Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 16 de 16
Filtrar
1.
Cell ; 186(5): 940-956.e20, 2023 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-36764291

RESUMO

Fingerprints are complex and individually unique patterns in the skin. Established prenatally, the molecular and cellular mechanisms that guide fingerprint ridge formation and their intricate arrangements are unknown. Here we show that fingerprint ridges are epithelial structures that undergo a truncated hair follicle developmental program and fail to recruit a mesenchymal condensate. Their spatial pattern is established by a Turing reaction-diffusion system, based on signaling between EDAR, WNT, and antagonistic BMP pathways. These signals resolve epithelial growth into bands of focalized proliferation under a precociously differentiated suprabasal layer. Ridge formation occurs as a set of waves spreading from variable initiation sites defined by the local signaling environments and anatomical intricacies of the digit, with the propagation and meeting of these waves determining the type of pattern that forms. Relying on a dynamic patterning system triggered at spatially distinct sites generates the characteristic types and unending variation of human fingerprint patterns.


Assuntos
Transdução de Sinais , Pele , Humanos , Pele/metabolismo
2.
EMBO J ; 37(21)2018 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-30275266

RESUMO

Self-renewal of embryonic stem cells (ESCs) cultured in LIF/fetal calf serum (FCS) is incomplete with some cells initiating differentiation. While this is reflected in heterogeneous expression of naive pluripotency transcription factors (TFs), the link between TF heterogeneity and differentiation is not fully understood. Here, we purify ESCs with distinct TF expression levels from LIF/FCS cultures to uncover early events during commitment from naïve pluripotency. ESCs carrying fluorescent Nanog and Esrrb reporters show Esrrb downregulation only in Nanoglow cells. Independent Esrrb reporter lines demonstrate that Esrrbnegative ESCs cannot effectively self-renew. Upon Esrrb loss, pre-implantation pluripotency gene expression collapses. ChIP-Seq identifies different regulatory element classes that bind both OCT4 and NANOG in Esrrbpositive cells. Class I elements lose NANOG and OCT4 binding in Esrrbnegative ESCs and associate with genes expressed preferentially in naïve ESCs. In contrast, Class II elements retain OCT4 but not NANOG binding in ESRRB-negative cells and associate with more broadly expressed genes. Therefore, mechanistic differences in TF function act cumulatively to restrict potency during exit from naïve pluripotency.


Assuntos
Diferenciação Celular , Regulação para Baixo , Células-Tronco Embrionárias Murinas/metabolismo , Proteína Homeobox Nanog/metabolismo , Fator 3 de Transcrição de Octâmero/metabolismo , Receptores de Estrogênio/metabolismo , Animais , Linhagem Celular , Camundongos , Células-Tronco Embrionárias Murinas/citologia , Proteína Homeobox Nanog/genética , Fator 3 de Transcrição de Octâmero/genética , Receptores de Estrogênio/genética
3.
Mol Cell ; 44(3): 361-72, 2011 Nov 04.
Artigo em Inglês | MEDLINE | ID: mdl-22055183

RESUMO

The maintenance of H3K9 and DNA methylation at imprinting control regions (ICRs) during early embryogenesis is key to the regulation of imprinted genes. Here, we reveal that ZFP57, its cofactor KAP1, and associated effectors bind selectively to the H3K9me3-bearing, DNA-methylated allele of ICRs in ES cells. KAP1 deletion induces a loss of heterochromatin marks at ICRs, whereas deleting ZFP57 or DNMTs leads to ICR DNA demethylation. Accordingly, we find that ZFP57 and KAP1 associated with DNMTs and hemimethylated DNA-binding NP95. Finally, we identify the methylated TGCCGC hexanucleotide as the motif that is recognized by ZFP57 in all ICRs and in several tens of additional loci, several of which are at least ZFP57-dependently methylated in ES cells. These results significantly advance our understanding of imprinting and suggest a general mechanism for the protection of specific loci against the wave of DNA demethylation that affects the mammalian genome during early embryogenesis.


