Project description:Spermatogenesis is an essential process to generate male gametes in vertebrates, and it has become an important social health problem caused by spermatogenesis disorder. However, the molecular mechanism underlying spermatogenesis, particularly epigenetic modification in Sertoli cells of testis, remain elusive. In this study we generated Rnf20 conditional knockout mice by recombinant mothed, and only to find that Rnf20 knockout in Sertoli cells led to male infertility.
Project description:Rnf20 catalyzes lysine 120 mono-ubiquitination of histone H2B (H2Bub1) that has been previously involved in normal differentiation of embryonic stem (ES) and adult stem cells. However, the mechanisms underlying by which Rnf20 is recruited to its target chromosomal loci to generate H2Bub1 are still elusive. Here, we reveal that Fbxl19, a CxxC domain-containing protein, physically interacts with Rnf20, guides it preferentially to CpG island-containing target promoters, and thereby promotes mono-ubiqutination of H2B. We first show that up-regulation of Fbxl19 induces the level of global H2Bub1, while down-regulation of Fbxl19 reduces the level of H2Bub1 in mouse ES cells. Our genome-wide target mapping unveils the preferential occupancy of Fbxl19 on CpG island-containing promoters, and we further show that the binding of Fbxl19 is essential for the recruitment of Rnf20 to its target genes and subsequent H2Bub1. Altogether, our results demonstrate that Fbxl19 plays critical roles in the H2Bub1 pathway by recruiting Rnf20 to CGI target genes specifically and selectively.
Project description:Rnf20 catalyzes lysine 120 mono-ubiquitination of histone H2B (H2Bub1) that has been previously invloved in normal differentiation of embryonic stem (ES) and adult stem cells. However,the mechanims underlying by which Rnf20 is recruited to its target chromosomal loci to generate H2Bub1 is still elusive. Here, we reveal that Fbxl19, a CxxC domain-containing protein, physically interacts with Rnf20, guides it preferentially to CpG island-containing target promoters, and thereby promotes mono-ubiqutination of H2B. We first show that up-regulation of Fbxl19 induces the level of global H2Bub1, while down-regulation of Fbxl19 reduces the level of H2Bub1 in mouse ES cells. Our genome-wide target mapping unveils the preferential occupancy of Fbxl19 on CpG island-containing promoters, and we further show that the binding of Fbxl19 is essential for the recruitment of Rnf20 to its target genes and subsequent H2Bub1. Altogether, our results demonstrate that Fbxl19 plays critical roles in the H2Bub1 pathway by recruiting Rnf20 to CGI target genes specifically and selectively.
Project description:MLL-fusions are potent oncogenes that initiate aggressive forms of acute leukemia. As aberrant transcriptional regulators, MLL-fusion proteins alter gene expression in hematopoietic cells through interactions with the histone H3 lysine 79 (H3K79) methyltransferase DOT1L. Notably, interference with MLL-fusion cofactors like DOT1L is an emerging therapeutic strategy in this disease. Here we identify the histone H2B E3 ubiquitin ligase RNF20 as an additional requirement for MLL-fusion-mediated leukemogenesis. Suppressing the expression of Rnf20 in diverse models of MLL-rearranged leukemia leads to inhibition of cell proliferation; under tissue culture conditions as well as in vivo. Rnf20 knockdown leads to reduced expression of MLL-fusion target genes, including Hoxa9 and Meis1; effects that resemble Dot1l-inhibition. Using ChIP-seq, we found that H2B ubiquitination (H2Bub) is enriched in the body of MLL-fusion target genes, correlating with sites of H3K79 methylation and transcription elongation. Furthermore, we found that Rnf20 is required to maintain local levels of H3K79 di-methylation by Dot1l at Hoxa9 and Meis1. These findings support a model whereby co-transcriptional recruitment of Rnf20 at MLL-fusion target genes leads to amplification of Dot1l-mediated H3K79 methylation, thereby rendering leukemia cells dependent on Rnf20 to maintain their oncogenic transcriptional program. Examination of gene expression profiles upon RNF20 RNAi in MLL-AF9 acute myeloid leukemia cells
Project description:BackgroundSpermatogenesis depends on the supporting of the Sertoli cells and their communications with germ cells. However, the regulation of crosstalk between the Sertoli cells and germ cells remains unclear.ResultsIn this report, we used conditional knockout technology to generate the Sertoli cells-specific knockout of Rnf20 in mice. The Amh-Rnf20-/- male mice were infertile owing to spermatogenic failure that mimic the Sertoli cell-only syndrome (SCOS) in humans. Knockout of Rnf20 resulted in the H2BK120ub loss in the Sertoli cells and impaired the transcription elongation of the Cldn11, a gene encoding a component of tight junction. Notably, RNF20 deficiency disrupted the cell adhesion, caused disorganization of the seminiferous tubules, and led to the apoptotic cell death of both spermatogonia and spermatocytes in the seminiferous tubules.ConclusionsThis study describes a Rnf20 knockout mouse model that recapitulates the Sertoli cell-only syndrome in humans and demonstrates that RNF20 is required for male fertility through regulation of H2B ubiquitination in the Sertoli cells.
