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1.
Nat Commun ; 12(1): 5341, 2021 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-34504070

RESUMO

Polycomb repressive complexes-1 and -2 (PRC1 and 2) silence developmental genes in a spatiotemporal manner during embryogenesis. How Polycomb group (PcG) proteins orchestrate down-regulation of target genes upon differentiation, however, remains elusive. Here, by differentiating embryonic stem cells into embryoid bodies, we reveal a crucial role for the PCGF1-containing variant PRC1 complex (PCGF1-PRC1) to mediate differentiation-associated down-regulation of a group of genes. Upon differentiation cues, transcription is down-regulated at these genes, in association with PCGF1-PRC1-mediated deposition of histone H2AK119 mono-ubiquitination (H2AK119ub1) and PRC2 recruitment. In the absence of PCGF1-PRC1, both H2AK119ub1 deposition and PRC2 recruitment are disrupted, leading to aberrant expression of target genes. PCGF1-PRC1 is, therefore, required for initiation and consolidation of PcG-mediated gene repression during differentiation.


Assuntos
Corpos Embrioides/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Histonas/genética , Células-Tronco Embrionárias Murinas/metabolismo , Complexo Repressor Polycomb 1/genética , Complexo Repressor Polycomb 2/genética , Animais , Diferenciação Celular , Embrião de Mamíferos , Corpos Embrioides/citologia , Histonas/metabolismo , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Camundongos , Camundongos Transgênicos , Células-Tronco Embrionárias Murinas/citologia , Fator de Crescimento Derivado de Plaquetas/genética , Fator de Crescimento Derivado de Plaquetas/metabolismo , Complexo Repressor Polycomb 1/metabolismo , Complexo Repressor Polycomb 2/metabolismo , Cultura Primária de Células , Fatores de Transcrição SOXC/genética , Fatores de Transcrição SOXC/metabolismo , Proteínas com Domínio T/genética , Proteínas com Domínio T/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transcrição Genética , Ubiquitinação
2.
Int J Mol Sci ; 22(15)2021 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-34360579

RESUMO

Ischemic heart disease can lead to myocardial infarction (MI), a major cause of morbidity and mortality worldwide. Multiple stem cell types have been safely transferred into failing human hearts, but the overall clinical cardiovascular benefits have been modest. Therefore, there is a dire need to understand the basic biology of stem cells to enhance therapeutic effects. Bmi1 is part of the polycomb repressive complex 1 (PRC1) that is involved in different processes including proliferation, survival and differentiation of stem cells. We isolated cortical bones stem cells (CBSCs) from bone stroma, and they express significantly high levels of Bmi1 compared to mesenchymal stem cells (MSCs) and cardiac-derived stem cells (CDCs). Using lentiviral transduction, Bmi1 was knocked down in the CBSCs to determine the effect of loss of Bmi1 on proliferation and survival potential with or without Bmi1 in CBSCs. Our data show that with the loss of Bmi1, there is a decrease in CBSC ability to proliferate and survive during stress. This loss of functionality is attributed to changes in histone modification, specifically histone 3 lysine 27 (H3K27). Without the proper epigenetic regulation, due to the loss of the polycomb protein in CBSCs, there is a significant decrease in cell cycle proteins, including Cyclin B, E2F, and WEE as well as an increase in DNA damage genes, including ataxia-telangiectasia mutated (ATM) and ATM and Rad3-related (ATR). In conclusion, in the absence of Bmi1, CBSCs lose their proliferative potential, have increased DNA damage and apoptosis, and more cell cycle arrest due to changes in epigenetic modifications. Consequently, Bmi1 plays a critical role in stem cell proliferation and survival through cell cycle regulation, specifically in the CBSCs. This regulation is associated with the histone modification and regulation of Bmi1, therefore indicating a novel mechanism of Bmi1 and the epigenetic regulation of stem cells.