Assuntos
Montagem e Desmontagem da Cromatina , Metilação de DNA , Células-Tronco Embrionárias/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Impressão Genômica , Proteínas Nucleares/metabolismo , Motivos de Nucleotídeos , Proteínas Repressoras/metabolismo , Animais , Sequência de Bases , Sítios de Ligação , Proteínas Estimuladoras de Ligação a CCAAT , Linhagem Celular , Proteínas Cromossômicas não Histona/metabolismo , Metilases de Modificação do DNA/metabolismo , Técnicas de Inativação de Genes , Histona-Lisina N-Metiltransferase , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Proteínas Nucleares/genética , Proteínas Metiltransferases/metabolismo , Proteínas Repressoras/genética , Proteína 28 com Motivo Tripartido , Ubiquitina-Proteína Ligases
4.
Genome Res ; 23(3): 452-61, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23233547

RESUMO

TRIM28 is critical for the silencing of endogenous retroviruses (ERVs) in embryonic stem (ES) cells. Here, we reveal that an essential impact of this process is the protection of cellular gene expression in early embryos from perturbation by cis-acting activators contained within these retroelements. In TRIM28-depleted ES cells, repressive chromatin marks at ERVs are replaced by histone modifications typical of active enhancers, stimulating transcription of nearby cellular genes, notably those harboring bivalent promoters. Correspondingly, ERV-derived sequences can repress or enhance expression from an adjacent promoter in transgenic embryos depending on their TRIM28 sensitivity in ES cells. TRIM28-mediated control of ERVs is therefore crucial not just to prevent retrotransposition, but more broadly to safeguard the transcriptional dynamics of early embryos.


Assuntos
Células-Tronco Embrionárias/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Repressoras/metabolismo , Retroelementos , Transcrição Gênica , Animais , Cromatina/genética , Cromatina/metabolismo , Mapeamento Cromossômico , Metilação de DNA , Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/virologia , Retrovirus Endógenos/genética , Deleção de Genes , Regulação da Expressão Gênica no Desenvolvimento , Inativação Gênica , Loci Gênicos , Histonas/genética , Histonas/metabolismo , Camundongos , Proteínas Nucleares/genética , Regiões Promotoras Genéticas , Proteínas Repressoras/genética , Análise de Sequência de RNA , Proteína 28 com Motivo Tripartido , Regulação para Cima
5.
Blood ; 119(20): 4675-85, 2012 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-22452978

RESUMO

Chromatin remodeling is fundamental for B-cell differentiation. In the present study, we explored the role of KAP1, the cofactor of KRAB-ZFP transcriptional repressors, in this process. B-lymphoid-specific Kap1-KO mice displayed reduced numbers of mature B cells, lower steady-state levels of Abs, and accelerated rates of decay of neutralizing Abs after viral immunization. Transcriptome analyses of Kap1-deleted B splenocytes revealed an up-regulation of PTEN, the enzymatic counteractor of PIK3 signaling, and of genes encoding DNA-damage response factors, cell-cycle regulators, and chemokine receptors. ChIP/seq studies established that KAP1 bound at or close to several of these genes and controlled chromatin status at their promoters. Genome wide, KAP1 binding sites lacked active B cell-specific enhancers and were enriched in repressive histone marks, further supporting a role for this molecule in gene silencing in vivo. Likely responsible for tethering KAP1 to at least some of these targets, a discrete subset of KRAB-ZFPs is enriched in B lymphocytes. Our results therefore reveal the role of KRAB/KAP1-mediated epigenetic regulation in B-cell development and homeostasis.


Assuntos
Linfócitos B/fisiologia , Diferenciação Celular/genética , Linfócitos/fisiologia , Proteínas Nucleares/fisiologia , Proteínas Repressoras/fisiologia , Animais , Formação de Anticorpos/genética , Formação de Anticorpos/imunologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , Proteínas de Bactérias/genética , Diferenciação Celular/imunologia , Diferenciação Celular/fisiologia , Cromatina/metabolismo , Epigênese Genética/genética , Epigênese Genética/imunologia , Epigênese Genética/fisiologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Redes Reguladoras de Genes/genética , Redes Reguladoras de Genes/fisiologia , Proteínas Luminescentes/genética , Contagem de Linfócitos , Linfócitos/imunologia , Linfócitos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Análise em Microsséries , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Proteína 28 com Motivo Tripartido
6.
Neuron ; 112(16): 2732-2748.e8, 2024 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-38897208

