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1.
Cell Rep ; 30(11): 3717-3728.e6, 2020 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-32187544

RESUMO

Understanding the mechanisms of activity-dependent gene transcription underlying adaptive behaviors is challenging at neuronal-subtype resolution. Using cell-type specific molecular analysis in agouti-related peptide (AgRP) neurons, we reveal that the profound hunger-induced transcriptional changes greatly depend on plant homeodomain finger protein 6 (PHF6), a transcriptional repressor enriched in AgRP neurons. Loss of PHF6 in the satiated mice results in a hunger-state-shifting transcriptional profile, while hunger fails to further induce a rapid and robust activity-dependent gene transcription in PHF6-deficient AgRP neurons. We reveal that PHF6 binds to the promoters of a subset of immediate-early genes (IEGs) and that this chromatin binding is dynamically regulated by hunger state. Depletion of PHF6 decreases hunger-driven feeding motivation and makes the mice resistant to body weight gain under repetitive fasting-refeeding conditions. Our work identifies a neuronal subtype-specific transcriptional repressor that modulates transcriptional profiles in different nutritional states and enables adaptive eating behavior.

2.
F1000Res ; 92020.
Artigo em Inglês | MEDLINE | ID: mdl-32148779

RESUMO

Apoptotic cells are commonly observed in a broad range of tissues during mammalian embryonic and fetal development. Specific requirements and functions of programmed cell death were inferred from early observations. These inferences did not hold up to functional proof for a requirement of apoptosis for normal tissue development in all cases. In this review, we summarize how the appraisal of the importance of developmental apoptosis has changed over the years, in particular with detailed functional assessment, such as by using gene-targeted mice lacking essential initiators or mediators of apoptosis. In recent years, the essentials of developmental apoptosis have emerged. We hypothesize that apoptosis is predominantly required to balance cell proliferation. The two interdependent processes-cell proliferation and apoptosis-together more powerfully regulate tissue growth than does each process alone. We proposed that this ensures that tissues and cell populations attain the appropriate size that allows fusion in the body midline and retain the size of cavities once formed. In addition, a limited number of tissues, albeit not all previously proposed, rely on apoptosis for remodeling, chiefly aortic arch remodeling, elimination of supernumerary neurons, removal of vaginal septa, and removal of interdigital webs in the formation of hands and feet.

3.
J Med Chem ; 2020 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-32118427

RESUMO

A high-throughput screen designed to discover new inhibitors of histone acetyltransferase KAT6A uncovered CTX-0124143 (1), a unique aryl acylsulfonohydrazide with an IC50 of 1.0 µM. Using this acylsulfonohydrazide as a template, we herein disclose the results of our extensive structure-activity relationship investigations, which resulted in the discovery of advanced compounds such as 55 and 80. These two compounds represent significant improvements on our recently reported prototypical lead WM-8014 (3) as they are not only equivalently potent as inhibitors of KAT6A but are less lipophilic and significantly more stable to microsomal degradation. Furthermore, during this process, we discovered a distinct structural subclass that contains key 2-fluorobenzenesulfonyl and phenylpyridine motifs, culminating in the discovery of WM-1119 (4). This compound is a highly potent KAT6A inhibitor (IC50 = 6.3 nM; KD = 0.002 µM), competes with Ac-CoA by binding to the Ac-CoA binding site, and has an oral bioavailability of 56% in rats.

4.
Mol Cell Biol ; 40(4)2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-31767635

RESUMO

HBO1 (MYST2/KAT7) is essential for histone 3 lysine 14 acetylation (H3K14ac) but is dispensable for H4 acetylation and DNA replication in mouse tissues. In contrast, previous studies using small interfering RNA (siRNA) knockdown in human cell lines have suggested that HBO1 is essential for DNA replication. To determine if HBO1 has distinctly different roles in immortalized human cell lines and normal mouse cells, we performed siRNA knockdown of HBO1. In addition, we used CRISPR/Cas9 to generate 293T, MCF7, and HeLa cell lines lacking HBO1. Using both techniques, we show that HBO1 is essential for all H3K14ac in human cells and is unlikely to have a direct effect on H4 acetylation and only has minor effects on cell proliferation. Surprisingly, the loss of HBO1 and H3K14ac in HeLa cells led to the secondary loss of almost all H4 acetylation after 4 weeks. Thus, HBO1 is dispensable for DNA replication and cell proliferation in immortalized human cells. However, while cell proliferation proceeded without HBO1 and H3K14ac, HBO1 gene deletion led to profound changes in cell adhesion, particularly in 293T cells. Consistent with this phenotype, the loss of HBO1 in both 293T and HeLa principally affected genes mediating cell adhesion, with comparatively minor effects on other cellular processes.