Assuntos
Apoptose , Proliferação de Células , Osso Cortical/citologia , Epigênese Genética , Histonas/metabolismo , Complexo Repressor Polycomb 1/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Células-Tronco/citologia , Animais , Ciclo Celular , Diferenciação Celular , Células Cultivadas , Osso Cortical/lesões , Osso Cortical/metabolismo , Dano ao DNA , Histonas/genética , Camundongos , Camundongos Endogâmicos C57BL , Complexo Repressor Polycomb 1/genética , Proteínas Proto-Oncogênicas/genética , Transdução de Sinais , Células-Tronco/metabolismo
3.
Int J Mol Sci ; 22(14)2021 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-34299153

RESUMO

Correct timing of developmental phase transitions is critical for the survival and fitness of plants. Developmental phase transitions in plants are partially promoted by controlling relevant genes into active or repressive status. Polycomb Repressive Complex1 (PRC1) and PRC2, originally identified in Drosophila, are essential in initiating and/or maintaining genes in repressive status to mediate developmental phase transitions. Our review summarizes mechanisms in which the embryo-to-seedling transition, the juvenile-to-adult transition, and vegetative-to-reproductive transition in plants are mediated by PRC1 and PRC2, and suggests that PRC1 could act either before or after PRC2, or that they could function independently of each other. Details of the exact components of PRC1 and PRC2 in each developmental phase transitions and how they are recruited or removed will need to be addressed in the future.


Assuntos
Proteínas de Plantas/metabolismo , Plantas/embriologia , Complexo Repressor Polycomb 1/metabolismo , Complexo Repressor Polycomb 2/metabolismo , Plântula/embriologia , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Plantas/genética , Plantas/metabolismo , Complexo Repressor Polycomb 1/genética , Complexo Repressor Polycomb 2/genética , Plântula/genética , Plântula/metabolismo
4.
Int J Mol Sci ; 22(11)2021 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-34199929

RESUMO

BMI-1 is a key component of stem cells, which are essential for normal organ development and cell phenotype maintenance. BMI-1 expression is deregulated in cancer, resulting in the alteration of chromatin and gene transcription repression. The cellular signaling pathway that governs BMI-1 action in the ovarian carcinogenesis sequences is incompletely deciphered. In this study, we set out to analyze the immunohistochemical (IHC) BMI-1 expression in two different groups: endometriosis-related ovarian carcinoma (EOC) and non-endometriotic ovarian carcinoma (NEOC), aiming to identify the differences in its tissue profile. METHODS: BMI-1 IHC expression has been individually quantified in epithelial and in stromal components by using adapted scores systems. Statistical analysis was performed to analyze the relationship between BMI-1 epithelial and stromal profile in each group and between groups and its correlation with classical clinicopathological characteristics. RESULTS: BMI-1 expression in epithelial tumor cells was mostly low or negative in the EOC group, and predominantly positive in the NEOC group. Moreover, the stromal BMI-1 expression was variable in the EOC group, whereas in the NEOC group, stromal BMI-1 expression was mainly strong. We noted statistically significant differences between the epithelial and stromal BMI-1 profiles in each group and between the two ovarian carcinoma (OC) groups. CONCLUSIONS: Our study provides solid evidence for a different BMI-1 expression in EOC and NEOC, corresponding to the differences in their etiopathogeny. The reported differences in the BMI-1 expression of EOC and NEOC need to be further validated in a larger and homogenous cohort of study.


Assuntos
Endometriose/fisiopatologia , Endométrio/fisiopatologia , Células Epiteliais/patologia , Neoplasias Ovarianas/patologia , Complexo Repressor Polycomb 1/metabolismo , Células Estromais/patologia , Índice de Massa Corporal , Estudos de Casos e Controles , Células Epiteliais/metabolismo , Feminino , Humanos , Pessoa de Meia-Idade , Neoplasias Ovarianas/classificação , Neoplasias Ovarianas/metabolismo , Células Estromais/metabolismo
5.
6.
Cell Death Dis ; 12(7): 633, 2021 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-34148069

RESUMO

Colorectal cancer (CRC) stem cells are resistant to cancer therapy and are therefore responsible for tumour progression after conventional therapy fails. However, the molecular mechanisms underlying the maintenance of stemness are poorly understood. In this study, we identified PCGF1 as a crucial epigenetic regulator that sustains the stem cell-like phenotype of CRC. PCGF1 expression was increased in CRC and was significantly correlated with cancer progression and poor prognosis in CRC patients. PCGF1 knockdown inhibited CRC stem cell proliferation and CRC stem cell enrichment. Importantly, PCGF1 silencing impaired tumour growth in vivo. Mechanistically, PCGF1 bound to the promoters of CRC stem cell markers and activated their transcription by increasing the H3K4 histone trimethylation (H3K4me3) marks and decreasing the H3K27 histone trimethylation (H3K27me3) marks on their promoters by increasing expression of the H3K4me3 methyltransferase KMT2A and the H3K27me3 demethylase KDM6A. Our findings suggest that PCGF1 is a potential therapeutic target for CRC treatment.


