Polycomb repressive complex 2(PRC2)contributes to catalyze the methylation of histone H3 at lysine 27 and plays vital roles in transcriptional silencing and growth development in various organisms.In Magnaporthe oryza...Polycomb repressive complex 2(PRC2)contributes to catalyze the methylation of histone H3 at lysine 27 and plays vital roles in transcriptional silencing and growth development in various organisms.In Magnaporthe oryzae,histone H3K27 is found to associate with altered transcription of in planta induced genes.However,it is still unknown whether and how H3K27me3 modification is involved in pathogenicity to rice and stress response.In this study,we found that core subunits of PRC2,Kmt6-Suz12-Eed,were required for fungal pathogenicity to rice in M.oryzae.Kmt6-Suz12-Eed localized in the nuclei and was necessary for the establishment of H3K27me3 modification.With ChIP-seq analysis,9.0%of genome regions enriched with H3K27me3 occupancy,which corresponded to 1033 genes in M.oryzae.Furthermore,deletion of Kmt6,Suz12 or Eed altered genome-wide transcriptional expression,while the de-repression genes in theΔkmt6 strain were highly associated with H3K27me3 occupancy.Notably,plenty of genes which encode effectors and secreted enzymes,secondary metabolite synthesis genes,and cell wall stress-responsive genes were directly occupied with H3K27me3 modification and de-repression in theΔkmt6 strain.These results elaborately explained how PRC2 was required for pathogenicity,which is closely related to effector modulated host immunity and host environment adaption.展开更多
Polycomb Group Proteins(PcG)are a family of epigenetic regulators responsible for the repression of an array of genes important in development and cell fate specification.PcG proteins complex to form two types of epig...Polycomb Group Proteins(PcG)are a family of epigenetic regulators responsible for the repression of an array of genes important in development and cell fate specification.PcG proteins complex to form two types of epigenetic regulators:Polycomb Repressive Complex 1 and 2(PRC1 and PRC2).Although the mechanisms regulating PRC2 recruitment and activity in mammals remain poorly understood,recent work has identified a non-canonical PRC2 in mouse embryonic stem cells(mESC)with unique activities required for repression of PRC2 target genes and necessary for mESC differentiation and somatic cell reprogramming.Here we review the functions of PRC2 in embryonic stem cells and explore the role of the newly identified mESC specific PRC2 regulatory subunits Jarid2(jumonji,AT rich interactive domain 2),Mtf2(metal response element binding transcription factor 2)and esPRC2p48.展开更多
Stem cells are unique cell populations identified in a variety of normal tissues and some cancers. Maintenance of stem cell pools is essential for normal development, tissue homeostasis, and tumorigenesis. Recent stud...Stem cells are unique cell populations identified in a variety of normal tissues and some cancers. Maintenance of stem cell pools is essential for normal development, tissue homeostasis, and tumorigenesis. Recent studies have revealed that Polycomb repressive complexes （PRCs） play a central role in maintaining stem cells by repressing cellular senescence and differentiation. Here, we will review recent findings on dynamic composition of PRC complexes and sub-complexes, how PRCs are recruited to chromatin, and their functional roles in maintaining self- renewal of stem cells. Furthermore, we will discuss how PRCs, CpG islands （CGIs）, the INK4A/ARF/INK4B locus, and developmental genes form a hierarchical regulatory axis that is utilized by a variety of stem cells to maintain their self- renewal and identities.展开更多
Polycomb group （PCG） complexes are epigenetic regulatory complexes that conduct transcriptional repression of target genes via modifying the chromatin. The two best characterized forms of PCG complexes, polycomb rep...Polycomb group （PCG） complexes are epigenetic regulatory complexes that conduct transcriptional repression of target genes via modifying the chromatin. The two best characterized forms of PCG complexes, polycomb repressive complexes 1 and 2 （PRC1 and PRC2）, are required for maintaining the sternness of embryonic stem cells and many types of adult stem cells. The spectra of target genes for PRCs are dynamically changing with cell differentiation, which is essential for proper decisions on cell fate during developmental processes, Chromobox （CBX） family proteins are canonical components in PRC1, responsible for targeting PRC1 to the chromatin. Recent studies highlight the function specifications among CBX family members in undifferentiated and differentiated stem cells, which reveal the interplay between compositional diversity and functional specificity of PRCI. In this review, we summarize the current knowledge about targeting and functional mechanisms of PRCs, emphasizing the recent breakthroughs related to CBX proteins under a number of physiological and pathological conditions.展开更多