5.
Nature ; 577(7789): 266-270, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31827282

RESUMO

Acute myeloid leukaemia (AML) is a heterogeneous disease characterized by transcriptional dysregulation that results in a block in differentiation and increased malignant self-renewal. Various epigenetic therapies aimed at reversing these hallmarks of AML have progressed into clinical trials, but most show only modest efficacy owing to an inability to effectively eradicate leukaemia stem cells (LSCs)1. Here, to specifically identify novel dependencies in LSCs, we screened a bespoke library of small hairpin RNAs that target chromatin regulators in a unique ex vivo mouse model of LSCs. We identify the MYST acetyltransferase HBO1 (also known as KAT7 or MYST2) and several known members of the HBO1 protein complex as critical regulators of LSC maintenance. Using CRISPR domain screening and quantitative mass spectrometry, we identified the histone acetyltransferase domain of HBO1 as being essential in the acetylation of histone H3 at K14. H3 acetylated at K14 (H3K14ac) facilitates the processivity of RNA polymerase II to maintain the high expression of key genes (including Hoxa9 and Hoxa10) that help to sustain the functional properties of LSCs. To leverage this dependency therapeutically, we developed a highly potent small-molecule inhibitor of HBO1 and demonstrate its mode of activity as a competitive analogue of acetyl-CoA. Inhibition of HBO1 phenocopied our genetic data and showed efficacy in a broad range of human cell lines and primary AML cells from patients. These biological, structural and chemical insights into a therapeutic target in AML will enable the clinical translation of these findings.

6.
Nat Commun ; 10(1): 4724, 2019 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-31624313

RESUMO

Acetylation of histone H3K23 has emerged as an essential posttranslational modification associated with cancer and learning and memory impairment, yet our understanding of this epigenetic mark remains insufficient. Here, we identify the native MORF complex as a histone H3K23-specific acetyltransferase and elucidate its mechanism of action. The acetyltransferase function of the catalytic MORF subunit is positively regulated by the DPF domain of MORF (MORFDPF). The crystal structure of MORFDPF in complex with crotonylated H3K14 peptide provides mechanistic insight into selectivity of this epigenetic reader and its ability to recognize both histone and DNA. ChIP data reveal the role of MORFDPF in MORF-dependent H3K23 acetylation of target genes. Mass spectrometry, biochemical and genomic analyses show co-existence of the H3K23ac and H3K14ac modifications in vitro and co-occupancy of the MORF complex, H3K23ac, and H3K14ac at specific loci in vivo. Our findings suggest a model in which interaction of MORFDPF with acylated H3K14 promotes acetylation of H3K23 by the native MORF complex to activate transcription.


Assuntos
Histona Acetiltransferases/metabolismo , Histonas/metabolismo , Lisina/metabolismo , Processamento de Proteína Pós-Traducional , Acetilação , Acilação , Sítios de Ligação/genética , Linhagem Celular Tumoral , Cristalografia por Raios X , Células HEK293 , Histona Acetiltransferases/química , Histona Acetiltransferases/genética , Histonas/química , Humanos , Células K562 , Simulação de Dinâmica Molecular , Ligação Proteica , Domínios Proteicos
7.
Development ; 146(14)2019 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-31340933

RESUMO

Oral clefts are common birth defects. Individuals with oral clefts who have identical genetic mutations regularly present with variable penetrance and severity. Epigenetic or chromatin-mediated mechanisms are commonly invoked to explain variable penetrance. However, specific examples of these are rare. Two functional copies of the MOZ (KAT6A, MYST3) gene, encoding a MYST family lysine acetyltransferase chromatin regulator, are essential for human craniofacial development, but the molecular role of MOZ in this context is unclear. Using genetic interaction and genomic studies, we have investigated the effects of loss of MOZ on the gene expression program during mouse development. Among the more than 500 genes differentially expressed after loss of MOZ, 19 genes had previously been associated with cleft palates. These included four distal-less homeobox (DLX) transcription factor-encoding genes, Dlx1, Dlx2, Dlx3 and Dlx5 and DLX target genes (including Barx1, Gbx2, Osr2 and Sim2). MOZ occupied the Dlx5 locus and was required for normal levels of histone H3 lysine 9 acetylation. MOZ affected Dlx gene expression cell-autonomously within neural crest cells. Our study identifies a specific program by which the chromatin modifier MOZ regulates craniofacial development.