Assuntos
Neoplasias Colorretais/enzimologia , Metilação de DNA , Epigênese Genética , Células-Tronco Neoplásicas/enzimologia , Complexo Repressor Polycomb 1/metabolismo , Animais , Proliferação de Células , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Feminino , Regulação Neoplásica da Expressão Gênica , Células HCT116 , Histona Desmetilases/genética , Histona Desmetilases/metabolismo , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Camundongos Endogâmicos BALB C , Camundongos Nus , Proteína de Leucina Linfoide-Mieloide/genética , Proteína de Leucina Linfoide-Mieloide/metabolismo , Células-Tronco Neoplásicas/patologia , Fenótipo , Complexo Repressor Polycomb 1/genética , Carga Tumoral , Microambiente Tumoral
7.
Cell Death Dis ; 12(7): 644, 2021 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-34168122

RESUMO

Dental pulp stem cells (DPSC) are capable of differentiating into vascular endothelial cells. Although the capacity of vascular endothelial growth factor (VEGF) to induce endothelial differentiation of stem cells is well established, mechanisms that maintain stemness and prevent vasculogenic differentiation remain unclear. Here, we tested the hypothesis that p53 signaling through p21 and Bmi-1 maintains stemness and inhibits vasculogenic differentiation. To address this hypothesis, we used primary human DPSC from permanent teeth and Stem cells from Human Exfoliated Deciduous (SHED) teeth as models of postnatal mesenchymal stem cells. DPSC seeded in biodegradable scaffolds and transplanted into immunodeficient mice generated mature human blood vessels invested with smooth muscle actin-positive mural cells. Knockdown of p53 was sufficient to induce vasculogenic differentiation of DPSC (without vasculogenic differentiation medium containing VEGF), as shown by increased expression of endothelial markers (VEGFR2, Tie-2, CD31, VE-cadherin), increased capillary sprouting in vitro; and increased DPSC-derived blood vessel density in vivo. Conversely, induction of p53 expression with small molecule inhibitors of the p53-MDM2 binding (MI-773, APG-115) was sufficient to inhibit VEGF-induced vasculogenic differentiation. Considering that p21 is a major downstream effector of p53, we knocked down p21 in DPSC and observed an increase in capillary sprouting that mimicked results observed when p53 was knocked down. Stabilization of ubiquitin activity was sufficient to induce p53 and p21 expression and reduce capillary sprouting. Interestingly, we observed an inverse and reciprocal correlation between p53/p21 and the expression of Bmi-1, a major regulator of stem cell self-renewal. Further, direct inhibition of Bmi-1 with PTC-209 resulted in blockade of capillary-like sprout formation. Collectively, these data demonstrate that p53/p21 functions through Bmi-1 to prevent the vasculogenic differentiation of DPSC.


Assuntos
Diferenciação Celular , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Polpa Dentária/metabolismo , Células Endoteliais/metabolismo , Células-Tronco Mesenquimais/metabolismo , Neovascularização Fisiológica , Complexo Repressor Polycomb 1/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Animais , Movimento Celular , Proliferação de Células , Inibidor de Quinase Dependente de Ciclina p21/genética , Polpa Dentária/citologia , Polpa Dentária/efeitos da radiação , Células Endoteliais/transplante , Feminino , Regulação da Expressão Gênica , Células HEK293 , Humanos , Camundongos SCID , Complexo Repressor Polycomb 1/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Transdução de Sinais , Transplante de Células-Tronco , Tecidos Suporte , Proteína Supressora de Tumor p53/genética , Ubiquitinação
8.
Nat Chem Biol ; 17(7): 784-793, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34155404

RESUMO

Polycomb repressive complex 1 (PRC1) is an essential chromatin-modifying complex that monoubiquitinates histone H2A and is involved in maintaining the repressed chromatin state. Emerging evidence suggests PRC1 activity in various cancers, rationalizing the need for small-molecule inhibitors with well-defined mechanisms of action. Here, we describe the development of compounds that directly bind to RING1B-BMI1, the heterodimeric complex constituting the E3 ligase activity of PRC1. These compounds block the association of RING1B-BMI1 with chromatin and inhibit H2A ubiquitination. Structural studies demonstrate that these inhibitors bind to RING1B by inducing the formation of a hydrophobic pocket in the RING domain. Our PRC1 inhibitor, RB-3, decreases the global level of H2A ubiquitination and induces differentiation in leukemia cell lines and primary acute myeloid leukemia (AML) samples. In summary, we demonstrate that targeting the PRC1 RING domain with small molecules is feasible, and RB-3 represents a valuable chemical tool to study PRC1 biology.