RESUMO

Microglia are brain-resident macrophages that contribute to central nervous system (CNS) development, maturation, and preservation. Here, we examine the consequences of permanent microglial deficiencies on brain aging using the Csf1rΔFIRE/ΔFIRE mouse model. In juvenile Csf1rΔFIRE/ΔFIRE mice, we show that microglia are dispensable for the transcriptomic maturation of other brain cell types. By contrast, with advancing age, pathologies accumulate in Csf1rΔFIRE/ΔFIRE brains, macroglia become increasingly dysregulated, and white matter integrity declines, mimicking many pathological features of human CSF1R-related leukoencephalopathy. The thalamus is particularly vulnerable to neuropathological changes in the absence of microglia, with atrophy, neuron loss, vascular alterations, macroglial dysregulation, and severe tissue calcification. We show that populating Csf1rΔFIRE/ΔFIRE brains with wild-type microglia protects against many of these pathological changes. Together with the accompanying study by Chadarevian and colleagues1, our results indicate that the lifelong absence of microglia results in an age-related neurodegenerative condition that can be counteracted via transplantation of healthy microglia.


Assuntos
Envelhecimento , Encéfalo , Microglia , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos , Microglia/patologia , Microglia/metabolismo , Animais , Camundongos , Envelhecimento/patologia , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/metabolismo , Receptores de Fator Estimulador das Colônias de Granulócitos e Macrófagos/genética , Encéfalo/patologia , Camundongos Endogâmicos C57BL , Masculino , Substância Branca/patologia , Leucoencefalopatias/patologia , Tálamo/patologia
7.
FASEB J ; 26(11): 4561-75, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22872677

RESUMO

Chromatin remodeling at specific genomic loci controls lymphoid differentiation. Here, we investigated the role played in this process by Kruppel-associated box (KRAB)-associated protein 1 (KAP1), the universal cofactor of KRAB-zinc finger proteins (ZFPs), a tetrapod-restricted family of transcriptional repressors. T-cell-specific Kap1-deleted mice displayed a significant expansion of immature thymocytes, imbalances in CD4(+)/CD8(+) cell ratios, and altered responses to TCR and TGFß stimulation when compared to littermate KAP1 control mice. Transcriptome and chromatin studies revealed that KAP1 binds T-cell-specific cis-acting regulatory elements marked by the H3K9me3 repressive mark and enriched in Ikaros/NuRD complexes. Also, KAP1 directly controls the expression of several genes involved in TCR and cytokine signaling. Among these, regulation of FoxO1 seems to play a major role in this system. Likely responsible for tethering KAP1 to at least part of its genomic targets, a small number of KRAB-ZFPs are selectively expressed in T-lymphoid cells. These results reveal the so far unsuspected yet important role of KAP1-mediated epigenetic regulation in T-lymphocyte differentiation and activation.


Assuntos
Regulação da Expressão Gênica/fisiologia , Proteínas Nucleares/metabolismo , Proteínas Repressoras/metabolismo , Linfócitos T/fisiologia , Animais , Sítios de Ligação , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/fisiologia , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/fisiologia , DNA/genética , DNA/metabolismo , Epigênese Genética , Camundongos , Camundongos Knockout , Proteínas Nucleares/genética , Análise de Sequência com Séries de Oligonucleotídeos , Fenótipo , Filogenia , Ligação Proteica , RNA/genética , RNA/metabolismo , Proteínas Repressoras/genética , Linfócitos T/citologia , Transcriptoma , Proteína 28 com Motivo Tripartido
8.
Front Immunol ; 14: 1202163, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37559721

RESUMO

During development, cortical (c) and medullary (m) thymic epithelial cells (TEC) arise from the third pharyngeal pouch endoderm. Current models suggest that within the thymic primordium most TEC exist in a bipotent/common thymic epithelial progenitor cell (TEPC) state able to generate both cTEC and mTEC, at least until embryonic day 12.5 (E12.5) in the mouse. This view, however, is challenged by recent transcriptomics and genetic evidence. We therefore set out to investigate the fate and potency of TEC in the early thymus. Here using single cell (sc) RNAseq we identify a candidate mTEC progenitor population at E12.5, consistent with recent reports. Via lineage-tracing we demonstrate this population as mTEC fate-restricted, validating our bioinformatics prediction. Using potency analyses we also establish that most E11.5 and E12.5 progenitor TEC are cTEC-fated. Finally we show that overnight culture causes most if not all E12.5 cTEC-fated TEPC to acquire functional bipotency, and provide a likely molecular mechanism for this changed differentiation potential. Collectively, our data overturn the widely held view that a common TEPC predominates in the E12.5 thymus, showing instead that sublineage-primed progenitors are present from the earliest stages of thymus organogenesis but that these early fetal TEPC exhibit cell-fate plasticity in response to extrinsic factors. Our data provide a significant advance in the understanding of fetal thymic epithelial development and thus have implications for thymus-related clinical research, in particular research focussed on generating TEC from pluripotent stem cells.


