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1.
Nat Commun ; 11(1): 4782, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32963223

RESUMO

Polycomb and Trithorax group proteins maintain stable epigenetic memory of gene expression states for some genes, but many targets show highly dynamic regulation. Here we combine experiment and theory to examine the mechanistic basis of these different modes of regulation. We present a mathematical model comprising a Polycomb/Trithorax response element (PRE/TRE) coupled to a promoter and including Drosophila developmental timing. The model accurately recapitulates published studies of PRE/TRE mediated epigenetic memory of both silencing and activation. With minimal parameter changes, the same model can also recapitulate experimental data for a different PRE/TRE that allows dynamic regulation of its target gene. The model predicts that both cell cycle length and PRE/TRE identity are critical for determining whether the system gives stable memory or dynamic regulation. Our work provides a simple unifying framework for a rich repertoire of PRE/TRE functions, and thus provides insights into  genome-wide Polycomb/Trithorax regulation.


Assuntos
Proteínas Cromossômicas não Histona/genética , Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Epigenômica , Regulação da Expressão Gênica no Desenvolvimento/genética , Modelos Teóricos , Complexo Repressor Polycomb 1/genética , Animais , Divisão Celular , Proteínas Cromossômicas não Histona/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/fisiologia , Epigênese Genética , Feminino , Inativação Gênica , Complexo Repressor Polycomb 1/metabolismo , Proteínas do Grupo Polycomb/metabolismo , Regiões Promotoras Genéticas , Elementos de Resposta
2.
Mol Cell ; 79(3): 371-375, 2020 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-32763226

RESUMO

Whereas the core nucleosome is thought to serve as a packaging device for the coiling and contraction in length of genomic DNA, we suggest that it serves primarily in the regulation of transcription. A nucleosome on a promoter prevents the initiation of transcription. The association of nucleosomes with most genomic DNA prevents initiation from cryptic promoters. The nucleosome thus serves not only as a general gene repressor, but also as a repressor of all transcription (genic, intragenic, and intergenic). The core nucleosome performs a fundamental regulatory role, apart from the histone "tails," which modulate gene activity.


Assuntos
Proteínas Cromossômicas não Histona/genética , Nucleossomos/metabolismo , RNA Polimerase II/genética , Saccharomyces cerevisiae/genética , Fatores de Transcrição/genética , Transcrição Genética , Animais , Sítios de Ligação , Montagem e Desmontagem da Cromatina , Proteínas Cromossômicas não Histona/metabolismo , Evolução Molecular , Regulação da Expressão Gênica , Histonas/genética , Histonas/metabolismo , Humanos , Nucleossomos/ultraestrutura , Regiões Promotoras Genéticas , RNA Polimerase II/metabolismo , Saccharomyces cerevisiae/metabolismo , Fatores de Transcrição/metabolismo
3.
Nat Commun ; 11(1): 3796, 2020 07 30.
Artigo em Inglês | MEDLINE | ID: mdl-32732900

RESUMO

The ter region of the bacterial chromosome, where replication terminates, is the last to be segregated before cell division in Escherichia coli. Delayed segregation is controlled by the MatP protein, which binds to specific sites (matS) within ter, and interacts with other proteins such as ZapB. Here, we investigate the role of MatP by combining short-time mobility analyses of the ter locus with biochemical approaches. We find that ter mobility is similar to that of a non ter locus, except when sister ter loci are paired after replication. This effect depends on MatP, the persistence of catenanes, and ZapB. We characterise MatP/DNA complexes and conclude that MatP binds DNA as a tetramer, but bridging matS sites in a DNA-rich environment remains infrequent. We propose that tetramerisation of MatP links matS sites with ZapB and/or with non-specific DNA to promote optimal pairing of sister ter regions until cell division.


Assuntos
Proteínas de Ciclo Celular/genética , Proteínas Cromossômicas não Histona/genética , Cromossomos Bacterianos/genética , Proteínas de Escherichia coli/genética , Escherichia coli/genética , Divisão Celular/genética , Proteínas Cromossômicas não Histona/metabolismo , Replicação do DNA/genética , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo
4.
PLoS Genet ; 16(8): e1008962, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32750047

