatin remodeler that regulates DNA replication, repair, and transcription. Although the INO80 complex plays a crucial role in various chromatin-associated processes, the mechanism of its recruitment to specific genomic loci is not well understood. Here we used a native ChIP-MS approach to quantitatively profile modifications present on nucleosomes co-purified with INO80 from MNAse-digested HeLa chromatin.
Project description:In mammalian spermatocytes and oocytes, cohesin complexes serve several distinct functions including establishing the meiotic chromosome architecture into axes and loops, providing sister chromatid cohesion, protecting telomeres, and supporting meiotic recombination. High-resolution analysis of cohesin binding to meiotic chromosomes, however, remained to be performed, mainly because of the complexity of germ cell development and meiotic chromatin, and of the difficulty obtaining proper meiocyte populations. Here, we established a ChIP-seq approach to identify and characterize the genome-wide binding profile of cohesin specifically in murine spermatocytes. Chromatin binding of cohesin proteins SMC3, present in all cohesin complexes, and SMC1β representing the major meiotic complexes, were analyzed. Both cohesins were much reduced in coding exons as well as in 5’ and 3’ UTRs. SMC1β cohesin binding sequences coincide in a large fraction with CACA repeats and thus with transcription factor ZSCAN4C binding sites, but also with other TF sites. We observed neither overlap with recombinase DMC1 sites nor with recombination hotspot marker PRDM9 sites. Most interestingly, meiotic cohesin is strongly enriched at 5S ribosomal RNA genes. We hypothesize a role of cohesin in the regulation of meiotic rDNA stability and/or transcription.
Project description:Loss of INO80 from INO80 canonical bound regions decreases open chromatin. Loss of INO80 did not affect chromatin accessibility at autonomous sites.