8.
Exp Hematol ; 75: 1-10, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31175894

RESUMO

Hematopoietic stem cells (HSCs) have been studied intensely for more than half a century. As a result, the properties of HSCs have become a paradigm of adult stem cell biology and function. The "classical" view of hematopoiesis suggests that the HSCs sit at the top of a hierarchy and that differentiation involves sequential production of multipotent and lineage committed progenitors with limited self-renewal capacity. This view of hematopoiesis is certainly valid after transplantation of HSCs, where, with appropriate support, a single HSC can regenerate the entire hematopoietic system of the recipient. However, it is not clear whether HSCs perform the same function during steady-state hematopoiesis. Indeed, studies have shown that the majority of classical HSCs are not required for ongoing steady-state adult hematopoiesis. Several reports suggest that steady-state hematopoiesis relies on highly proliferative cells with more lineage restricted characteristics, a finding that was not anticipated based on results from transplantation experiments. However, other studies indicate a more substantial HSC contribution. Nevertheless, the notion of HSCs as distinct from progenitors appears to be simplistic in view of ample evidence for heterogeneity within the stem cell compartment. In this review we discuss recent results and controversies surrounding HSCs.


Assuntos
Proliferação de Células , Hematopoese , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/metabolismo , Adulto , Animais , Humanos
9.
Cell Rep ; 27(2): 442-454.e5, 2019 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-30970248

RESUMO

Neural tube defects (NTDs) are common birth defects in humans and show an unexplained female bias. Female mice lacking the tumor suppressor p53 display NTDs with incomplete penetrance. We found that the combined loss of pro-apoptotic BIM and p53 caused 100% penetrant, female-exclusive NTDs, which allowed us to investigate the female-specific functions of p53. We report that female p53-/- embryonic neural tube samples show fewer cells with inactive X chromosome markers Xist and H3K27me3 and a concomitant increase in biallelic expression of the X-linked genes, Huwe1 and Usp9x. Decreased Xist and increased X-linked gene expression was confirmed by RNA sequencing. Moreover, we found that p53 directly bound response elements in the X chromosome inactivation center (XIC). Together, these findings suggest p53 directly activates XIC genes, without which there is stochastic failure in X chromosome inactivation, and that X chromosome inactivation failure may underlie the female bias in neural tube closure defects.

10.
Blood ; 133(16): 1729-1741, 2019 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-30755422

RESUMO

Somatically acquired mutations in PHF6 (plant homeodomain finger 6) frequently occur in hematopoietic malignancies and often coincide with ectopic expression of TLX3. However, there is no functional evidence to demonstrate whether these mutations contribute to tumorigenesis. Similarly, the role of PHF6 in hematopoiesis is unknown. We report here that Phf6 deletion in mice resulted in a reduced number of hematopoietic stem cells (HSCs), an increased number of hematopoietic progenitor cells, and an increased proportion of cycling stem and progenitor cells. Loss of PHF6 caused increased and sustained hematopoietic reconstitution in serial transplantation experiments. Interferon-stimulated gene expression was upregulated in the absence of PHF6 in hematopoietic stem and progenitor cells. The numbers of hematopoietic progenitor cells and cycling hematopoietic stem and progenitor cells were restored to normal by combined loss of PHF6 and the interferon α and ß receptor subunit 1. Ectopic expression of TLX3 alone caused partially penetrant leukemia. TLX3 expression and loss of PHF6 combined caused fully penetrant early-onset leukemia. Our data suggest that PHF6 is a hematopoietic tumor suppressor and is important for fine-tuning hematopoietic stem and progenitor cell homeostasis.