The Polycomb group(PcG) proteins are a family of chromatin regulators and critical for the maintenance of cellular identity. The PcG machinery can be categorized into at least three multi-protein complexes, namely Pol...The Polycomb group(PcG) proteins are a family of chromatin regulators and critical for the maintenance of cellular identity. The PcG machinery can be categorized into at least three multi-protein complexes, namely Polycomb Repressive Complex 1(PRC1), PRC2, and Polycomb Repressive De UBiquitinase(PR-DUB).Their deregulation has been associated with human cancer initiation and progression. Here we review the updated understanding for Pc G proteins in transcription regulation and DNA damage repair and highlight increasing links to the hallmarks in cancer. Accordingly, we discuss some of the recent advances in drug development or strategies against cancers caused by the gain or loss of PcG functions.展开更多
The Polycomb group （PcG） genes repress gene expression mainly through chromatin modifications and regulation of chromatin structure. At present, at/east four protein complexes of PcG proteins are identified, includi...The Polycomb group （PcG） genes repress gene expression mainly through chromatin modifications and regulation of chromatin structure. At present, at/east four protein complexes of PcG proteins are identified, including Polycomb repressive complex 1 （PRC1）, Polycomb repressive complex 2 （PRC2）, PHO-repressive complex （PhoRC） and Polycomb repressive deubiquitinase （PR-DUB）. In this review, the recent discoveries of the composition of the above complexes, as well as their roles in regulating histone modifications and gene silencing are discussed. We mainly focus on the composition of PRC1 and PRC2 complex and recruitment of PcG to target genes and mechanisms of PRC1 and PRC2-mediated gene silencing. Although much progress has been made in understanding gene silencing mediated by PcG proteins, we also discuss several important questions that still remained unanswered, such as the inheritance of histone modifications during cell division.展开更多
Once thought to be transcriptional noise, large non-coding RNAs （IncRNAs） have recently been demonstrated to be functional molecules. The cell-type-specific expression patterns of lncRNAs suggest that their transcri...Once thought to be transcriptional noise, large non-coding RNAs （IncRNAs） have recently been demonstrated to be functional molecules. The cell-type-specific expression patterns of lncRNAs suggest that their transcription may be regulated epigenetically. Using a custom-designed microarray, here we examine the expression profile of IncRNAs in embryonic stem （ES） cells, lineage-restricted neuronal progenitor cells, and terminally differentiated fibroblasts. In addition, we also analyze the relationship between their expression and their promoter H3K4 and H3K27 methyla- tion patterns. We find that numerous lncRNAs in these cell types undergo changes in the levels of expression and promoter H3K4me3 and H3K27me3. Interestingly, lncRNAs that are expressed at lower levels in ES cells exhibit higher levels of H3K27me3 at their promoters. Consistent with this result, knockdown of the H3K27me3 methyltransferase Ezh2 results in derepression of these IncRNAs in ES cells. Thus, our results establish a role for Ezh2-mediated H3K27 methylation in lncRNA silencing in ES cells and reveal that lncRNAs are subject to epigenetic regulation in a similar manner to that of the protein-coding genes.展开更多