Assuntos
Complexo Repressor Polycomb 1/antagonistas & inibidores , Bibliotecas de Moléculas Pequenas/farmacologia , Diferenciação Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Células K562 , Modelos Moleculares , Estrutura Molecular , Complexo Repressor Polycomb 1/genética , Complexo Repressor Polycomb 1/metabolismo , Bibliotecas de Moléculas Pequenas/síntese química , Bibliotecas de Moléculas Pequenas/química , Ubiquitinação/efeitos dos fármacos
9.
Nat Commun ; 12(1): 3582, 2021 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-34117224

RESUMO

In mouse development, long-term silencing by CpG island DNA methylation is specifically targeted to germline genes; however, the molecular mechanisms of this specificity remain unclear. Here, we demonstrate that the transcription factor E2F6, a member of the polycomb repressive complex 1.6 (PRC1.6), is critical to target and initiate epigenetic silencing at germline genes in early embryogenesis. Genome-wide, E2F6 binds preferentially to CpG islands in embryonic cells. E2F6 cooperates with MGA to silence a subgroup of germline genes in mouse embryonic stem cells and in embryos, a function that critically depends on the E2F6 marked box domain. Inactivation of E2f6 leads to a failure to deposit CpG island DNA methylation at these genes during implantation. Furthermore, E2F6 is required to initiate epigenetic silencing in early embryonic cells but becomes dispensable for the maintenance in differentiated cells. Our findings elucidate the mechanisms of epigenetic targeting of germline genes and provide a paradigm for how transient repression signals by DNA-binding factors in early embryonic cells are translated into long-term epigenetic silencing during mouse development.


Assuntos
Ilhas de CpG/genética , Fator de Transcrição E2F6/genética , Fator de Transcrição E2F6/metabolismo , Desenvolvimento Embrionário/genética , Epigênese Genética , Células Germinativas/metabolismo , Animais , Sítios de Ligação , Sistemas CRISPR-Cas , Diferenciação Celular , Metilação de DNA , Inativação Gênica , Camundongos , Camundongos Knockout , Células-Tronco Embrionárias Murinas , Complexo Repressor Polycomb 1/metabolismo , RNA Interferente Pequeno
10.
Life Sci ; 280: 119748, 2021 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-34174322

RESUMO

BACKGROUND & AIMS: Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver. Long non-coding RNAs as master gene regulators play important roles in tumorigenesis and progression. However, the significance of lncRNAs and their regulatory mechanisms in HCC are largely unknown. Our study was to define the role of lncAY (long noncoding RNA AY927503) in HCC. METHODS: Methylated RNA immunoprecipitation qPCR combined with bioinformatics were used to identify the m6A modification of lncAY. qRT-PCR, western blotting and immunofluorescence were used to identify the expression of the lncAY/YTHDF2/BMI1/Wnt axis in HCC tissues and cell lines. Gain- and loss-of functions of lncAY and BMI1 were implemented to confirm their roles in the behaviors of HCC cells. RESULTS: Our findings suggested that m6A-modified lncAY expression relied on m6A "reader" protein YTHDF2. LncAY upregulated BMI1 expression in HCC cells and a notably positive relevance is evident between lncAY and BMI1 expression in TCGA HCC datasets. BMI1 was upregulated in HCC tissues and patients with higher BMI1 expression had a poor clinical prognosis. Besides, GSEA analysis showed remarkable enrichment of high BMI1 expression in gene sets associated with Wnt/ß-catenin signaling. Rescue results revealed that BMI1 reversed the suppressive effects of lncAY depletion in HCC cells. CONCLUSIONS: Our work suggested that lncAY might elevate BMI1 expression and further activate the Wnt/ß-catenin signaling. BMI1 reverses the suppressive effects of lncAY depletion in HCC cells. Collectively, our work uncovers a novel undefined regulatory signaling pathway, namely lncAY/BMI1/Wnt/ß-catenin axis, involved in liver cancer progression.