RESUMO

Haspin, a highly conserved kinase in eukaryotes, has been shown to be responsible for phosphorylation of histone H3 at threonine 3 (H3T3ph) during mitosis, in mammals and yeast. Here we report that haspin is the kinase that phosphorylates H3T3 in Drosophila melanogaster and it is involved in sister chromatid cohesion during mitosis. Our data reveal that haspin also phosphorylates H3T3 in interphase. H3T3ph localizes in broad silenced domains at heterochromatin and lamin-enriched euchromatic regions. Loss of haspin compromises insulator activity in enhancer-blocking assays and triggers a decrease in nuclear size that is accompanied by changes in nuclear envelope morphology. We show that haspin is a suppressor of position-effect variegation involved in heterochromatin organization. Our results also demonstrate that haspin is necessary for pairing-sensitive silencing and it is required for robust Polycomb-dependent homeotic gene silencing. Haspin associates with the cohesin complex in interphase, mediates Pds5 binding to chromatin and cooperates with Pds5-cohesin to modify Polycomb-dependent homeotic transformations. Therefore, this study uncovers an unanticipated role for haspin kinase in genome organization of interphase cells and demonstrates that haspin is required for homeotic gene regulation.


Assuntos
Cromatina/genética , Proteínas de Drosophila/genética , Mitose/genética , Proteínas Serina-Treonina Quinases/genética , Animais , Proteínas de Ciclo Celular/genética , Centrômero/genética , Proteínas Cromossômicas não Histona/genética , Segregação de Cromossomos/genética , Drosophila melanogaster/genética , Inativação Gênica , Heterocromatina/genética , Histonas/genética , Interfase/genética , Fosforilação , Proteínas do Grupo Polycomb/genética , Troca de Cromátide Irmã/genética , Treonina/genética
5.
PLoS Genet ; 16(8): e1008990, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32810142

RESUMO

The kinetochore, a multi-protein complex assembled on centromeres, is essential to segregate chromosomes during cell division. Deficiencies in kinetochore function can lead to chromosomal instability and aneuploidy-a hallmark of cancer cells. Kinetochore function is controlled by recruitment of regulatory proteins, many of which have been documented, however their function often remains uncharacterized and many are yet to be identified. To identify candidates of kinetochore regulation we used a proteome-wide protein association strategy in budding yeast and detected many proteins that are involved in post-translational modifications such as kinases, phosphatases and histone modifiers. We focused on the Polo-like kinase, Cdc5, and interrogated which cellular components were sensitive to constitutive Cdc5 localization. The kinetochore is particularly sensitive to constitutive Cdc5 kinase activity. Targeting Cdc5 to different kinetochore subcomplexes produced diverse phenotypes, consistent with multiple distinct functions at the kinetochore. We show that targeting Cdc5 to the inner kinetochore, the constitutive centromere-associated network (CCAN), increases the levels of centromeric RNA via an SPT4 dependent mechanism.


Assuntos
Proteínas de Ciclo Celular/genética , Centrômero/genética , Proteínas Nucleares/genética , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas/genética , Proteínas de Saccharomyces cerevisiae/genética , Fatores de Elongação da Transcrição/genética , Anáfase/genética , Proteínas Cromossômicas não Histona/genética , Segregação de Cromossomos/genética , Histonas/genética , Humanos , Cinetocoros/metabolismo , Mitose/genética , Fenótipo , Fosforilação/genética , RNA/genética , Saccharomyces cerevisiae/genética
6.
Mutat Res ; 785: 108320, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32800274

RESUMO

It is well established that maternal age is associated with a rapid decline in the production of healthy and high-quality oocytes resulting in reduced fertility in women older than 35 years of age. In particular, chromosome segregation errors during meiotic divisions are increasingly common and lead to the production of oocytes with an incorrect number of chromosomes, a condition known as aneuploidy. When an aneuploid oocyte is fertilized by a sperm it gives rise to an aneuploid embryo that, except in rare situations, will result in a spontaneous abortion. As females advance in age, they are at higher risk of infertility, miscarriage, or having a pregnancy affected by congenital birth defects such as Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), and Turner syndrome (monosomy X). Here, we review the potential molecular mechanisms associated with increased chromosome segregation errors during meiosis as a function of maternal age. Our review shows that multiple exogenous and endogenous factors contribute to the age-related increase in oocyte aneuploidy. Specifically, the weight of evidence indicates that recombination failure, cohesin deterioration, spindle assembly checkpoint (SAC) disregulation, abnormalities in post-translational modification of histones and tubulin, and mitochondrial dysfunction are the leading causes of oocyte aneuploidy associated with maternal aging. There is also growing evidence that dietary and other bioactive interventions may mitigate the effect of maternal aging on oocyte quality and oocyte aneuploidy, thereby improving fertility outcomes. Maternal age is a major concern for aneuploidy and genetic disorders in the offspring in the context of an increasing proportion of mothers having children at increasingly older ages. A better understanding of the mechanisms associated with maternal aging leading to aneuploidy and of intervention strategies that may mitigate these detrimental effects and reduce its occurrence are essential for preventing abnormal reproductive outcomes in the human population.