Protein O-GlcNAcylation is a monosaccharide post-translational modification maintained by two evolutionarily conserved enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Mutations in human OGT have recently be...Protein O-GlcNAcylation is a monosaccharide post-translational modification maintained by two evolutionarily conserved enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Mutations in human OGT have recently been associated with neurodevelopmental disorders, although the mechanisms linking O-GlcNAc homeostasis to neurodevelopment are not understood. Here, we investigate the effects of perturbing protein O-GlcNAcylation using transgenic Drosophila lines that overexpress a highly active OGA. We reveal that temporal reduction of protein O-GlcNAcylation in early embryos leads to reduced brain size and olfactory learning in adult Drosophila. Downregulation of O-GlcNAcylation induced by the exogenous OGA activity promotes nuclear foci formation of Polycomb-group protein Polyhomeotic and the accumulation of excess K27 trimethylation of histone H3 (H3K27me3) at the mid-blastula transition. These changes interfere with the zygotic expression of several neurodevelopmental genes, particularly short gastrulation (sog), a component of an evolutionarily conserved sog-Decapentaplegic (Dpp) signaling system required for neuroectoderm specification. Our findings highlight the importance of early embryonic O-GlcNAcylation homeostasis for the fidelity of facultative heterochromatin redeployment and initial cell fate commitment of neuronal lineages, suggesting a possible mechanism underpinning OGT-associated intellectual disability.展开更多
Objective To study the regulatory roles of SIRT1 on EZH2 expression and the further ef-fects on EZH2's repression of target gene expression. Methods The stable SIRT1 RNAi and Control RNAi HeLa cells were establish...Objective To study the regulatory roles of SIRT1 on EZH2 expression and the further ef-fects on EZH2's repression of target gene expression. Methods The stable SIRT1 RNAi and Control RNAi HeLa cells were established by in-fection with retroviruses expressing shSIRT1 and shLuc respectively followed by puromycin selection. EZH2 protein level was detected by Western blot in either whole cell lysate or the fractional cell extract. Reverse transcription-polymerase chain reaction was performed to detect the mRNA level of EZH2. Cycloheximide was used to treat SIRT1 RNAi and Control RNAi cells for protein stability assay. Chromatin immunoprecipitation (ChIP) assay was applied to measure enrichment of SIRT1, EZH2, and trimethylated H3K27 (H3K27me3) at SATB1 promoter in SIRT1 RNAi and Control RNAi cells. Results Western blot results showed that EZH2 protein level increased upon SIRT1 de-pletion. Fractional extraction results showed unchanged cytoplasmic fraction and increased chromatin fraction of EZH2 protein in SIRT1 RNAi cells. The mRNA level of EZH2 was not affected by knockdown of SIRT1. SIRT1 recruitment was not detected at the promoter region of EZH2 gene locus. The protein stability assay showed that the protein stability of EZH2 increases upon SIRT1 knockdown. Upon SIRT1 depletion, EZH2 and H3K27me3 recruitment at SATB1 promoter increases and the mRNA level of SATB1 decreases. Conclusions Depletion of SIRT1 increases the protein stability of EZH2. The regulation of EZH2 protein level by SIRT1 affects the repressive effects of EZH2 on the target gene expres-sion.展开更多
Polycomblike2(PCL2) is a well-known component of polycomb repressive complex 2(PRC2) and plays important roles in H3 K27 methylation and homeotic gene silencing.However,the involvement of PCL2 in breast cancer develop...Polycomblike2(PCL2) is a well-known component of polycomb repressive complex 2(PRC2) and plays important roles in H3 K27 methylation and homeotic gene silencing.However,the involvement of PCL2 in breast cancer development remains unclear.Here,we established PCL2 as a tumor suppressor gene in breast cancer.Expression level of PCL2 was significantly downregulated in breast cancer tissue samples observed at different TNM stages.Ectopic expression of PCL2 could significantly inhibit cell proliferation and promoted apoptosis.PCL2 also remarkably elevated levels of p53 and its targets by increasing p53 stability.Mechanistically,PCL2 protected p53 proteins from MDM2-mediated ubiquitination and degradation by sequestering MDM2 into the nucleolus.Overexpression of PCL2 also suppressed migration and invasion by inhibiting epithelial-mesenchymal transition.PCL2 expression was correlated with Ecadherin expression and was inversely correlated with vimentin expression.Furthermore,PCL2 knockdown could attenuate anti-tumor effect of MLN4924.Taken together,our findings indicated that PCL2 played a tumor suppressor role in development and progression of breast cancer and may be a prognostic and predictive marker for breast cancer.展开更多