Assuntos
Carcinoma Hepatocelular/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas/genética , Complexo Repressor Polycomb 1/genética , RNA Longo não Codificante/genética , Via de Sinalização Wnt , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Humanos , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Complexo Repressor Polycomb 1/metabolismo , beta Catenina/metabolismo
11.
Nat Commun ; 12(1): 3974, 2021 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-34172737

RESUMO

Cancer stem cells (CSCs) play a critical role in invasive growth and metastasis of human head and neck squamous cell carcinoma (HNSCC). Although significant progress has been made in understanding the self-renewal and pro-tumorigenic potentials of CSCs, a key challenge remains on how to eliminate CSCs and halt metastasis effectively. Here we show that super-enhancers (SEs) play a critical role in the transcription of cancer stemness genes as well as pro-metastatic genes, thereby controlling their tumorigenic potential and metastasis. Mechanistically, we find that bromodomain-containing protein 4 (BRD4) recruits Mediators and NF-κB p65 to form SEs at cancer stemness genes such as TP63, MET and FOSL1, in addition to oncogenic transcripts. In vivo lineage tracing reveals that disrupting SEs by BET inhibitors potently inhibited CSC self-renewal and eliminated CSCs in addition to elimination of proliferating non-stem tumor cells in a mouse model of HNSCC. Moreover, disrupting SEs also inhibits the invasive growth and lymph node metastasis of human CSCs isolated from human HNSCC. Taken together, our results suggest that targeting SEs may serve as an effective therapy for HNSCC by eliminating CSCs.


Assuntos
Elementos Facilitadores Genéticos , Neoplasias de Cabeça e Pescoço/patologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Animais , Antineoplásicos/farmacologia , Azepinas/farmacologia , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/genética , Humanos , Metástase Linfática/tratamento farmacológico , Metástase Linfática/prevenção & controle , Subunidade 1 do Complexo Mediador/genética , Subunidade 1 do Complexo Mediador/metabolismo , Camundongos Endogâmicos C57BL , Camundongos SCID , NF-kappa B/genética , Células-Tronco Neoplásicas/patologia , Complexo Repressor Polycomb 1/antagonistas & inibidores , Complexo Repressor Polycomb 1/genética , Complexo Repressor Polycomb 1/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço/tratamento farmacológico , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Triazóis/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto
12.
PLoS Genet ; 17(6): e1009646, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34166371

RESUMO

Pericentromeric heterochromatin (PCH), the constitutive heterochromatin of pericentromeric regions, plays crucial roles in various cellular events, such as cell division and DNA replication. PCH forms chromocenters in the interphase nucleus, and chromocenters cluster at the prophase of meiosis. Chromocenter clustering has been reported to be critical for the appropriate progression of meiosis. However, the molecular mechanisms underlying chromocenter clustering remain elusive. In this study, we found that global DNA hypomethylation, 5hmC enrichment in PCH, and chromocenter clustering of Dnmt1-KO ESCs were similar to those of the female meiotic germ cells. Tet1 is essential for the deposition of 5hmC and facultative histone marks of H3K27me3 and H2AK119ub at PCH, as well as chromocenter clustering. RING1B, one of the core components of PRC1, is recruited to PCH by TET1, and PRC1 plays a critical role in chromocenter clustering. In addition, the rearrangement of the chromocenter under DNA hypomethylated condition was mediated by liquid-liquid phase separation. Thus, we demonstrated a novel role of Tet1 in chromocenter rearrangement in DNA hypomethylated cells.


Assuntos
DNA (Citosina-5-)-Metiltransferase 1/genética , Proteínas de Ligação a DNA/genética , DNA/genética , Epigênese Genética , Heterocromatina/química , Células-Tronco Embrionárias Murinas/metabolismo , Proteínas Proto-Oncogênicas/genética , 5-Metilcitosina/análogos & derivados , 5-Metilcitosina/metabolismo , Animais , Linhagem Celular , Centrômero/química , Centrômero/metabolismo , DNA/metabolismo , DNA (Citosina-5-)-Metiltransferase 1/deficiência , Metilação de DNA , Proteínas de Ligação a DNA/metabolismo , Feminino , Heterocromatina/metabolismo , Histonas/genética , Histonas/metabolismo , Meiose , Camundongos , Células-Tronco Embrionárias Murinas/citologia , Óvulo/citologia , Óvulo/metabolismo , Complexo Repressor Polycomb 1/genética , Complexo Repressor Polycomb 1/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo
13.
PLoS Genet ; 17(6): e1009626, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34181637