Assuntos
Aneuploidia , Proteínas de Ciclo Celular/genética , Proteínas Cromossômicas não Histona/genética , Segregação de Cromossomos/genética , Anormalidades Congênitas/genética , Idade Materna , Anormalidades Congênitas/prevenção & controle , Feminino , Humanos , Pontos de Checagem da Fase M do Ciclo Celular/genética , Meiose/genética , Mitocôndrias/fisiologia , Oócitos/fisiologia
7.
Mol Cell ; 79(6): 917-933.e9, 2020 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-32755595

RESUMO

Despite key roles in sister chromatid cohesion and chromosome organization, the mechanism by which cohesin rings are loaded onto DNA is still unknown. Here we combine biochemical approaches and cryoelectron microscopy (cryo-EM) to visualize a cohesin loading intermediate in which DNA is locked between two gates that lead into the cohesin ring. Building on this structural framework, we design experiments to establish the order of events during cohesin loading. In an initial step, DNA traverses an N-terminal kleisin gate that is first opened upon ATP binding and then closed as the cohesin loader locks the DNA against the ATPase gate. ATP hydrolysis will lead to ATPase gate opening to complete DNA entry. Whether DNA loading is successful or results in loop extrusion might be dictated by a conserved kleisin N-terminal tail that guides the DNA through the kleisin gate. Our results establish the molecular basis for cohesin loading onto DNA.


Assuntos
Proteínas de Ciclo Celular/ultraestrutura , Cromátides/ultraestrutura , Proteínas Cromossômicas não Histona/ultraestrutura , DNA/ultraestrutura , Troca de Cromátide Irmã/genética , Adenosina Trifosfatases/genética , Proteínas de Ciclo Celular/genética , Cromátides/genética , Proteínas Cromossômicas não Histona/genética , Segregação de Cromossomos/genética , Microscopia Crioeletrônica , DNA/genética , Conformação de Ácido Nucleico , Conformação Proteica , Saccharomyces cerevisiae/ultraestrutura , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/ultraestrutura
8.
PLoS Biol ; 18(8): e3000817, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32813728

RESUMO

During meiosis, chromosomes adopt a specialized organization involving assembly of a cohesin-based axis along their lengths, with DNA loops emanating from this axis. We applied novel, quantitative, and widely applicable cytogenetic strategies to elucidate the molecular bases of this organization using Caenorhabditis elegans. Analyses of wild-type (WT) chromosomes and de novo circular minichromosomes revealed that meiosis-specific HORMA-domain proteins assemble into cohorts in defined numbers and co-organize the axis together with 2 functionally distinct cohesin complexes (REC-8 and COH-3/4) in defined stoichiometry. We further found that REC-8 cohesins, which load during S phase and mediate sister-chromatid cohesion, usually occur as individual complexes, supporting a model wherein sister cohesion is mediated locally by a single cohesin ring. REC-8 complexes are interspersed in an alternating pattern with cohorts of axis-organizing COH-3/4 complexes (averaging 3 per cohort), which are insufficient to confer cohesion but can bind to individual chromatids, suggesting a mechanism to enable formation of asymmetric sister-chromatid loops. Indeed, immunofluorescence/fluorescence in situ hybridization (immuno-FISH) assays demonstrate frequent asymmetry in genomic content between the loops formed on sister chromatids. We discuss how features of chromosome axis/loop architecture inferred from our data can help to explain enigmatic, yet essential, aspects of the meiotic program.