The enhancer of zeste 2 polycomb repressive complex 2 subunit （Ezh2） is a histone-lysine N- methyltransferase enzyme that participates in DNA methylation. Ezh2 has also been reported to play crucial roles in stem ce...The enhancer of zeste 2 polycomb repressive complex 2 subunit （Ezh2） is a histone-lysine N- methyltransferase enzyme that participates in DNA methylation. Ezh2 has also been reported to play crucial roles in stem cell proliferation and differentiation. However, the detailed expression profile of Ezh2 during mouse cochlear development has not been investigated. Here, we examined the spatiotemporal expression of Ezh2 in the cochlea during embryonic and postnatal development. Ezh2 expression began to be observed in the whole otocyst nuclei at embryonic day 9.5 （E9.5）. At E12.5, Ezh2 was expressed in the nuclei of the cochlear prosensory epithelium. At E13.5 and E15.5, Ezh2 was expressed from the apical to the basal turns in the nuclei of the differentiating cochlear epithelium. At postnatal day （P） 0 and 7, the Ezh2 expression was located in the nuclei of the cochlear epithelium in all three turns and could be clearly seen in outer and inner hair cells, supporting cells, the stria vascularis, and spiral ganglion cells. Ezh2 continued to be expressed in the cochlear epithelium of adult mice. Our results provide the basic Ezh2 expression pattern and might be useful for further investigating the detailed role of Ezh2 during cochlear development.展开更多
基金the National Natural Science Foundation of China(Grant Nos.32170192 and 32000103)Zhejiang Science and Technology Major Program on Agricultural New Variety Breeding(Grant No.2021C02064)+1 种基金Key Research and Development Project of China National Rice Research Institute(Grant No.CNRRI-2020-04)the Chinese Academy of Agricultural Sciences under the‘Elite Youth’Program and the Agricultural Sciences and Technologies Innovation Program.
文摘Polycomb repressive complex 2(PRC2)contributes to catalyze the methylation of histone H3 at lysine 27 and plays vital roles in transcriptional silencing and growth development in various organisms.In Magnaporthe oryzae,histone H3K27 is found to associate with altered transcription of in planta induced genes.However,it is still unknown whether and how H3K27me3 modification is involved in pathogenicity to rice and stress response.In this study,we found that core subunits of PRC2,Kmt6-Suz12-Eed,were required for fungal pathogenicity to rice in M.oryzae.Kmt6-Suz12-Eed localized in the nuclei and was necessary for the establishment of H3K27me3 modification.With ChIP-seq analysis,9.0%of genome regions enriched with H3K27me3 occupancy,which corresponded to 1033 genes in M.oryzae.Furthermore,deletion of Kmt6,Suz12 or Eed altered genome-wide transcriptional expression,while the de-repression genes in theΔkmt6 strain were highly associated with H3K27me3 occupancy.Notably,plenty of genes which encode effectors and secreted enzymes,secondary metabolite synthesis genes,and cell wall stress-responsive genes were directly occupied with H3K27me3 modification and de-repression in theΔkmt6 strain.These results elaborately explained how PRC2 was required for pathogenicity,which is closely related to effector modulated host immunity and host environment adaption.
基金Hengbin Wang is a Sidney Kimmel Scholar and work in Wang Lab is supported by NIH Grant(GM081489).
文摘Polycomb Group Proteins(PcG)are a family of epigenetic regulators responsible for the repression of an array of genes important in development and cell fate specification.PcG proteins complex to form two types of epigenetic regulators:Polycomb Repressive Complex 1 and 2(PRC1 and PRC2).Although the mechanisms regulating PRC2 recruitment and activity in mammals remain poorly understood,recent work has identified a non-canonical PRC2 in mouse embryonic stem cells(mESC)with unique activities required for repression of PRC2 target genes and necessary for mESC differentiation and somatic cell reprogramming.Here we review the functions of PRC2 in embryonic stem cells and explore the role of the newly identified mESC specific PRC2 regulatory subunits Jarid2(jumonji,AT rich interactive domain 2),Mtf2(metal response element binding transcription factor 2)and esPRC2p48.