Assuntos
Células-Tronco Hematopoéticas/citologia , Proteínas de Homeodomínio/metabolismo , Leucemia/etiologia , Proteínas Repressoras/fisiologia , Animais , Carcinogênese , Regulação da Expressão Gênica , Humanos , Camundongos , Camundongos Knockout , Receptores de Interferon , Proteínas Repressoras/genética , Proteínas Supressoras de Tumor
11.
Genes Dev ; 32(21-22): 1420-1429, 2018 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-30366906

RESUMO

Mutations in Trp53, prevalent in human cancer, are reported to drive tumorigenesis through dominant-negative effects (DNEs) over wild-type TRP53 function as well as neomorphic gain-of-function (GOF) activity. We show that five TRP53 mutants do not accelerate lymphomagenesis on a TRP53-deficient background but strongly synergize with c-MYC overexpression in a manner that distinguishes the hot spot Trp53 mutations. RNA sequencing revealed that the mutant TRP53 DNE does not globally repress wild-type TRP53 function but disproportionately impacts a subset of wild-type TRP53 target genes. Accordingly, TRP53 mutant proteins impair pathways for DNA repair, proliferation, and metabolism in premalignant cells. This reveals that, in our studies of lymphomagenesis, mutant TRP53 drives tumorigenesis primarily through the DNE, which modulates wild-type TRP53 function in a manner advantageous for neoplastic transformation.


Assuntos
Carcinogênese/genética , Mutação , Proteína Supressora de Tumor p53/genética , Animais , Linfoma/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteína Supressora de Tumor p53/metabolismo
12.
Cell Rep ; 24(12): 3285-3295.e4, 2018 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-30232009

RESUMO

Apoptotic cell death removes unwanted cells and is regulated by interactions between pro-survival and pro-apoptotic members of the BCL-2 protein family. The regulation of apoptosis is thought to be crucial for normal embryonic development. Accordingly, complete loss of pro-survival MCL-1 or BCL-XL (BCL2L1) causes embryonic lethality. However, it is not known whether minor reductions in pro-survival proteins could cause developmental abnormalities. We explored the rate-limiting roles of MCL-1 and BCL-XL in development and show that combined loss of single alleles of Mcl-1 and Bcl-x causes neonatal lethality. Mcl-1+/-;Bcl-x+/- mice display craniofacial anomalies, but additional loss of a single allele of pro-apoptotic Bim (Bcl2l11) restores normal development. These findings demonstrate that the control of cell survival during embryogenesis is finely balanced and suggest that some human craniofacial defects, for which causes are currently unknown, may be due to subtle imbalances between pro-survival and pro-apoptotic BCL-2 family members.


Assuntos
Proteína 11 Semelhante a Bcl-2/genética , Anormalidades Craniofaciais/genética , Proteína de Sequência 1 de Leucemia de Células Mieloides/genética , Proteína bcl-X/genética , Animais , Apoptose , Proteína 11 Semelhante a Bcl-2/metabolismo , Células Cultivadas , Feminino , Heterozigoto , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Proteína bcl-X/metabolismo
13.
Bioessays ; 40(10): e1800078, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30144132

RESUMO

Histone acetylation has been recognized as an important post-translational modification of core nucleosomal histones that changes access to the chromatin to allow gene transcription, DNA replication, and repair. Histone acetyltransferases were initially identified as co-activators that link DNA-binding transcription factors to the general transcriptional machinery. Over the years, more chromatin-binding modes have been discovered suggesting direct interaction of histone acetyltransferases and their protein complex partners with histone proteins. While much progress has been made in characterizing histone acetyltransferase complexes biochemically, cell-free activity assay results are often at odds with in-cell histone acetyltransferase activities. In-cell studies suggest specific histone lysine targets, but broad recruitment modes, apparently not relying on specific DNA sequences, but on chromatin of a specific functional state. Here we review the evidence for general versus specific roles of individual nuclear lysine acetyltransferases in light of in vivo and in vitro data in the mammalian system.