Assuntos
Células Epiteliais , Timo , Camundongos , Animais , Diferenciação Celular , Organogênese , Células-Tronco Embrionárias
9.
Mol Ther ; 17(11): 1929-37, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19707188

RESUMO

Insertional mutagenesis by long terminal repeat (LTR) enhancers in gamma-retrovirus-based vectors (GVs) in clinical trials has prompted deeper investigations into vector genotoxicity. Experimentally, self-inactivating (SIN) lentivirus vectors (LVs) and GV containing internal promoters/enhancers show reduced genotoxicity, although strong ubiquitously-active enhancers dysregulate genes independent of vector type/design. Herein, we explored the genotoxicity of beta-globin (BG) locus control region (LCR), a strong long-range lineage-specific-enhancer, with/without insulator (Ins) elements in LV using primary hematopoietic progenitors to generate in vitro immortalization (IVIM) assay mutants. LCR-containing LV had approximately 200-fold lower transforming potential, compared to the conventional GV. The LCR perturbed expression of few genes in a 300 kilobase (kb) proviral vicinity but no upregulation of genes associated with cancer, including an erythroid-specific transcription factor occurred. A further twofold reduction in transforming activity was observed with insulated LCR-containing LV. Our data indicate that toxicology studies of LCR-containing LV in mice will likely not yield any insertional oncogenesis with the numbers of animals that can be practically studied.


Assuntos
Vetores Genéticos/genética , Lentivirus/genética , Região de Controle de Locus Gênico/genética , Globinas beta/genética , Animais , Células da Medula Óssea/metabolismo , Células Cultivadas , Vetores Genéticos/efeitos adversos , Elementos Isolantes/genética , Camundongos , Camundongos Endogâmicos C57BL , Mutagênese Insercional , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução Genética
11.
Elife ; 62017 12 19.
Artigo em Inglês | MEDLINE | ID: mdl-29256862

RESUMO

Deletion of Sox2 from mouse embryonic stem cells (ESCs) causes trophectodermal differentiation. While this can be prevented by enforced expression of the related SOXB1 proteins, SOX1 or SOX3, the roles of SOXB1 proteins in epiblast stem cell (EpiSC) pluripotency are unknown. Here, we show that Sox2 can be deleted from EpiSCs with impunity. This is due to a shift in the balance of SoxB1 expression in EpiSCs, which have decreased Sox2 and increased Sox3 compared to ESCs. Consistent with functional redundancy, Sox3 can also be deleted from EpiSCs without eliminating self-renewal. However, deletion of both Sox2 and Sox3 prevents self-renewal. The overall SOXB1 levels in ESCs affect differentiation choices: neural differentiation of Sox2 heterozygous ESCs is compromised, while increased SOXB1 levels divert the ESC to EpiSC transition towards neural differentiation. Therefore, optimal SOXB1 levels are critical for each pluripotent state and for cell fate decisions during exit from naïve pluripotency.


Assuntos
Regulação da Expressão Gênica , Redes Reguladoras de Genes , Células-Tronco Embrionárias Murinas/fisiologia , Fatores de Transcrição SOXB1/metabolismo , Animais , Camadas Germinativas/embriologia , Camundongos
12.
Cancer Cell ; 29(6): 846-858, 2016 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-27238081

RESUMO

Androgen receptor (AR) signaling is a key driver of prostate cancer (PC). While androgen-deprivation therapy is transiently effective in advanced disease, tumors often progress to a lethal castration-resistant state (CRPC). We show that recurrent PC-driver mutations in speckle-type POZ protein (SPOP) stabilize the TRIM24 protein, which promotes proliferation under low androgen conditions. TRIM24 augments AR signaling, and AR and TRIM24 co-activated genes are significantly upregulated in CRPC. Expression of TRIM24 protein increases from primary PC to CRPC, and both TRIM24 protein levels and the AR/TRIM24 gene signature predict disease recurrence. Analyses in CRPC cells reveal that the TRIM24 bromodomain and the AR-interacting motif are essential to support proliferation. These data provide a rationale for therapeutic TRIM24 targeting in SPOP mutant and CRPC patients.