文摘Stem cells are unique cell populations identified in a variety of normal tissues and some cancers. Maintenance of stem cell pools is essential for normal development, tissue homeostasis, and tumorigenesis. Recent studies have revealed that Polycomb repressive complexes （PRCs） play a central role in maintaining stem cells by repressing cellular senescence and differentiation. Here, we will review recent findings on dynamic composition of PRC complexes and sub-complexes, how PRCs are recruited to chromatin, and their functional roles in maintaining self- renewal of stem cells. Furthermore, we will discuss how PRCs, CpG islands （CGIs）, the INK4A/ARF/INK4B locus, and developmental genes form a hierarchical regulatory axis that is utilized by a variety of stem cells to maintain their self- renewal and identities.
基金Project supported by the Fundamental Research Funds for the Central Universities from Lanzhou University (No.lzujbky-2014-87),China
文摘Polycomb group （PCG） complexes are epigenetic regulatory complexes that conduct transcriptional repression of target genes via modifying the chromatin. The two best characterized forms of PCG complexes, polycomb repressive complexes 1 and 2 （PRC1 and PRC2）, are required for maintaining the sternness of embryonic stem cells and many types of adult stem cells. The spectra of target genes for PRCs are dynamically changing with cell differentiation, which is essential for proper decisions on cell fate during developmental processes, Chromobox （CBX） family proteins are canonical components in PRC1, responsible for targeting PRC1 to the chromatin. Recent studies highlight the function specifications among CBX family members in undifferentiated and differentiated stem cells, which reveal the interplay between compositional diversity and functional specificity of PRCI. In this review, we summarize the current knowledge about targeting and functional mechanisms of PRCs, emphasizing the recent breakthroughs related to CBX proteins under a number of physiological and pathological conditions.
基金supported by the National Key Research and Development Program (2017YFA0504102)the National Natural Science Foundation of China (81772676, 31970579)+3 种基金the Natural Science Foundation of Tianjin Municipal Science and Technology Commission (18JCJQJC48200)Key Research Project of Tianjin Education Commission (2020ZD13)Open grant from the Chinese Academy of Medical Sciences (157-Zk19-02 and Z20-04)the Talent Excellence Program from Tianjin Medical University and Research Project of Tianjin Education Commission。
文摘The Polycomb group(PcG) proteins are a family of chromatin regulators and critical for the maintenance of cellular identity. The PcG machinery can be categorized into at least three multi-protein complexes, namely Polycomb Repressive Complex 1(PRC1), PRC2, and Polycomb Repressive De UBiquitinase(PR-DUB).Their deregulation has been associated with human cancer initiation and progression. Here we review the updated understanding for Pc G proteins in transcription regulation and DNA damage repair and highlight increasing links to the hallmarks in cancer. Accordingly, we discuss some of the recent advances in drug development or strategies against cancers caused by the gain or loss of PcG functions.
基金Supported by the National Key Basic Research Program of China(973 Program)(2011CB504206,2012CB518700)the National Natural Science Foundation of China(91019013,31221061,31200653 and 31370866)Program for New Century Excellent Talents in University(NCET-11-0410)
文摘The Polycomb group （PcG） genes repress gene expression mainly through chromatin modifications and regulation of chromatin structure. At present, at/east four protein complexes of PcG proteins are identified, including Polycomb repressive complex 1 （PRC1）, Polycomb repressive complex 2 （PRC2）, PHO-repressive complex （PhoRC） and Polycomb repressive deubiquitinase （PR-DUB）. In this review, the recent discoveries of the composition of the above complexes, as well as their roles in regulating histone modifications and gene silencing are discussed. We mainly focus on the composition of PRC1 and PRC2 complex and recruitment of PcG to target genes and mechanisms of PRC1 and PRC2-mediated gene silencing. Although much progress has been made in understanding gene silencing mediated by PcG proteins, we also discuss several important questions that still remained unanswered, such as the inheritance of histone modifications during cell division.