RESUMO

How organisms control when to transition between different stages of development is a key question in biology. In plants, epigenetic silencing by Polycomb repressive complex 1 (PRC1) and PRC2 plays a crucial role in promoting developmental transitions, including from juvenile-to-adult phases of vegetative growth. PRC1/2 are known to repress the master regulator of vegetative phase change, miR156, leading to the transition to adult growth, but how this process is regulated temporally is unknown. Here we investigate whether transcription factors in the VIVIPAROUS/ABI3-LIKE (VAL) gene family provide the temporal signal for the epigenetic repression of miR156. Exploiting a novel val1 allele, we found that VAL1 and VAL2 redundantly regulate vegetative phase change by controlling the overall level, rather than temporal dynamics, of miR156 expression. Furthermore, we discovered that VAL1 and VAL2 also act independently of miR156 to control this important developmental transition. In combination, our results highlight the complexity of temporal regulation in plants.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Regulação da Expressão Gênica no Desenvolvimento , MicroRNAs/genética , Complexo Repressor Polycomb 1/genética , Complexo Repressor Polycomb 2/genética , Proteínas Repressoras/genética , Alelos , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Epigênese Genética , Regulação da Expressão Gênica de Plantas , MicroRNAs/metabolismo , Folhas de Planta/genética , Folhas de Planta/crescimento & desenvolvimento , Folhas de Planta/metabolismo , Brotos de Planta/genética , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/metabolismo , Plantas Geneticamente Modificadas , Complexo Repressor Polycomb 1/metabolismo , Complexo Repressor Polycomb 2/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas Repressoras/metabolismo , Fatores de Tempo
14.
Nucleic Acids Res ; 49(12): 6621-6637, 2021 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-34009336

RESUMO

Chromatin-associated factors must locate, bind to, and assemble on specific chromatin regions to execute chromatin-templated functions. These dynamic processes are essential for understanding how chromatin achieves regulation, but direct quantification in living mammalian cells remains challenging. Over the last few years, live-cell single-molecule tracking (SMT) has emerged as a new way to observe trajectories of individual chromatin-associated factors in living mammalian cells, providing new perspectives on chromatin-templated activities. Here, we discuss the relative merits of live-cell SMT techniques currently in use. We provide new insights into how Polycomb group (PcG) proteins, master regulators of development and cell differentiation, decipher genetic and epigenetic information to achieve binding stability and highlight that Polycomb condensates facilitate target-search efficiency. We provide perspectives on liquid-liquid phase separation in organizing Polycomb targets. We suggest that epigenetic complexes integrate genetic and epigenetic information for target binding and localization and achieve target-search efficiency through nuclear organization.


Assuntos
Complexo Repressor Polycomb 1/metabolismo , Complexo Repressor Polycomb 2/metabolismo , Imagem Individual de Molécula , Cromatina/metabolismo , Epigênese Genética , Ligação Proteica , Proteínas Recombinantes de Fusão/metabolismo , Fatores de Transcrição/metabolismo
15.
Cell Death Dis ; 12(5): 495, 2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-33993198

RESUMO

Multiple myeloma (MM) is an aggressive malignancy characterized by terminally differentiated plasma cells accumulation in the bone marrow (BM). MM BM exhibits elevated MΦs (macrophages) numbers relative to healthy BM. Current evidence indicates that MM-MΦs (MM-associated macrophages) have pro-myeloma functions, and BM MM-MΦs numbers negatively correlate with patient survival. Here, we found that BMI1, a polycomb-group protein, modulates the pro-myeloma functions of MM-MΦs, which expressed higher BMI1 levels relative to normal MΦs. In the MM tumor microenvironment, hedgehog signaling in MΦs was activated by MM-derived sonic hedgehog, and BMI1 transcription subsequently activated by c-Myc. Relative to wild-type MM-MΦs, BMI1-KO (BMI1 knockout) MM-MΦs from BM cells of BMI1-KO mice exhibited reduced proliferation and suppressed expression of angiogenic factors. Additionally, BMI1-KO MM-MΦs lost their ability to protect MM cells from chemotherapy-induced cell death. In vivo analysis showed that relative to wild-type MM-MΦs, BMI1-KO MM-MΦs lost their pro-myeloma effects. Together, our data show that BMI1 mediates the pro-myeloma functions of MM-MΦs.