Assuntos
Genoma , Histona Acetiltransferases/metabolismo , Histonas/metabolismo , Lisina/metabolismo , Acetilação , Animais , Cromatina/metabolismo , Deleção de Genes , Histona Acetiltransferases/genética , Humanos , Lisina Acetiltransferases/genética , Lisina Acetiltransferases/metabolismo , Mamíferos , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Processamento de Proteína Pós-Traducional , RNA Interferente Pequeno
14.
Cell ; 173(5): 1217-1230.e17, 2018 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-29775594

RESUMO

Intrinsic apoptosis, reliant on BAX and BAK, has been postulated to be fundamental for morphogenesis, but its precise contribution to this process has not been fully explored in mammals. Our structural analysis of BOK suggests close resemblance to BAX and BAK structures. Notably, Bok-/-Bax-/-Bak-/- animals exhibited more severe defects and died earlier than Bax-/-Bak-/- mice, implying that BOK has overlapping roles with BAX and BAK during developmental cell death. By analyzing Bok-/-Bax-/-Bak-/- triple-knockout mice whose cells are incapable of undergoing intrinsic apoptosis, we identified tissues that formed well without this process. We provide evidence that necroptosis, pyroptosis, or autophagy does not substantially substitute for the loss of apoptosis. Albeit very rare, unexpected attainment of adult Bok-/-Bax-/-Bak-/- mice suggests that morphogenesis can proceed entirely without apoptosis mediated by these proteins and possibly without cell death in general.


Assuntos
Apoptose , Embrião de Mamíferos/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteína Killer-Antagonista Homóloga a bcl-2/genética , Proteína X Associada a bcl-2/genética , Anormalidades Múltiplas/patologia , Anormalidades Múltiplas/veterinária , Animais , Embrião de Mamíferos/anatomia & histologia , Embrião de Mamíferos/patologia , Desenvolvimento Embrionário/genética , Feto/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteína Killer-Antagonista Homóloga a bcl-2/metabolismo , Proteína X Associada a bcl-2/metabolismo
15.
Hum Mol Genet ; 27(12): 2171-2186, 2018 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-29648665

RESUMO

The human general transcription factor TFIID is composed of the TATA-binding protein (TBP) and 13 TBP-associated factors (TAFs). In eukaryotic cells, TFIID is thought to nucleate RNA polymerase II (Pol II) preinitiation complex formation on all protein coding gene promoters and thus, be crucial for Pol II transcription. In a child with intellectual disability, mild microcephaly, corpus callosum agenesis and poor growth, we identified a homozygous splice-site mutation in TAF8 (NM_138572.2: c.781-1G > A). Our data indicate that the patient's mutation generates a frame shift and an unstable TAF8 mutant protein with an unrelated C-terminus. The mutant TAF8 protein could not be detected in extracts from the patient's fibroblasts, indicating a loss of TAF8 function and that the mutation is most likely causative. Moreover, our immunoprecipitation and proteomic analyses show that in patient cells only partial TAF complexes exist and that the formation of the canonical TFIID is impaired. In contrast, loss of TAF8 in mouse embryonic stem cells and blastocysts leads to cell death and to a global decrease in Pol II transcription. Astonishingly however, in human TAF8 patient cells, we could not detect any cellular phenotype, significant changes in genome-wide Pol II occupancy and pre-mRNA transcription. Thus, the disorganization of the essential holo-TFIID complex did not affect global Pol II transcription in the patient's fibroblasts. Our observations further suggest that partial TAF complexes, and/or an altered TFIID containing a mutated TAF8, could support human development and thus, the absence of holo-TFIID is less deleterious for transcription than originally predicted.


Assuntos
Deficiência Intelectual/genética , Microcefalia/genética , Fator de Transcrição TFIID/genética , Transcrição Genética , Animais , Blastocisto/metabolismo , Morte Celular/genética , Modelos Animais de Doenças , Drosophila/genética , Homozigoto , Humanos , Deficiência Intelectual/diagnóstico por imagem , Deficiência Intelectual/fisiopatologia , Camundongos , Microcefalia/diagnóstico por imagem , Microcefalia/patologia , Células-Tronco Embrionárias Murinas/metabolismo , Mutação , RNA Polimerase II/genética
16.
Cereb Cortex ; 27(1): 576-588, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-26503265