Project description:Chromatin remodeling plays very important role in cell reprogramming, but its underlying mechanism remains poorly understood. Here, we show that RNF20 is highly expressed at the early stage of reprogramming along with the accumulation of H2B ubiquitination at the same stage, and Rnf20 knockout results in the failure of reprogramming at the initial stage but not the other two stages. RNA-seq showed that Rnf20 knockout mainly affects the early stage of cell reprogramming by impairing the transcription of MET-related genes and early pluripotency genes. Importantly, Rnf20 knockout results in a more compacted chromosomes structure in reprogrammable cells, suppressing the recruitment of reprogramming transcription factors to their proper locations on the chromosomes, and finally resulting in the failure of pluripotent gene network establishment. Our results not only uncover a previously unknown function of RNF20- mediated H2B ubiquitination in cell reprogramming, but also provide mechanistic insights into the epigenetic regulation of reprogrammable cells.
Project description:Chromatin remodeling plays very important role in cell reprogramming, but its underlying mechanism remains poorly understood. Here, we show that RNF20 is highly expressed at the early stage of reprogramming along with the accumulation of H2B ubiquitination at the same stage, and Rnf20 knockout results in the failure of reprogramming at the initial stage but not the other two stages. RNA-seq showed that Rnf20 knockout mainly affects the early stage of cell reprogramming by impairing the transcription of MET-related genes and early pluripotency genes. Importantly, Rnf20 knockout results in a more compacted chromosomes structure in reprogrammable cells, suppressing the recruitment of reprogramming transcription factors to their proper locations on the chromosomes, and finally resulting in the failure of pluripotent gene network establishment. Our results not only uncover a previously unknown function of RNF20-mediated H2B ubiquitination in cell reprogramming, but also provide mechanistic insights into the epigenetic regulation of reprogrammable cells.
Project description:MLL-fusions are potent oncogenes that initiate aggressive forms of acute leukemia. As aberrant transcriptional regulators, MLL-fusion proteins alter gene expression in hematopoietic cells through interactions with the histone H3 lysine 79 (H3K79) methyltransferase DOT1L. Notably, interference with MLL-fusion cofactors like DOT1L is an emerging therapeutic strategy in this disease. Here we identify the histone H2B E3 ubiquitin ligase RNF20 as an additional requirement for MLL-fusion-mediated leukemogenesis. Suppressing the expression of Rnf20 in diverse models of MLL-rearranged leukemia leads to inhibition of cell proliferation; under tissue culture conditions as well as in vivo. Rnf20 knockdown leads to reduced expression of MLL-fusion target genes, including Hoxa9 and Meis1; effects that resemble Dot1l-inhibition. Using ChIP-seq, we found that H2B ubiquitination (H2Bub) is enriched in the body of MLL-fusion target genes, correlating with sites of H3K79 methylation and transcription elongation. Furthermore, we found that Rnf20 is required to maintain local levels of H3K79 di-methylation by Dot1l at Hoxa9 and Meis1. These findings support a model whereby co-transcriptional recruitment of Rnf20 at MLL-fusion target genes leads to amplification of Dot1l-mediated H3K79 methylation, thereby rendering leukemia cells dependent on Rnf20 to maintain their oncogenic transcriptional program.
Project description:The Mediator complex orchestrates multiple transcription factors with the Pol II apparatus for precise transcriptional control. However, its interplay with the surrounding chromatin remains poorly understood. Here, we analyze differential histone modifications between WT and MED23-/- (KO) cells and identify H2B mono-ubiquitination at lysine 120 (H2Bub) as a MED23-dependent histone modification. Using tandem affinity purification and mass spectrometry, we find that MED23 associates with the RNF20/40 complex, the enzyme for H2Bub, and show that this association is critical for the recruitment of RNF20/40 to chromatin. In a cell-free system, Mediator directly and substantially increases H2Bub on recombinant chromatin through its cooperation with RNF20/40 and the PAF complex. Integrative genome-wide analyses show that MED23 depletion specifically reduces H2Bub on a subset of MED23-contolled genes. Importantly, MED23-coupled H2Bub levels are oppositely regulated during myogenesis and lung carcinogenesis. In sum, these results establish a mechanistic link between the Mediator complex and a critical chromatin modification in coordinating transcription with cell growth and differentiation. To examine the enrichment of H2B ubiquitination, Pol II, H3K4me3, H3K79me3 in WT and KO MED23 MEF cells, we performed H2Bub ChIP-seq, Pol II ChIP-seq, H3K4me3 ChIP-seq and H3K79me3 ChIP-seq assays. 10 high-throughput sequencing data were deposited and WT, KO input data were controls for peak calling.