Assuntos
Medula Óssea/metabolismo , Macrófagos/metabolismo , Mieloma Múltiplo/genética , Complexo Repressor Polycomb 1/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Animais , Humanos , Camundongos , Mieloma Múltiplo/patologia
16.
Proc Natl Acad Sci U S A ; 118(11)2021 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-33836616

RESUMO

Despite advances that have improved the treatment of chronic myeloid leukemia (CML) patients in chronic phase, the mechanisms of the transition from chronic phase CML to blast crisis (BC) are not fully understood. Considering the key role of miR-15/16 loci in the pathogenesis of myeloid and lymphocytic leukemia, here we aimed to correlate the expression of miR-15a/16 and miR-15b/16 to progression of CML from chronic phase to BC. We analyzed the expression of the two miR-15/16 clusters in 17 CML patients in chronic phase and 22 patients in BC and in 11 paired chronic phase and BC CML patients. BC CMLs show a significant reduction of the expression of miR-15a/-15b/16 compared to CMLs in chronic phase. Moreover, BC CMLs showed an overexpression of miR-15/16 direct targets such as Bmi-1, ROR1, and Bcl-2 compared to CMLs in chronic phase. This study highlights the loss of both miR-15/16 clusters as a potential oncogenic driver in the transition from chronic phase to BC in CML patients.


Assuntos
Crise Blástica/patologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , MicroRNAs/genética , Adulto , Crise Blástica/genética , Progressão da Doença , Feminino , Regulação Leucêmica da Expressão Gênica , Loci Gênicos , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Masculino , Pessoa de Meia-Idade , Complexo Repressor Polycomb 1/genética , Complexo Repressor Polycomb 1/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Receptores Órfãos Semelhantes a Receptor Tirosina Quinase/genética , Receptores Órfãos Semelhantes a Receptor Tirosina Quinase/metabolismo
17.
Commun Biol ; 4(1): 370, 2021 04 14.
Artigo em Inglês | MEDLINE | ID: mdl-33854168

RESUMO

Lung cancer is the leading cause of cancer deaths. Tumor heterogeneity, which hampers development of targeted therapies, was herein deconvoluted via single cell RNA sequencing in aggressive human adenocarcinomas (carrying Kras-mutations) and comparable murine model. We identified a tumor-specific, mutant-KRAS-associated subpopulation which is conserved in both human and murine lung cancer. We previously reported a key role for the oncogene BMI-1 in adenocarcinomas. We therefore investigated the effects of in vivo PTC596 treatment, which affects BMI-1 activity, in our murine model. Post-treatment, MRI analysis showed decreased tumor size, while single cell transcriptomics concomitantly detected near complete ablation of the mutant-KRAS-associated subpopulation, signifying the presence of a pharmacologically targetable, tumor-associated subpopulation. Our findings therefore hold promise for the development of a targeted therapy for KRAS-mutant adenocarcinomas.


Assuntos
Benzimidazóis/farmacologia , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Células Epiteliais/efeitos dos fármacos , Neoplasias Pulmonares/tratamento farmacológico , Mutação , Proteínas Proto-Oncogênicas p21(ras)/genética , Pirazinas/farmacologia , Células A549 , Animais , Antineoplásicos , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Carcinoma Pulmonar de Células não Pequenas/patologia , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patologia , Camundongos Endogâmicos NOD , Camundongos SCID , Camundongos Transgênicos , Terapia de Alvo Molecular , Complexo Repressor Polycomb 1/genética , Complexo Repressor Polycomb 1/metabolismo , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , RNA-Seq , Análise de Célula Única , Carga Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
18.
Nat Genet ; 53(4): 539-550, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33821003

RESUMO

Parental epigenomes are established during gametogenesis. While they are largely reset after fertilization, broad domains of Polycomb repressive complex 2 (PRC2)-mediated formation of lysine 27-trimethylated histone H3 (H3K27me3) are inherited from oocytes in mice. How maternal H3K27me3 is established and inherited by embryos remains elusive. Here, we show that PRC1-mediated formation of lysine 119-monoubiquititinated histone H2A (H2AK119ub1) confers maternally heritable H3K27me3. Temporal profiling of H2AK119ub1 dynamics revealed that atypically broad H2AK119ub1 domains are established, along with H3K27me3, during oocyte growth. From the two-cell stage, H2AK119ub1 is progressively deposited at typical Polycomb targets and precedes H3K27me3. Reduction of H2AK119ub1 by depletion of Polycomb group ring finger 1 (PCGF1) and PCGF6-essential components of variant PRC1 (vPRC1)-leads to H3K27me3 loss at a subset of genes in oocytes. The gene-selective H3K27me3 deficiency is irreversibly inherited by embryos, causing loss of maternal H3K27me3-dependent imprinting, embryonic sublethality and placental enlargement at term. Collectively, our study unveils preceding dynamics of H2AK119ub1 over H3K27me3 at the maternal-to-zygotic transition, and identifies PCGF1/6-vPRC1 as an essential player in maternal epigenetic inheritance.