文摘Once thought to be transcriptional noise, large non-coding RNAs （IncRNAs） have recently been demonstrated to be functional molecules. The cell-type-specific expression patterns of lncRNAs suggest that their transcription may be regulated epigenetically. Using a custom-designed microarray, here we examine the expression profile of IncRNAs in embryonic stem （ES） cells, lineage-restricted neuronal progenitor cells, and terminally differentiated fibroblasts. In addition, we also analyze the relationship between their expression and their promoter H3K4 and H3K27 methyla- tion patterns. We find that numerous lncRNAs in these cell types undergo changes in the levels of expression and promoter H3K4me3 and H3K27me3. Interestingly, lncRNAs that are expressed at lower levels in ES cells exhibit higher levels of H3K27me3 at their promoters. Consistent with this result, knockdown of the H3K27me3 methyltransferase Ezh2 results in derepression of these IncRNAs in ES cells. Thus, our results establish a role for Ezh2-mediated H3K27 methylation in lncRNA silencing in ES cells and reveal that lncRNAs are subject to epigenetic regulation in a similar manner to that of the protein-coding genes.
基金This project has been supported by the National Natural Science Foundation of China(grants 91853108,92153301,31771589,and 32170821 to K.Y,32101034 to F.C)Department of Science and Technology of Hunan Province(grants 2017RS3013,2017XK2011,2018DK2015,2019SK1012,and 2021JJ10054 to K.Y,and the innovative team program 2019RS1010)+2 种基金Central South University(2018CX032 to K.Y,2019zzts046 to Y.Z,2019zzts339 to X.L,2021zzts497 to H.Y,and the innovation-driven team project 2020CX016)D.M.F.v.A.is supported by Wellcome Trust Investigator Award(110061)a Novo Nordisk Foundation Laureate award(NNF21OC0065969).
文摘Protein O-GlcNAcylation is a monosaccharide post-translational modification maintained by two evolutionarily conserved enzymes, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Mutations in human OGT have recently been associated with neurodevelopmental disorders, although the mechanisms linking O-GlcNAc homeostasis to neurodevelopment are not understood. Here, we investigate the effects of perturbing protein O-GlcNAcylation using transgenic Drosophila lines that overexpress a highly active OGA. We reveal that temporal reduction of protein O-GlcNAcylation in early embryos leads to reduced brain size and olfactory learning in adult Drosophila. Downregulation of O-GlcNAcylation induced by the exogenous OGA activity promotes nuclear foci formation of Polycomb-group protein Polyhomeotic and the accumulation of excess K27 trimethylation of histone H3 (H3K27me3) at the mid-blastula transition. These changes interfere with the zygotic expression of several neurodevelopmental genes, particularly short gastrulation (sog), a component of an evolutionarily conserved sog-Decapentaplegic (Dpp) signaling system required for neuroectoderm specification. Our findings highlight the importance of early embryonic O-GlcNAcylation homeostasis for the fidelity of facultative heterochromatin redeployment and initial cell fate commitment of neuronal lineages, suggesting a possible mechanism underpinning OGT-associated intellectual disability.
基金Supported by National Natural Science Foundation of China (30721063)National Basic Research Program of China (973 Program) (2005CB522402, 2006CB910403)+1 种基金National Laboratory of Medical Molecular Biology grant (2060204)Beijing municipal government grant (YB20081002301)
文摘Objective To study the regulatory roles of SIRT1 on EZH2 expression and the further ef-fects on EZH2's repression of target gene expression. Methods The stable SIRT1 RNAi and Control RNAi HeLa cells were established by in-fection with retroviruses expressing shSIRT1 and shLuc respectively followed by puromycin selection. EZH2 protein level was detected by Western blot in either whole cell lysate or the fractional cell extract. Reverse transcription-polymerase chain reaction was performed to detect the mRNA level of EZH2. Cycloheximide was used to treat SIRT1 RNAi and Control RNAi cells for protein stability assay. Chromatin immunoprecipitation (ChIP) assay was applied to measure enrichment of SIRT1, EZH2, and trimethylated H3K27 (H3K27me3) at SATB1 promoter in SIRT1 RNAi and Control RNAi cells. Results Western blot results showed that EZH2 protein level increased upon SIRT1 de-pletion. Fractional extraction results showed unchanged cytoplasmic fraction and increased chromatin fraction of EZH2 protein in SIRT1 RNAi cells. The mRNA level of EZH2 was not affected by knockdown of SIRT1. SIRT1 recruitment was not detected at the promoter region of EZH2 gene locus. The protein stability assay showed that the protein stability of EZH2 increases upon SIRT1 knockdown. Upon SIRT1 depletion, EZH2 and H3K27me3 recruitment at SATB1 promoter increases and the mRNA level of SATB1 decreases. Conclusions Depletion of SIRT1 increases the protein stability of EZH2. The regulation of EZH2 protein level by SIRT1 affects the repressive effects of EZH2 on the target gene expres-sion.