RESUMO

Mutations of the reelin gene cause severe defects in cerebral cortex development and profound intellectual impairment. While many aspects of the reelin signaling pathway have been identified, the molecular and ultimate cellular consequences of reelin signaling remain unknown. Specifically, it is unclear if termination of reelin signaling is as important for normal cortical neuron migration as activation of reelin signaling. Using mice that are single or double deficient, we discovered that combined loss of the suppressors of cytokine signaling, SOCS6 and SOCS7, recapitulated the cortical layer inversion seen in mice lacking reelin and led to a dramatic increase in the reelin signaling molecule disabled (DAB1) in the cortex. The SRC homology domains of SOCS6 and SOCS7 bound DAB1 ex vivo. Mutation of DAB1 greatly diminished binding and protected from degradation by SOCS6. Phosphorylated DAB1 was elevated in cortical neurons in the absence of SOCS6 and SOCS7. Thus, constitutive activation of reelin signaling was observed to be equally detrimental as lack of activation. We hypothesize that, by terminating reelin signaling, SOCS6 and SOCS7 may allow new cycles of reelin signaling to occur and that these may be essential for cortical neuron migration.


Assuntos
Moléculas de Adesão Celular Neuronais/metabolismo , Córtex Cerebral/embriologia , Córtex Cerebral/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Serina Endopeptidases/metabolismo , Proteínas Supressoras da Sinalização de Citocina/deficiência , Animais , Moléculas de Adesão Celular Neuronais/genética , Movimento Celular/fisiologia , Córtex Cerebral/patologia , Proteínas da Matriz Extracelular/genética , Células HEK293 , Humanos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas do Tecido Nervoso/genética , Neurônios/metabolismo , Fosforilação , Serina Endopeptidases/genética , Proteínas Supressoras da Sinalização de Citocina/genética
17.
J Leukoc Biol ; 101(4): 887-892, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-27733580

RESUMO

Histone acetylation has an important role in gene regulation, DNA replication, and repair. Because these processes are central to the development of the immune system, we investigated the role of a previously unstudied histone acetyltransferase named KAT7 (also known as Myst2 or HBO1) in the regulation of thymopoiesis and observed a critical role in the regulation of conventional and innate-like T cell development. We found that KAT7-deficient thymocytes displayed normal, positive selection and development into mature single-positive αß thymocytes; however, we observed few peripheral CD4+ or CD8+ T cells. The observed effects did not appear to arise from alterations to DNA replication, the TCR repertoire, or a block in thymocyte maturation and, more likely, was linked to survival defects related to gene deregulation because KAT7 deficiency led to an almost complete and specific loss of global histone-H3 lysine 14 acetylation (H3K14ac). Overall, we demonstrated a nonredundant role for KAT7 in the maintenance of H3K14ac, which is intimately linked with the ability to develop a normal immune system.


Assuntos
Histona Acetiltransferases/metabolismo , Linfócitos T/citologia , Linfócitos T/enzimologia , Acetilação , Animais , Diferenciação Celular , Sobrevivência Celular , Replicação do DNA , Histona Acetiltransferases/deficiência , Histonas/metabolismo , Células Matadoras Naturais/citologia , Células Matadoras Naturais/metabolismo , Lisina/metabolismo , Camundongos Endogâmicos C57BL , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Timócitos/citologia , Timócitos/metabolismo
18.
Exp Hematol ; 47: 83-97.e8, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-27773671

RESUMO

Chromatin plays a central role in maintaining hematopoietic stem cells and during their stepwise differentiation. Although a large number of histone modifications and chromatin-modifying enzymes have been identified, how these act in concert to produce specific phenotypic outcomes remains to be established. MOZ (KAT6A) is a lysine acetyltransferase and enhances transcription at target gene loci. In contrast, the Polycomb group protein BMI1 (PCGF4) is part of the transcriptionally repressive PRC1 complex. Despite their opposing effects on transcription, MOZ and BMI1 regulate biological systems in a similar manner. MOZ and BMI1 are required for the development of transplantable HSCs, for restraining cellular senescence, for the proper patterning of the anterior-posterior axis during development and for the specification and maintenance of the B-cell lineage. Thus, we set out to explore the relationship between MOZ and BMI1. We recently established that MOZ and BMI1 have opposing effects on the initiation of Hox gene expression during embryonic development and that defects in body segment identity specification observed in single Moz and Bmi1 mutants were rescued in compound mutants. We report here the relationship between MOZ and BMI1 in hematopoiesis. Using Moz+/-;Bmi1+/- compound mutant mice, we found that MOZ and BMI1, but not the BMI1-related protein MEL18 (PCGF2), play synergistic roles in maintaining adult HSCs. Although BMI1 restrains premature senescence, we established that MOZ acts to maintain the quiescent state of HSCs. Our work revealed that MOZ and BMI1 regulate HSCs in a synergistic manner by acting on distinct processes required to maintain HSCs.