Assuntos
Proteínas de Transporte/genética , Proteínas Nucleares/genética , Neoplasias de Próstata Resistentes à Castração/genética , Neoplasias da Próstata/genética , Receptores Androgênicos/genética , Proteínas Repressoras/genética , Animais , Proteínas de Transporte/química , Proteínas de Transporte/metabolismo , Proliferação de Células , Progressão da Doença , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Transplante de Neoplasias , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Neoplasias de Próstata Resistentes à Castração/metabolismo , Neoplasias de Próstata Resistentes à Castração/patologia , Receptores Androgênicos/química , Receptores Androgênicos/metabolismo , Transdução de Sinais
13.
Elife ; 3: e03346, 2014 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-25163748

RESUMO

Adipose tissue is a key determinant of whole body metabolism and energy homeostasis. Unraveling the regulatory mechanisms underlying adipogenesis is therefore highly relevant from a biomedical perspective. Our current understanding of fat cell differentiation is centered on the transcriptional cascades driven by the C/EBP protein family and the master regulator PPARγ. To elucidate further components of the adipogenic gene regulatory network, we performed a large-scale transcription factor (TF) screen overexpressing 734 TFs in mouse pre-adipocytes and probed their effect on differentiation. We identified 22 novel pro-adipogenic TFs and characterized the top ranking TF, ZEB1, as being essential for adipogenesis both in vitro and in vivo. Moreover, its expression levels correlate with fat cell differentiation potential in humans. Genomic profiling further revealed that this TF directly targets and controls the expression of most early and late adipogenic regulators, identifying ZEB1 as a central transcriptional component of fat cell differentiation.


Assuntos
Adipogenia/genética , Redes Reguladoras de Genes/genética , Proteínas de Homeodomínio/genética , Fatores de Transcrição Kruppel-Like/genética , Células 3T3-L1 , Adipócitos/citologia , Adipócitos/metabolismo , Tecido Adiposo/citologia , Tecido Adiposo/metabolismo , Animais , Proteína beta Intensificadora de Ligação a CCAAT/genética , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Diferenciação Celular/genética , Linhagem Celular , Núcleo Celular/metabolismo , Expressão Gênica , Proteínas de Homeodomínio/metabolismo , Humanos , Fatores de Transcrição Kruppel-Like/metabolismo , Camundongos , Camundongos Endogâmicos C3H , PPAR gama/genética , PPAR gama/metabolismo , Ligação Proteica , Interferência de RNA , Transdução de Sinais/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Homeobox 1 de Ligação a E-box em Dedo de Zinco
14.
PLoS One ; 8(2): e56721, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23451074

RESUMO

Highly coordinated transcription networks orchestrate the self-renewal of pluripotent stem cell and the earliest steps of mammalian development. KRAB-containing zinc finger proteins represent the largest group of transcription factors encoded by the genomes of higher vertebrates including mice and humans. Together with their putatively universal cofactor KAP1, they have been implicated in events as diverse as the silencing of endogenous retroelements, the maintenance of imprinting and the pluripotent self-renewal of embryonic stem cells, although the genomic targets and specific functions of individual members of this gene family remain largely undefined. Here, we first generated a list of Ensembl-annotated KRAB-containing genes encoding the mouse and human genomes. We then defined the transcription levels of these genes in murine early embryonic cells. We found that the majority of KRAB-ZFP genes are expressed in mouse pluripotent stem cells and other early progenitors. However, we also identified distinctively cell- or stage-specific patterns of expression, some of which are pluripotency-restricted. Finally, we determined that individual KRAB-ZFP genes exhibit highly distinctive modes of expression, even when grouped in genomic clusters, and that these cannot be correlated with the presence of prototypic repressive or activating chromatin marks. These results pave the way to delineating the role of specific KRAB-ZFPs in early embryogenesis.