Assuntos
Embrião de Mamíferos/metabolismo , Epigênese Genética , Histonas/genética , Herança Materna , Complexo Repressor Polycomb 1/genética , Animais , Embrião de Mamíferos/citologia , Epigenoma , Feminino , Fertilização/genética , Histonas/metabolismo , Lisina/metabolismo , Masculino , Camundongos , Oócitos/citologia , Oócitos/crescimento & desenvolvimento , Oócitos/metabolismo , Complexo Repressor Polycomb 1/metabolismo , Complexo Repressor Polycomb 2/genética , Complexo Repressor Polycomb 2/metabolismo , Gravidez , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Espermatozoides/citologia , Espermatozoides/metabolismo , Ubiquitinação , Zigoto/citologia , Zigoto/crescimento & desenvolvimento , Zigoto/metabolismo
19.
Nat Commun ; 12(1): 2148, 2021 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-33846320

RESUMO

Deregulation of chromatin modifiers plays an essential role in the pathogenesis of medulloblastoma, the most common paediatric malignant brain tumour. Here, we identify a BMI1-dependent sensitivity to deregulation of inositol metabolism in a proportion of medulloblastoma. We demonstrate mTOR pathway activation and metabolic adaptation specifically in medulloblastoma of the molecular subgroup G4 characterised by a BMI1High;CHD7Low signature and show this can be counteracted by IP6 treatment. Finally, we demonstrate that IP6 synergises with cisplatin to enhance its cytotoxicity in vitro and extends survival in a pre-clinical BMI1High;CHD7Low xenograft model.


Assuntos
Adaptação Fisiológica , Neoplasias Cerebelares/genética , Epigênese Genética , Inositol/farmacologia , Meduloblastoma/genética , Adaptação Fisiológica/efeitos dos fármacos , Animais , Contagem de Células , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cisplatino/farmacologia , Proteínas de Ligação a DNA/metabolismo , Sinergismo Farmacológico , Epigênese Genética/efeitos dos fármacos , Humanos , Camundongos , Células-Tronco Neurais/metabolismo , Consumo de Oxigênio/efeitos dos fármacos , Fosfatidilinositóis/metabolismo , Complexo Repressor Polycomb 1/metabolismo , Regiões Promotoras Genéticas/genética , Proteínas Proto-Oncogênicas/metabolismo , Transdução de Sinais , Proteínas com Domínio T , Serina-Treonina Quinases TOR/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
20.
Int J Mol Sci ; 22(8)2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33916959

RESUMO

The recessive form of dystrophic epidermolysis bullosa (RDEB) is a crippling disease caused by impairments in the junctions of the dermis and the basement membrane of the epidermis. Using ectopic expression of hTERT/hTERT + BMI-1 in primary cells, we developed expansible cultures of RDEB fibroblasts and keratinocytes. We showed that they display the properties of their founders, including morphology, contraction ability and expression of the respective specific markers including reduced secretion of type VII collagen (C7). The immortalized keratinocytes retained normal stratification in 3D skin equivalents. The comparison of secreted protein patterns from immortalized RDEB and healthy keratinocytes revealed the differences in the contents of the extracellular matrix that were earlier observed specifically for RDEB. We demonstrated the possibility to reverse the genotype of immortalized cells to the state closer to the progenitors by the Cre-dependent hTERT switch off. Increased ß-galactosidase activity and reduced proliferation of fibroblasts were shown after splitting out of transgenes. We anticipate our cell lines to be tractable models for studying RDEB from the level of single-cell changes to the evaluation of 3D skin equivalents. Our approach permits the creation of standardized and expandable models of RDEB that can be compared with the models based on primary cell cultures.


Assuntos
Fibroblastos/metabolismo , Recombinação Homóloga , Integrases/metabolismo , Queratinócitos/metabolismo , Telomerase/genética , Transgenes , Adolescente , Adulto , Biomarcadores , Linhagem Celular Transformada , Proliferação de Células , Senescência Celular/genética , Criança , Epidermólise Bolhosa Distrófica/etiologia , Epidermólise Bolhosa Distrófica/metabolismo , Feminino , Fibroblastos/patologia , Imunofluorescência , Técnicas de Silenciamento de Genes , Ordem dos Genes , Vetores Genéticos/genética , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Mutação , Complexo Repressor Polycomb 1/genética , Complexo Repressor Polycomb 1/metabolismo , Cultura Primária de Células , Proteômica/métodos , Telomerase/metabolismo , Adulto Jovem
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