Assuntos
Caenorhabditis elegans/genética , Proteínas de Ciclo Celular/genética , Cromátides/ultraestrutura , Proteínas Cromossômicas não Histona/genética , Cromossomos/ultraestrutura , Meiose , Complexo Sinaptonêmico/ultraestrutura , Animais , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Ciclo Celular/metabolismo , Cromátides/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Segregação de Cromossomos , Cromossomos/metabolismo , Análise Citogenética , Hibridização in Situ Fluorescente , Fase S/genética , Complexo Sinaptonêmico/metabolismo
9.
Nat Commun ; 11(1): 4316, 2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32859932

RESUMO

Plants utilize a UV-B (280 to 315 nm) photoreceptor UVR8 (UV RESISTANCE LOCUS 8) to sense environmental UV levels and regulate gene expression to avoid harmful UV effects. Uniquely, UVR8 uses intrinsic tryptophan for UV-B perception with a homodimer structure containing 26 structural tryptophan residues. However, besides 8 tryptophans at the dimer interface to form two critical pyramid perception centers, the other 18 tryptophans' functional role is unknown. Here, using ultrafast fluorescence spectroscopy, computational methods and extensive mutations, we find that all 18 tryptophans form light-harvesting networks and funnel their excitation energy to the pyramid centers to enhance light-perception efficiency. We determine the timescales of all elementary tryptophan-to-tryptophan energy-transfer steps in picoseconds to nanoseconds, in excellent agreement with quantum computational calculations, and finally reveal a significant leap in light-perception quantum efficiency from 35% to 73%. This photoreceptor is the first system discovered so far, to be best of our knowledge, using natural amino-acid tryptophans to form networks for both light harvesting and light perception.


Assuntos
Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/metabolismo , Proteínas Cromossômicas não Histona/química , Proteínas Cromossômicas não Histona/metabolismo , Fotorreceptores de Plantas/química , Fotorreceptores de Plantas/metabolismo , Arabidopsis/metabolismo , Arabidopsis/fisiologia , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/genética , Proteínas Cromossômicas não Histona/genética , Transferência de Energia , Fluorescência , Cinética , Luz , Modelos Moleculares , Mutação , Conformação Proteica , Multimerização Proteica , Triptofano/metabolismo , Raios Ultravioleta
10.
Nat Commun ; 11(1): 4168, 2020 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-32820162

RESUMO

There is conflicting data regarding the role of PBAF complex mutations and response to immune checkpoint blockade (ICB) therapy in clear cell renal cell carcinoma (ccRCC) and other solid tumors. We assess the prevalence of PBAF complex mutations from two large cohorts including the pan-cancer TCGA project (n = 10,359) and the MSK-IMPACT pan-cancer immunotherapy cohort (n = 3700). Across both cohorts, PBAF complex mutations, predominantly PBRM1 mutations, are most common in ccRCC. In multivariate models of ccRCC patients treated with ICB (n = 189), loss-of-function (LOF) mutations in PBRM1 are not associated with overall survival (OS) (HR = 1.24, p = 0.47) or time to treatment failure (HR = 0.85, p = 0.44). In a series of 11 solid tumors (n = 2936), LOF mutations are not associated with improved OS in a stratified multivariate model (HR = 0.9, p = 0.7). In a current series of solid tumors treated with ICB, we are unable to demonstrate favorable response to ICB in patients with PBAF complex mutations.


Assuntos
Carcinoma de Células Renais/terapia , Proteínas Cromossômicas não Histona/genética , Proteínas de Ligação a DNA/genética , Imunoterapia/métodos , Neoplasias Renais/terapia , Mutação , Fatores de Transcrição/genética , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Renais/genética , Carcinoma de Células Renais/patologia , Estudos de Coortes , Regulação Neoplásica da Expressão Gênica , Humanos , Estimativa de Kaplan-Meier , Neoplasias Renais/genética , Neoplasias Renais/patologia , Pessoa de Meia-Idade
11.
PLoS One ; 15(7): e0235705, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32649682

RESUMO

Mutations of the SWI/SNF chromatin remodeling complex occur in 20% of all human cancers, including ovarian cancer. Approximately half of ovarian clear cell carcinomas (OCCC) carry mutations in the SWI/SNF subunit ARID1A, while small cell carcinoma of the ovary hypercalcemic type (SCCOHT) presents with inactivating mutations of the SWI/SNF ATPase SMARCA4 alongside epigenetic silencing of the ATPase SMARCA2. Loss of these ATPases disrupts SWI/SNF chromatin remodeling activity and may also interfere with the function of other histone-modifying enzymes that associate with or are dependent on SWI/SNF activity. One such enzyme is lysine-specific histone demethylase 1 (LSD1/KDM1A), which regulates the chromatin landscape and gene expression by demethylating proteins such as histone H3. Cross-cancer analysis of the TCGA database shows that LSD1 is highly expressed in SWI/SNF-mutated tumors. SCCOHT and OCCC cell lines have shown sensitivity to the reversible LSD1 inhibitor SP-2577 (Seclidemstat), suggesting that SWI/SNF-deficient ovarian cancers are dependent on LSD1 activity. Moreover, it has been shown that inhibition of LSD1 stimulates interferon (IFN)-dependent anti-tumor immunity through induction of endogenous retroviral elements and may thereby overcome resistance to checkpoint blockade. In this study, we investigated the ability of SP-2577 to promote anti-tumor immunity and T-cell infiltration in SCCOHT and OCCC cell lines. We found that SP-2577 stimulated IFN-dependent anti-tumor immunity in SCCOHT and promoted the expression of PD-L1 in both SCCOHT and OCCC. Together, these findings suggest that the combination therapy of SP-2577 with checkpoint inhibitors may induce or augment immunogenic responses of SWI/SNF-mutated ovarian cancers and warrants further investigation.