基金supported by the National Key R&D Program of China(2016YFE0129200)the National Natural Science Foundation of China(31571321,31171428)the Institute of the Fundamental Research Funds of Shandong University(2015JC036)
文摘Polycomblike2(PCL2) is a well-known component of polycomb repressive complex 2(PRC2) and plays important roles in H3 K27 methylation and homeotic gene silencing.However,the involvement of PCL2 in breast cancer development remains unclear.Here,we established PCL2 as a tumor suppressor gene in breast cancer.Expression level of PCL2 was significantly downregulated in breast cancer tissue samples observed at different TNM stages.Ectopic expression of PCL2 could significantly inhibit cell proliferation and promoted apoptosis.PCL2 also remarkably elevated levels of p53 and its targets by increasing p53 stability.Mechanistically,PCL2 protected p53 proteins from MDM2-mediated ubiquitination and degradation by sequestering MDM2 into the nucleolus.Overexpression of PCL2 also suppressed migration and invasion by inhibiting epithelial-mesenchymal transition.PCL2 expression was correlated with Ecadherin expression and was inversely correlated with vimentin expression.Furthermore,PCL2 knockdown could attenuate anti-tumor effect of MLN4924.Taken together,our findings indicated that PCL2 played a tumor suppressor role in development and progression of breast cancer and may be a prognostic and predictive marker for breast cancer.
基金This work was supported by grants from the National Basic Research Program of China （973 Program, No. 2015CB965000）, the National Natural Science Foundation of China （Nos. 81570911, 81470692, 81371094, 81230019, 81500790, 81570921, 31500852, and 31501194）, the Jiangsu Province Natural Science Foundation （Nos. BK20150022, BK20140620, and BK20150598）, the Fundamental Research Funds for the Central Universities （Nos. 2242014R30022 and 021414380037）, the Yingdong Huo Education Foundation, and the Open Research Funds of the State Key Laboratory of Genetic Engineering, Fudan University （No. SKLGE-1407）.
文摘The enhancer of zeste 2 polycomb repressive complex 2 subunit （Ezh2） is a histone-lysine N- methyltransferase enzyme that participates in DNA methylation. Ezh2 has also been reported to play crucial roles in stem cell proliferation and differentiation. However, the detailed expression profile of Ezh2 during mouse cochlear development has not been investigated. Here, we examined the spatiotemporal expression of Ezh2 in the cochlea during embryonic and postnatal development. Ezh2 expression began to be observed in the whole otocyst nuclei at embryonic day 9.5 （E9.5）. At E12.5, Ezh2 was expressed in the nuclei of the cochlear prosensory epithelium. At E13.5 and E15.5, Ezh2 was expressed from the apical to the basal turns in the nuclei of the differentiating cochlear epithelium. At postnatal day （P） 0 and 7, the Ezh2 expression was located in the nuclei of the cochlear epithelium in all three turns and could be clearly seen in outer and inner hair cells, supporting cells, the stria vascularis, and spiral ganglion cells. Ezh2 continued to be expressed in the cochlear epithelium of adult mice. Our results provide the basic Ezh2 expression pattern and might be useful for further investigating the detailed role of Ezh2 during cochlear development.