Assuntos
Autorrenovação Celular/genética , Epistasia Genética , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Histona Acetiltransferases/genética , Complexo Repressor Polycomb 1/genética , Proteínas Proto-Oncogênicas/genética , Animais , Biomarcadores , Transplante de Medula Óssea , Diferenciação Celular/genética , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Dosagem de Genes , Genótipo , Imunofenotipagem , Camundongos , Camundongos Knockout , Fenótipo
19.
Blood ; 128(19): 2307-2318, 2016 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-27663673

RESUMO

Hematopoietic stem cells (HSCs) are conventionally thought to be at the apex of a hierarchy that produces all mature cells of the blood. The quintessential property of these cells is their ability to reconstitute the entire hematopoietic system of hemoablated recipients. This characteristic has enabled HSCs to be used to replenish the hematopoietic system of patients after chemotherapy or radiotherapy. Here, we use deletion of the monocytic leukemia zinc finger gene (Moz/Kat6a/Myst3) to examine the effects of removing HSCs. Loss of MOZ in adult mice leads to the rapid loss of HSCs as defined by transplantation. This is accompanied by a reduction of the LSK-CD48-CD150+ and LSK-CD34-Flt3- populations in the bone marrow and a reduction in quiescent cells in G0 Surprisingly, the loss of classically defined HSCs did not affect mouse viability, and there was no recovery of the LSK-CD48-CD150+ and LSK-CD34-Flt3- populations 15 to 18 months after Moz deletion. Clonal analysis of myeloid progenitors, which produce short-lived granulocytes, demonstrate that these are derived from cells that had undergone recombination at the Moz locus up to 2 years earlier, suggesting that early progenitors have acquired extended self-renewal. Our results establish that there are essential differences in HSC requirement for steady-state blood cell production compared with the artificial situation of reconstitution after transplantation into a hemoablated host. A better understanding of steady-state hematopoiesis may facilitate the development of novel therapies engaging hematopoietic cell populations with previously unrecognized traits, as well as characterizing potential vulnerability to oncogenic transformation.


Assuntos
Células-Tronco Adultas/citologia , Células-Tronco Adultas/metabolismo , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Histona Acetiltransferases/metabolismo , Animais , Biomarcadores/metabolismo , Células da Medula Óssea/patologia , Contagem de Células , Diferenciação Celular , Senescência Celular , Ensaio de Unidades Formadoras de Colônias , Deleção de Genes , Integrases/metabolismo , Camundongos Endogâmicos C57BL , Fenótipo , Fase de Repouso do Ciclo Celular , Transplante de Células-Tronco
20.
Cell Rep ; 16(12): 3311-3321, 2016 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-27653692

RESUMO

How functionally diverse populations of pathogen-specific killer T cells are generated during an immune response remains unclear. Here, we propose that fine-tuning of CD8αß co-receptor levels via histone acetylation plays a role in lineage fate. We show that lysine acetyltransferase 6A (KAT6A) is responsible for maintaining permissive Cd8 gene transcription and enabling robust effector responses during infection. KAT6A-deficient CD8(+) T cells downregulated surface CD8 co-receptor expression during clonal expansion, a finding linked to reduced Cd8α transcripts and histone-H3 lysine 9 acetylation of the Cd8 locus. Loss of CD8 expression in KAT6A-deficient T cells correlated with reduced TCR signaling intensity and accelerated contraction of the effector-like memory compartment, whereas the long-lived memory compartment appeared unaffected, a result phenocopied by the removal of the Cd8 E8I enhancer element. These findings suggest a direct role of CD8αß co-receptor expression and histone acetylation in shaping functional diversity within the cytotoxic T cell pool.


Assuntos
Antígenos CD8/metabolismo , Linfócitos T CD8-Positivos/imunologia , Histona Acetiltransferases/metabolismo , Memória Imunológica/imunologia , Linfócitos T Citotóxicos/imunologia , Acetilação , Animais , Antígenos CD8/imunologia , Linfócitos T CD8-Positivos/citologia , Diferenciação Celular/imunologia , Linhagem da Célula , Coriomeningite Linfocítica/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Processamento de Proteína Pós-Traducional
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