Assuntos
Antineoplásicos/farmacologia , Proteínas Cromossômicas não Histona/genética , Proteínas de Ligação a DNA/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Linfócitos T/efeitos dos fármacos , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/genética , Antígeno B7-H1/genética , Antígeno B7-H1/metabolismo , Carcinoma de Células Pequenas/genética , Carcinoma de Células Pequenas/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Meios de Cultivo Condicionados/química , Meios de Cultivo Condicionados/farmacologia , DNA Helicases/genética , DNA Helicases/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Histonas/genética , Histonas/metabolismo , Humanos , Interferons/farmacologia , Mutação , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/imunologia , Neoplasias Ovarianas/patologia , Linfócitos T/citologia , Linfócitos T/imunologia , Fatores de Transcrição/metabolismo
12.
PLoS Genet ; 16(7): e1008900, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32667955

RESUMO

In this study we performed a genotype-phenotype association analysis of meiotic stability in 10 autotetraploid Arabidopsis lyrata and A. lyrata/A. arenosa hybrid populations collected from the Wachau region and East Austrian Forealps. The aim was to determine the effect of eight meiosis genes under extreme selection upon adaptation to whole genome duplication. Individual plants were genotyped by high-throughput sequencing of the eight meiosis genes (ASY1, ASY3, PDS5b, PRD3, REC8, SMC3, ZYP1a/b) implicated in synaptonemal complex formation and phenotyped by assessing meiotic metaphase I chromosome configurations. Our results reveal that meiotic stability varied greatly (20-100%) between individual tetraploid plants and associated with segregation of a novel ASYNAPSIS3 (ASY3) allele derived from A. lyrata. The ASY3 allele that associates with meiotic stability possesses a putative in-frame tandem duplication (TD) of a serine-rich region upstream of the coiled-coil domain that appears to have arisen at sites of DNA microhomology. The frequency of multivalents observed in plants homozygous for the ASY3 TD haplotype was significantly lower than in plants heterozygous for ASY3 TD/ND (non-duplicated) haplotypes. The chiasma distribution was significantly altered in the stable plants compared to the unstable plants with a shift from proximal and interstitial to predominantly distal locations. The number of HEI10 foci at pachytene that mark class I crossovers was significantly reduced in a plant homozygous for ASY3 TD compared to a plant heterozygous for ASY3 ND/TD. Fifty-eight alleles of the 8 meiosis genes were identified from the 10 populations analysed, demonstrating dynamic population variability at these loci. Widespread chimerism between alleles originating from A. lyrata/A. arenosa and diploid/tetraploids indicates that this group of rapidly evolving genes may provide precise adaptive control over meiotic recombination in the tetraploids, the very process that gave rise to them.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Proteínas Cromossômicas não Histona/genética , Meiose/genética , Alelos , Arabidopsis/crescimento & desenvolvimento , Pareamento Cromossômico/genética , Segregação de Cromossomos , Cromossomos de Plantas/genética , Proteínas de Ligação a DNA/genética , Diploide , Tetraploidia
13.
Gene ; 758: 144966, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-32687945

RESUMO

RAD21 (also known as KIAA0078, NXP1, HR21, Mcd1, Scc1, and hereafter called RAD21), an essential gene, encodes a DNA double-strand break (DSB) repair protein that is evolutionarily conserved in all eukaryotes from budding yeast to humans. RAD21 protein is a structural component of the highly conserved cohesin complex consisting of RAD21, SMC1a, SMC3, and SCC3 [STAG1 (SA1) and STAG2 (SA2) in metazoans] proteins, involved in sister chromatid cohesion. This function is essential for proper chromosome segregation, post-replicative DNA repair, and prevention of inappropriate recombination between repetitive regions. In interphase, cohesin also functions in the control of gene expression by binding to numerous sites within the genome. In addition to playing roles in the normal cell cycle and DNA DSB repair, RAD21 is also linked to the apoptotic pathways. Germline heterozygous or homozygous missense mutations in RAD21 have been associated with human genetic disorders, including developmental diseases such as Cornelia de Lange syndrome (CdLS) and chronic intestinal pseudo-obstruction (CIPO) called Mungan syndrome, respectively, and collectively termed as cohesinopathies. Somatic mutations and amplification of the RAD21 have also been widely reported in both human solid and hematopoietic tumors. Considering the role of RAD21 in a broad range of cellular processes that are hot spots in neoplasm, it is not surprising that the deregulation of RAD21 has been increasingly evident in human cancers. Herein, we review the biology of RAD21 and the cellular processes that this important protein regulates and discuss the significance of RAD21 deregulation in cancer and cohesinopathies.


Assuntos
Proteínas de Ciclo Celular/genética , Proteínas Cromossômicas não Histona/genética , Reparo do DNA/genética , Proteínas de Ligação a DNA/genética , Neoplasias/genética , Apoptose/genética , Esôfago de Barrett/genética , Quebras de DNA de Cadeia Dupla , Síndrome de Cornélia de Lange/genética , Hematopoese/genética , Humanos , Pseudo-Obstrução Intestinal/genética , Meiose/genética , Neoplasias/patologia
14.
Nat Commun ; 11(1): 2725, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32483152

RESUMO

The functional study of lncRNAs in skeletal muscle satellite cells (SCs) remains at the infancy stage. Here we identify SAM (Sugt1 asssociated muscle) lncRNA that is enriched in the proliferating myoblasts. Global deletion of SAM has no overt effect on mice but impairs adult muscle regeneration following acute damage; it also exacerbates the chronic injury-induced dystrophic phenotype in mdx mice. Consistently, inducible deletion of SAM in SCs leads to deficiency in muscle regeneration. Further examination reveals that SAM loss results in a cell-autonomous defect in the proliferative expansion of myoblasts. Mechanistically, we find SAM interacts and stabilizes Sugt1, a co-chaperon protein key to kinetochore assembly during cell division. Loss of SAM or Sugt1 both disrupts kinetochore assembly in mitotic cells due to the mislocalization of two components: Dsn1 and Hec1. Altogether, our findings identify SAM as a regulator of SC proliferation through facilitating Sugt1 mediated kinetochore assembly during cell division.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas de Ciclo Celular/genética , Proliferação de Células/genética , Cinetocoros/metabolismo , Mioblastos/metabolismo , RNA Longo não Codificante/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular , Células Cultivadas , Proteínas Cromossômicas não Histona/genética , Proteínas Cromossômicas não Histona/metabolismo , Regulação da Expressão Gênica , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos mdx , Camundongos Knockout , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Mioblastos/citologia , Estabilidade Proteica , Células Satélites de Músculo Esquelético/citologia , Células Satélites de Músculo Esquelético/metabolismo
15.
Science ; 368(6497): 1386-1392, 2020 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-32554597

RESUMO

The nucleus contains diverse phase-separated condensates that compartmentalize and concentrate biomolecules with distinct physicochemical properties. Here, we investigated whether condensates concentrate small-molecule cancer therapeutics such that their pharmacodynamic properties are altered. We found that antineoplastic drugs become concentrated in specific protein condensates in vitro and that this occurs through physicochemical properties independent of the drug target. This behavior was also observed in tumor cells, where drug partitioning influenced drug activity. Altering the properties of the condensate was found to affect the concentration and activity of drugs. These results suggest that selective partitioning and concentration of small molecules within condensates contributes to drug pharmacodynamics and that further understanding of this phenomenon may facilitate advances in disease therapy.


Assuntos
Antineoplásicos/farmacologia , Núcleo Celular/metabolismo , Resistencia a Medicamentos Antineoplásicos , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Antineoplásicos/uso terapêutico , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas Cromossômicas não Histona/genética , Proteínas Cromossômicas não Histona/metabolismo , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Humanos , Subunidade 1 do Complexo Mediador/genética , Subunidade 1 do Complexo Mediador/metabolismo , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Fatores de Processamento de Serina-Arginina/genética , Fatores de Processamento de Serina-Arginina/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
16.
Clin Sci (Lond) ; 134(12): 1457-1472, 2020 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-32514535

RESUMO

The chromatin remodeling complex SWI/SNF regulates the accessibility of target genes to transcription factors and plays a critical role in the tumorigenesis of hepatocellular carcinoma (HCC). The SWI/SNF complex is assembled from approximately 15 subunits, and most of these subunits have distinct roles and are often aberrantly expressed in HCC. A comprehensive exploration of the expression and clinical significance of these subunits would be of great value. In the present study, we obtained the gene expression profile of each SWI/SNF subunit and the corresponding clinical information from The Cancer Genome Atlas (TCGA). We found that 14 out of the 15 SWI/SNF subunits were significantly increased in HCC tissues compared with paired normal liver tissues, and 11 subunits were significantly associated with overall survival (OS). We identified a four-gene prognostic signature including actin-like 6A (ACTL6A), AT-rich interaction domain 1A (ARID1A), SWI/SNF related, matrix associated, actin dependent regulator of chromatin subfamily C member 1 (SMARCC1) and SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily D, member 1 (SMARCD1) that could effectively predict OS in HCC patients. Among the genes, SMARCD1 has the most prognostic value. We further conducted in vitro and in vivo experiments and revealed that SMARCD1 promotes liver cancer growth by activating the mTOR signaling pathway. In conclusion, our study has revealed that the expression of SWI/SNF complex subunits, especially SMARCD1, is highly associated with HCC development and acts as a promising prognostic predictor.


Assuntos
Proteínas Cromossômicas não Histona/metabolismo , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Subunidades Proteicas/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Animais , Linhagem Celular Tumoral , Proliferação de Células , Proteínas Cromossômicas não Histona/genética , Estudos de Coortes , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Hepáticas/genética , Masculino , Camundongos Endogâmicos BALB C , Camundongos Nus , Pessoa de Meia-Idade , Prognóstico , Subunidades Proteicas/genética , Transdução de Sinais , Resultado do Tratamento
17.
Nucleic Acids Res ; 48(13): 7483-7501, 2020 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-32510132

RESUMO

The MLE DExH helicase and the roX lncRNAs are essential components of the chromatin modifying Dosage Compensation Complex (DCC) in Drosophila. To explore the mechanism of ribonucleoprotein complex assembly, we developed vitRIP, an unbiased, transcriptome-wide in vitro assay that reveals RNA binding specificity. We found that MLE has intrinsic specificity for U-/A-rich sequences and tandem stem-loop structures and binds many RNAs beyond roX in vitro. The selectivity of the helicase for physiological substrates is further enhanced by the core DCC. Unwinding of roX2 by MLE induces a highly selective RNA binding surface in the unstructured C-terminus of the MSL2 subunit and triggers-specific association of MLE and roX2 with the core DCC. The exquisite selectivity of roX2 incorporation into the DCC thus originates from intimate cooperation between the helicase and the core DCC involving two distinct RNA selection principles and their mutual refinement.


Assuntos
Montagem e Desmontagem da Cromatina , RNA Longo não Codificante/metabolismo , Transcriptoma , Animais , Proteínas Cromossômicas não Histona/genética , Proteínas Cromossômicas não Histona/metabolismo , Clonagem Molecular/métodos , DNA Helicases/genética , DNA Helicases/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster , Ligação Proteica , RNA Longo não Codificante/genética , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
18.
Nat Commun ; 11(1): 2379, 2020 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-32404872

RESUMO

Brown and beige fat share a remarkably similar transcriptional program that supports fuel oxidation and thermogenesis. The chromatin-remodeling machinery that governs genome accessibility and renders adipocytes poised for thermogenic activation remains elusive. Here we show that BAF60a, a subunit of the SWI/SNF chromatin-remodeling complexes, serves an indispensable role in cold-induced thermogenesis in brown fat. BAF60a maintains chromatin accessibility at PPARγ and EBF2 binding sites for key thermogenic genes. Surprisingly, fat-specific BAF60a inactivation triggers more pronounced cold-induced browning of inguinal white adipose tissue that is linked to induction of MC2R, a receptor for the pituitary hormone ACTH. Elevated MC2R expression sensitizes adipocytes and BAF60a-deficient adipose tissue to thermogenic activation in response to ACTH stimulation. These observations reveal an unexpected dichotomous role of BAF60a-mediated chromatin remodeling in transcriptional control of brown and beige gene programs and illustrate a pituitary-adipose signaling axis in the control of thermogenesis.


Assuntos
Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/metabolismo , Cromatina/metabolismo , Proteínas Cromossômicas não Histona/deficiência , Temperatura Baixa , Adipócitos Marrons/efeitos dos fármacos , Adipócitos Marrons/metabolismo , Adipócitos Marrons/ultraestrutura , Tecido Adiposo Bege/metabolismo , Tecido Adiposo Marrom/efeitos dos fármacos , Tecido Adiposo Branco/efeitos dos fármacos , Hormônio Adrenocorticotrópico/farmacologia , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Sítios de Ligação/genética , Células Cultivadas , Cromatina/genética , Proteínas Cromossômicas não Histona/genética , Expressão Gênica/efeitos dos fármacos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Termogênese/efeitos dos fármacos , Termogênese/genética
19.
PLoS Genet ; 16(5): e1008797, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32392219

RESUMO

Sun-loving plants perceive the proximity of potential light-competing neighboring plants as a reduction in the red:far-red ratio (R:FR), which elicits a suite of responses called the "shade avoidance syndrome" (SAS). Changes in R:FR are primarily perceived by phytochrome B (phyB), whereas UV-B perceived by UV RESISTANCE LOCUS 8 (UVR8) elicits opposing responses to provide a counterbalance to SAS, including reduced shade-induced hypocotyl and petiole elongation. Here we show at the genome-wide level that UVR8 broadly suppresses shade-induced gene expression. A subset of this gene regulation is dependent on the UVR8-stabilized atypical bHLH transcription regulator LONG HYPOCOTYL IN FAR-RED 1 (HFR1), which functions in part redundantly with PHYTOCHROME INTERACTING FACTOR 3-LIKE 1 (PIL1). In parallel, UVR8 signaling decreases protein levels of the key positive regulators of SAS, namely the bHLH transcription factors PHYTOCHROME INTERACTING FACTOR 4 (PIF4) and PIF5, in a COP1-dependent but HFR1-independent manner. We propose that UV-B antagonizes SAS via two mechanisms: degradation of PIF4 and PIF5, and HFR1- and PIL1-mediated inhibition of PIF4 and PIF5 function. This work highlights the importance of typical and atypical bHLH transcription regulators for the integration of light signals from different photoreceptors and provides further mechanistic insight into the crosstalk of UVR8 signaling and SAS.


Assuntos
Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Arabidopsis/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/química , Proteínas Cromossômicas não Histona/genética , Proteínas de Ligação a DNA/química , Raios Ultravioleta/efeitos adversos , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Cromatina/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Regulação para Baixo , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Estabilidade Proteica , Proteólise , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo
20.
PLoS One ; 15(5): e0232789, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32407325

RESUMO

BAHD1 is a heterochomatinization factor recently described as a component of a multiprotein complex associated with histone deacetylases HDAC1/2. The physiological and patho-physiological functions of BAHD1 are not yet well characterized. Here, we examined the consequences of BAHD1 deficiency in the brains of male mice. While Bahd1 knockout mice had no detectable defects in brain anatomy, RNA sequencing profiling revealed about 2500 deregulated genes in Bahd1-/- brains compared to Bahd1+/+ brains. A majority of these genes were involved in nervous system development and function, behavior, metabolism and immunity. Exploration of the Allen Brain Atlas and Dropviz databases, assessing gene expression in the brain, revealed that expression of the Bahd1 gene was limited to a few territories and cell subtypes, particularly in the hippocampal formation, the isocortex and the olfactory regions. The effect of partial BAHD1 deficiency on behavior was then evaluated on Bahd1 heterozygous male mice, which have no lethal or metabolic phenotypes. Bahd1+/- mice showed anxiety-like behavior and reduced prepulse inhibition (PPI) of the startle response. Altogether, these results suggest that BAHD1 plays a role in chromatin-dependent gene regulation in a subset of brain cells and support recent evidence linking genetic alteration of BAHD1 to psychiatric disorders in a human patient.


Assuntos
Ansiedade/genética , Encéfalo/metabolismo , Proteínas Cromossômicas não Histona/genética , Reflexo de Sobressalto/genética , Animais , Ansiedade/fisiopatologia , Encéfalo/patologia , Cromatina/genética , Regulação da Expressão Gênica/genética , Haploinsuficiência/genética , Histona Desacetilase 1/genética , Histona Desacetilase 2/genética , Humanos , Camundongos , Camundongos Knockout , Fenótipo , Análise de Sequência de RNA
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