Assuntos
Proteínas de Transporte/metabolismo , Proteínas Nucleares/metabolismo , Células-Tronco Pluripotentes/metabolismo , Proteínas Repressoras/metabolismo , Animais , Proteínas de Transporte/genética , Células Cultivadas , Imunoprecipitação da Cromatina , Humanos , Camundongos , Proteínas Nucleares/genética , Proteínas Repressoras/genética
15.
Science ; 340(6130): 350-3, 2013 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-23493425

RESUMO

During hematopoiesis, lineage- and stage-specific transcription factors work in concert with chromatin modifiers to direct the differentiation of all blood cells. We explored the role of KRAB-containing zinc finger proteins (KRAB-ZFPs) and their cofactor KAP1 in this process. In mice, hematopoietic-restricted deletion of Kap1 resulted in severe hypoproliferative anemia. Kap1-deleted erythroblasts failed to induce mitophagy-associated genes and retained mitochondria. This was due to persistent expression of microRNAs (miRNAs) targeting mitophagy transcripts, itself secondary to a lack of repression by stage-specific KRAB-ZFPs. The KRAB/KAP1-miRNA regulatory cascade is evolutionarily conserved, as it also controls mitophagy during human erythropoiesis. Thus, a multilayered transcription regulatory system is present, in which protein- and RNA-based repressors are superimposed in combinatorial fashion to govern the timely triggering of an important differentiation event.


Assuntos
Autofagia/genética , Eritroblastos/metabolismo , Eritropoese/genética , MicroRNAs/metabolismo , Mitocôndrias/fisiologia , Proteínas Nucleares/metabolismo , Proteínas Repressoras/metabolismo , Fatores de Transcrição/metabolismo , Dedos de Zinco , Anemia/genética , Animais , Eritroblastos/ultraestrutura , Feminino , Masculino , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , MicroRNAs/genética , Mitocôndrias/genética , Proteínas Mitocondriais/metabolismo , Proteínas Nucleares/genética , Proteínas Repressoras/genética , Proteína 28 com Motivo Tripartido
16.
Mol Cancer Res ; 10(3): 401-14, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22205726

RESUMO

The repair of DNA damage in highly compact, transcriptionally silent heterochromatin requires that repair and chromatin packaging machineries be tightly coupled and regulated. KAP1 is a heterochromatin protein and co-repressor that binds to HP1 during gene silencing but is also robustly phosphorylated by Ataxia telangiectasia mutated (ATM) at serine 824 in response to DNA damage. The interplay between HP1-KAP1 binding/ATM phosphorylation during DNA repair is not known. We show that HP1α and unmodified KAP1 are enriched in endogenous heterochromatic loci and at a silent transgene prior to damage. Following damage, γH2AX and pKAP1-s824 rapidly increase and persist at these loci. Cells that lack HP1 fail to form discreet pKAP1-s824 foci after damage but levels are higher and more persistent. KAP1 is phosphorylated at serine 473 in response to DNA damage and its levels are also modulated by HP1. Unlike pKAP1-s824, pKAP1-s473 does not accumulate at damage foci but is diffusely localized in the nucleus. While HP1 association tempers KAP1 phosphorylation, this interaction also slows the resolution of γH2AX foci. Thus, HP1-dependent regulation of KAP1 influences DNA repair in heterochromatin.


Assuntos
Proteínas de Ciclo Celular/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Reparo do DNA , Proteínas de Ligação a DNA/metabolismo , Heterocromatina/metabolismo , Proteínas Nucleares/metabolismo , Fosfosserina/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Repressoras/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Sequência de Aminoácidos , Animais , Proteínas Mutadas de Ataxia Telangiectasia , Western Blotting , Fracionamento Celular , Homólogo 5 da Proteína Cromobox , Técnicas de Silenciamento de Genes , Histonas/metabolismo , Humanos , Imuno-Histoquímica , Camundongos , Modelos Biológicos , Dados de Sequência Molecular , Proteínas Mutantes/química , Proteínas Mutantes/metabolismo , Células NIH 3T3 , Proteínas Nucleares/química , Fosforilação , Proteínas Repressoras/química , Especificidade por Substrato , Transgenes/genética , Proteína 28 com Motivo Tripartido
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA