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The stability and function of eukaryotic genomes is closely linked to histones and to chromatin structure. The state of the chromatin not only affects the probability of DNA to undergo damage but also DNA repair. DNA damage can result in genetic alterations and subsequent development of cancer and other genetic diseases. Here, we identified two mutations in conserved residues of histone H3 and histone H4 (H3E73Q and H4E53A) that increase recombinogenic DNA damage. Our results suggest that the accumulation of DNA damage in these histone mutants is largely independent on transcription and might arise as a consequence of problems occurring during DNA replication. This study uncovers the relevance of H3E73 and H4E53 residues in the protection of genome integrity., Research was supported by the European Research Council (ERC2014 AdG669898 TARLOOP), the Spanish Ministry of Economy and Competitiveness (BFU2016-75058-P), the Foundation Vencer el Cáncer and the European Union (FEDER). P. O. was supported by a predoctoral training grant from the Spanish Ministry of Economy and Competitiveness and B.G.-G. by the Span-ish Association Against Cancer (AECC).

Post-translational histone modifications and chromatin remodelling play a critical role controlling the integrity of the genome. Here, we identify histone lysine demethylase PHF2 as a novel regulator of the DNA damage response by regulating DNA damage-induced focus formation of 53BP1 and BRCA1, critical factors in the pathway choice for DNA double strand break repair. PHF2 knockdown leads to impaired BRCA1 focus formation and delays the resolution of 53BP1 foci. Moreover, irradiation-induced RPA phosphorylation and focus formation, as well as localization of CtIP, required for DNA end resection, to sites of DNA lesions are affected by depletion of PHF2. These results are indicative of a defective resection of double strand breaks and thereby an impaired homologous recombination upon PHF2 depletion. In accordance with these data, Rad51 focus formation and homology-directed double strand break repair is inhibited in cells depleted for PHF2. Importantly, we demonstrate that PHF2 knockdown decreases CtIP and BRCA1 protein and mRNA levels, an effect that is dependent on the demethylase activity of PHF2. Furthermore, PHF2-depleted cells display genome instability and are mildly sensitive to the inhibition of PARP. Together these results demonstrate that PHF2 promotes DNA repair by homologous recombination by controlling CtIP-dependent resection of double strand breaks., Ministerio de Ciencia e Innovación [SAF2016-80626-R to V.A.J.S./R.F., SAF2016-74855-P to P.H. and BFU2017-90889-REDT to V.A.J.S./P.H.], co-funded by EU-ERDF; Fundación Canaria Instituto de Investigación Sanitaria de Canarias (FIISC) [PIFUN16/18 to V.A.J.S.]; I.A.V. is supported by a predoctoral fellowship from the Gobierno de Canarias; J.R.H.F. by the Asociación Española Contra el Cáncer; H.v.A. by an ERC Consolidator grant from the European Research Council and a VICI grant from the Netherlands Organisation for Scientific Research. Funding for open access charge: FIISC [PIFUN16/18]; Ministerio de Ciencia e Innovación [SAF2016-80626-R].

Fundação de Amparo a Pesquisa do Estado de Minas Gerais Several functions have been attributed to the addition of glycidyl radicals in nuclear proteins. It is believed that the structural and functional changes through which they pass along the neurons of aging are associated with different patterns of protein glycosylation in the nucleus of these cells. Previous data refer that the glycosylation of nuclear proteins, mainly histones, plays an important role in epigenetic control of nuclear functions. In this context, the changes in chromatin structure epigenetic changes associates with type O-glycosylation depend, for example, the chromatin remodeling complex recruitment necessary for regulating gene transcription, with this type of control over the aging-related rise neurodegenerative diseases such as Alzheimer s disease and others. Thus, to understand the association between changes in chromatin structure due to O-glycosylation of histones and aging is critical to the development of treatments that can improve the quality of life of the population. For this purpose, it propose to study the in situ distribution of two types of sugar residues attached to proteins, as well as histones are glycosylated and if there differential glycosylation of the proteins along with aging. To this end, isolated neuronal nuclei were underwent cytochemical analysis, and biochemical assays to identify and quantify reactive glycidiy markers to ConA and WGA lectins. Results indicate that glycoproteins containing glucose / mannose and Nacetylglucosamine have differences in their pattern of nuclear distribuition, which depend on the animal age, indicating different functions depending on the composition glicidic of these glycoproteins. Our data show that all canonical (H2A, H2B, H3 e H4) in neurons are glycosylated, with different patterns are observed for each different ages. It is believed that these changes are related to structural changes in chromatin observed during the aging period, which may have a fundamental role in altered patterns of gene expression observed with increasing age. Diversas funções têm sido atribuídas à adição de radicais glicídicos em proteínas nucleares. Acredita-se que as mudanças estruturais e funcionais pelas quais passam os neurônios ao longo do envelhecimento estejam associadas com diferentes padrões de glicosilação protéica no núcleo dessas células. Estudos anteriores remetem que a glicosilação de proteínas nucleares, principalmente histonas, tem um importante papel epigenético no controle das funções nucleares. Nesse contexto, as alterações na estrutura da cromatina associadas com modificações epigenéticas tipo O-glicosilação dependem, por exemplo, do recrutamento de complexos de remodelamento da cromatina necessários à regulação da transcrição gênica, estando esse tipo de controle, ao longo do envelhecimento relacionado ao surgimento de doenças neurodegenerativas, como o mal de Alzheimer e outras. Dessa forma, entender a associação entre as mudanças da estrutura cromatínica devido à O-glicosilação de histonas e o envelhecimento é fundamental para o desenvolvimento de tratamentos que possam melhorar a qualidade de vida da população. Nesse sentido, este trabalho objetivou estudar a distribuição in situ de dois tipos de resíduos de açúcar ligados a proteínas, bem como se as histonas são glicosiladas e se há glicosilação diferencial dessas proteínas ao longo do envelhecimento em núcleos de neurônios corticais de camundongos. Para tanto, núcleos isolados de neurônios foram submetidos à análise citoquímica e ensaios bioquímicos para identificação e quantificação de marcadores glicídicos reativos às lectinas ConA e WGA. Os resultados demonstram que glicoproteínas contendo glicose/manose ou N-acetilglicosamina possuem diferenças no seu padrão de distribuição nuclear, que independem da idade do animal, evidenciando funções diferenciadas dependendo da composição glicídica dessas glicoproteínas. Adicionalmente, os dados indicam que todas as histonas canônicas (H2A, H2B, H3 e H4) são glicosiladas em neurônios, sendo que padrões diferenciados de marcação foram observados em cada uma delas para as diferentes idades. Acredita-se que tais alterações estejam relacionadas com as mudanças estruturais observadas na cromatina ao longo do envelhecimento, as quais podem ter um papel fundamental nos padrões alterados de expressão gênica observados com o avanço da idade. Mestre em Biologia Celular e Estrutural Aplicadas

34 pags., 8 figs. (+SI), The Akirin family of transcription cofactors are involved throughout the metazoan in the regulation of different biological processes (BPs) such as immunity, interdigital regression, muscle and neural development. Akirin do not have catalytic or DNA-binding capability and exert its regulatory function primarily through interacting proteins such as transcription factors, chromatin remodelers, and RNA-associated proteins. In the present study, we focused on the human Akirin2 regulome and interactome in neutrophil-like model human Caucasian promyelocytic leukemia HL60 cells. Our hypothesis is that metazoan evolved to have Akirin2 functional complements and different Akirin2-mediated mechanisms for the regulation of gene expression. To address this hypothesis, experiments were conducted using transcriptomics, proteomics and systems biology approaches in akirin2 knockdown and wildtype (WT) HL60 cells to characterize Akirin2 gene/protein targets, functional complements and to provide evidence of different mechanisms that may be involved in Akirin2-mediated regulation of gene expression. The results revealed Akirin2 gene/protein targets in multiple BPs with higher representation of immunity and identified immune response genes as candidate Akirin2 functional complements. In addition to linking chromatin remodelers with transcriptional activation, Akirin2 also interacts with histone H3.1 for regulation of gene expression., This work was supported by the Ministerio de Economıa, Industria y Competitividad (Spain) [grant number BFU2016-79892-P]; the Predoctoral Fellowship of the UCLM (to Sara Artigas-Jeronimo); the University of Castilla La Mancha, Spain (to Margarita ´ Villar); and the Fondo Europeo de Desarrollo Regional, FEDER, EU (to Margarita Villar).

Glioma stem cells (GSCs) are crucial in the formation, perpetuation and recurrence of glioblastomas (GBs) due to their self-renewal and proliferation properties. Although GSCs share cellular and molecular characteristics with neural stem cells (NSCs), GSCs show unique transcriptional and epigenetic features that may explain their relevant role in GB and may constitute druggable targets for novel therapeutic approaches. In this review, we will summarize the most important findings in GSCs concerning epigenetic-dependent mechanisms. Yes

Emerging evidence has suggested global histone H4 acetylation status plays an important role in neural plasticity. For instance, the imbalance of this epigenetic marker has been hypothesized as a key factor for the development and progression of several neurological diseases. Likewise, astrocytic reactivity - a well-known process that markedly influences the tissue remodeling after a central nervous system injury - is crucial for tissue remodeling after spinal cord injury (SCI). However, the linkage between the above-mentioned mechanisms after SCI remains poorly understood. We sought to investigate the relation between both glial fibrillary acidic protein (GFAP) and S100 calcium-binding protein B (S100B) (astrocytic reactivity classical markers) and global histone H4 acetylation levels. Sixty-one male Wistar rats (aged ~3 months) were divided into the following groups: sham; 6 hours post-SCI; 24 hours post-SCI; 48 hours post-SCI; 72 hours post-SCI; and 7 days post-SCI. The results suggested that GFAP, but not S100B was associated with global histone H4 acetylation levels. Moreover, global histone H4 acetylation levels exhibited a complex pattern after SCI, encompassing at least three clearly defined phases ( first phase: no changes in the 6, 24 and 48 hours post-SCI groups; second phase: increased levels in the 72 hours post-SCI group; and a third phase: return to levels similar to control in the 7 days post-SCI group). Overall, these findings suggest global H4 acetylation levels exhibit distinct patterns of expression during the first week post-SCI, which may be associated with GFAP levels in the perilesional tissue. Current data encourage studies using H4 acetylation as a possible biomarker for tissue remodeling after spinal cord injury.

Producción Científica, Epigenetic marks are modest chemical modifications on DNA and histone proteins that regulate the activation or silencing of genes through modulation of the intermolecular interactions between the DNA strands and the protein machinery. The process is complex and not always well understood. One of the systems studied in greater detail is the epigenetic mark on H3K9: lysine 9 of histone 3. The degree of methylation or acetylation of this histone is linked to silencing or activation of the corresponding gene, but it is not clear which effect each mark has in gene expression. We shed light on this particular methylation process by using density functional theory (DFT) calculations. First, we built a model consisting of a DNA double strand containing three base pairs and a sequence of three amino acids of the histone's tail. Then, we computed the modulation introduced into the intermolecular interactions by each epigenetic modification: from mono- to trimethylation and acetylation. The calculations show that whereas acetylation and trimethylation result in a reduction of the DNA-peptide interaction; non-, mono-, and dimethylation increase the intermolecular interactions. Such observations compare well with the findings reported in the literature, and highlight the correlation between the balance of intermolecular forces and biological properties, simultaneously advancing quantum-mechanical studies of large biochemical systems at molecular level through the use of DFT methods., Ministerio de Economía, Industria y Competitividad - Fondo Europeo de Desarrollo Regional (grants PGC2018-098561-B and UNLR-094E2C-225), Gobierno Vasco (grant IIT62-19)

CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico FAPEMIG - Fundação de Amparo a Pesquisa do Estado de Minas Gerais Os estudos sobre epigenética no carcinoma de células escamosas de boca (CCEB) são raros. As modificações pós-traducionais de histonas (MPTHs) são reguladores essenciais da expressão gênica e estão desreguladas nos cânceres. Nesse estudo, objetivou-se avaliar a expressão de demetilação de H3K4 (H3K4me2), trimetilação de H3K4 (H3K4me3) e acetilação de H3K14 (H3K14ac) no CCEB e a relação delas com metástase e sobrevida. Amostras parafinadas de 90 casos de CCEB foram obtidas e submetidas à marcação imuno-histoquímica com os anticorpos anti-H3K4me2, anti-H3K4me3 e anti-H3K14ac. Para determinar seu papel na metástase, os pacientes foram divididos em tumores primários não metastáticos (PNM) e primários metastáticos (PM). Todas as imunomarcações foram avaliadas usando o software Image J e as expressões nucleares aferidas de acordo com o índice de densidade ótica integrada (IOD). A expressão de cada MPTH foi comparada entre PNM e PM, análises de correlação entre elas e as características clinicopatológicas foram investigadas. Testes de sensibilidade e especificidade foram estabelecidos para cada MPTH através da curva ROC; sendo a curva também usada para estabelecer o cut off de cada modificação e distinguir entre tumores com alta e baixa expressão. Curvas de sobrevida e análises univariada e multivariada também foram empregadas. A positividade das células tumorais foi nuclear. A mediana da expressão de H3K14ac foi significativamente maior no grupo PM. O aumento de H3K4me3 foi correlacionado com tabagismo, diferenciação tumoral e sobrevida. Além disso, altos expressão de H3K4me3 tiveram um impacto negativo na sobrevivência dos pacientes. A curva ROC mostrou que a H3K14ac apresentou a maior sensibilidade (81,3%), sugerindo o uso desta como ferramenta de triagem de pacientes com potencial de desenvolver metástases (N0). Nenhuma das MPTHs mostrou ser um fator de prognóstico independente pela análise multivariada. A avaliação conjunta dos níveis de expressão das MPTHs mostrou que a combinação de baixos níveis de H3K4me2, altos H3K4me3 e altos H3k14ac afetaram significativamente a sobrevivência do grupo PM. Em conclusão, nossos achados mostraram que H3K14ac estava altamente expressa no grupo PM. Altos níveis de H3K4me3 diminuíram a sobrevida dos pacientes, além do aumento desta estar correlacionado aos pacientes tabagistas e também com tumores menos diferenciados. Studies on epigenetics in oral squamous cell carcinoma (OSCC) are rare. Post-translational histone modifications (MPTHs) are essential regulators of gene expression and are deregulated in cancers. In this research we investigated the expression of demethylation of H3K4 (H3K4me2), trimethylation of H3K4 (H3K4me3) and acetylation of H3K14 (H3K14ac) in OSCC and their relationship with metastasis and survival. Paraffin-embedded tissue samples of 90 OSCC patients were raised and submitted to immunohistochemical staining with the antibodies against H3K4me2, H3K4me3 and H3K14ac. To determine their role in metastasis, OSCC patients were divided into two groups: primary non-metastatic tumors (PNM) and primary metastatic ones (PM). The nuclear MPTHs expression was measured according to the integrated optical density index (IOD) by using the software Image J. The expression of each MPTH was compared between the PNM and PM groups; correlation analyzes between them and the clinicopathological characteristics were also investigated. Sensitivity and specificity tests were established for each MPTH through the ROC curve; The ROC curve was also used to establish the cutoff point for each MPTH in order to distinguish high and low-expressing MPHT tumors. Survival curves and univariate and multivariate analyzes were also employed. All tumor cells were positive in the nucleus. Median H3K14ac expression was significantly higher in the PM group. An increased H3K4me3 expression was correlated with smoking, tumor differentiation and reduced survival. In addition, high levels of H3K4me3 had a negative impact on patient’s survival. The ROC curve showed that H3K14ac had the highest sensitivity (81.3%), suggesting that it might be used as a screening test for detecting N0 OSCC patients with great potential to develop metastasis during the course of their diseases. None of the MPTHs showed to be an independent prognostic factor in the multivariate analysis. A combination of MPTHs expression levels showed that low H3K4me2, high H3K4me3 and high H3k14ac expression significantly affected the patients’ survival from the PM group. In conclusion, our findings showed that H3K14ac was highly expressed in the PM group. High levels of H3K4me3 decreased the survival of patients and were correlated with tobacco use and less differentiated tumors. Tese (Doutorado)

The aim of this study was to develop a novel method to detect circulating histones H3 and H2B in plasma based on multiple reaction monitoring targeted mass spectrometry and a multiple reaction monitoring approach (MRM-MS) for its clinical application in critical bacteriaemic septic shock patients. Plasma samples from 17 septic shock patients with confirmed bacteraemia and 10 healthy controls were analysed by an MRM-MS method, which specifically detects presence of histones H3 and H2B. By an internal standard, it was possible to quantify the concentration of circulating histones in plasma, which were significantly higher in patients, and thus confirmed their potential as biomarkers for diagnosing septic shock. After comparing surviving patients and non-survivors, a correlation was found between higher levels of circulating histones and unfavourable outcome. Indeed, histone H3 proved a more efficient and sensitive biomarker for septic shock prognosis. In conclusion, these findings suggest the accuracy of the MRM-MS technique and stable isotope labelled peptides to detect and quantify circulating plasma histones H2B and H3. This method may be used for early septic shock diagnoses and for the prognosis of fatal outcomes. Sin financiación 4.122 JCR (2017) Q1, 12/64 Multidisciplinary Sciences UEV

Background: Nucleosomes are the building blocks of chromatin where gene regulation takes place. Chromatin landscapes have been profiled for several species, providing insights into the fundamental mechanisms of chromatin-mediated transcriptional regulation of gene expression. However, knowledge is missing for several major and deep-branching eukaryotic groups, such as the Stramenopiles, which include the diatoms. Diatoms are highly diverse and ubiquitous species of phytoplankton that play a key role in global biogeochemical cycles. Dissecting chromatin-mediated regulation of genes in diatoms will help understand the ecological success of these organisms in contemporary oceans. Results: Here, we use high resolution mass spectrometry to identify a full repertoire of post-translational modifications on histones of the marine diatom Phaeodactylum tricornutum, including eight novel modifications. We map five histone marks coupled with expression data and show that P. tricornutum displays both unique and broadly conserved chromatin features, reflecting the chimeric nature of its genome. Combinatorial analysis of histone marks and DNA methylation demonstrates the presence of an epigenetic code defining activating or repressive chromatin states. We further profile three specific histone marks under conditions of nitrate depletion and show that the histone code is dynamic and targets specific sets of genes. Conclusions: This study is the first genome-wide characterization of the histone code from a stramenopile and a marine phytoplankton. The work represents an important initial step for understanding the evolutionary history of chromatin and how epigenetic modifications affect gene expression in response to environmental cues in marine environments. Instituto de Biotecnología Fil: Veluchamy, Alaguraj. Centre National de la Recherche Scientifique. Institut de Biologie de l’École Normale Supérieure. Ecology and Evolutionary Biology Section; Francia. King Abdullah University of Science and Technology. BESE Division. Center for Desert Agriculture; Arabia Saudita Fil: Rastogi, Achal. Centre National de la Recherche Scientifique. Institut de Biologie de l’École Normale Supérieure. Ecology and Evolutionary Biology Section; Francia Fil: Lin, Xin. Centre National de la Recherche Scientifique. Institut de Biologie de l’École Normale Supérieure. Ecology and Evolutionary Biology Section; Francia. Xiamen University. State key lab of Marine Environmental Science; China Fil: Lombard, Bérangère. Institut Curie PSL Research University. Centre de Recherche. Laboratoire de Spectrométrie de Masse Protéomique; Francia Fil: Murik, Omer. Centre National de la Recherche Scientifique. Institut de Biologie de l’École Normale Supérieure. Ecology and Evolutionary Biology Section; Francia Fil: Thomas, Yann. Centre National de la Recherche Scientifique. Institut de Biologie de l’École Normale Supérieure. Ecology and Evolutionary Biology Section; Francia Fil: Dingli, Florent. Institut Curie PSL Research University. Centre de Recherche. Laboratoire de Spectrométrie de Masse Protéomique; Francia Fil: Rivarola, Maximo Lisandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Biotecnología; Argentina. University of Maryland School of Medicine. Institute for Genome Sciences; Estados Unidos Fil: Ott, Sandra. University of Maryland School of Medicine. Institute for Genome Sciences; Estados Unidos Fil: Liu, Xinyue. University of Maryland School of Medicine. Institute for Genome Sciences; Estados Unidos Fil: Sun, Yezhou. University of Maryland School of Medicine. Institute for Genome Sciences; Estados Unidos Fil: Rabinowicz, Pablo D. University of Maryland School of Medicine. Institute for Genome Sciences; Estados Unidos Fil: McCarthy, James. J. Craig Venter Institute; Estados Unidos Fil: Allen, Andrew E. J. Craig Venter Institute; Estados Unidos. University of California. Integrative Oceanography Division. Scripps Institution of Oceanography; Estados Unidos Fil: Loew, Damarys. Institut Curie PSL Research University. Centre de Recherche. Laboratoire de Spectrométrie de Masse Protéomique; Francia Fil: Bowler, Chris. Centre National de la Recherche Scientifique. Institut de Biologie de l’École Normale Supérieure. Ecology and Evolutionary Biology Section; Francia Fil: Tirichine, Leïla. Centre National de la Recherche Scientifique. Institut de Biologie de l’École Normale Supérieure. Ecology and Evolutionary Biology Section; Francia

La Epigenética se refiere a los cambios heredables en el ADN e histonas que no implican altera ciones en la secuencia de nucleótidos y modifican la estructura y condensación de la cromatina por lo que afectan la expresión génica y el fenotipo. Las modificaciones epigenéticas son metilación del ADN y modificaciones de histonas. Objetivo: hacer una revisión de la literatura sobre e concepto de epigenética y su impacto en la salud. Materiales y métodos: se realizó una revisión de la bibliografía sobre el concepto de epigenética, sus bases biológicas, el impacto sobre la salud y la enfermedad y su relación con la evolución. Resultados: los mecanismos epigenéticos ha cobrado cada vez más importancia debido a la creciente asociación con enfermedades compleja y comunes, así como por su impacto en la salud de generaciones futuras y en la evolución humana. Conclusiones: la Epigenética tiene un claro impacto en la salud del individuo, en la de su descendencia y en la evolución de la especie humana. Epigenetics refers to inheritable changes in DNA and histones that do not involve changes in the sequence of nucleotides and that modifies structure and chromatin condensation, thus affecting gene expression and phenotype. Epigenetic modifications are DNA methylation and histone modifications. Objective: A review of the literature on the concept of Epigenetics and its impact on health. Materials and methods: A review of the literature was performed on the concept of epigenetics, its biological basis, the impact on health and disease and its relation to evolution. Results: Epigenetic mechanisms have become increasingly important because of the growing association with common complex diseases as well as its impact on health of future generations and in human evolution. Conclusions: Epigenetics has a clear impact on the health of individuals in their offspring and with the evolution of the human species. A Epigenética refere-se às mudanças hereditárias no ADN e histonas que não implicam alterações nas sequencia de nucleotídeos e modificam a estrutura e condensação da cromatina, pelo que afetam a expressão gênica e o fenótipo. As modificações epigenéticas são metilação do ADN e modificações de histonas. Objetivo: fazer uma revisão da literatura sobre o conceito de epigenética e seu impacto na saúde. Materiais e métodos: realizou-se uma revisão da bibliografia sobre o conceito de epigenética, suas bases biológicas, o impacto sobre a saúde e a doença e sua relação com a evolução. Resultados: os mecanismos epigenéticos têm adquirido cada vez mais importância devido à crescente associação com doenças complexas e comunes, assim como por seu impacto na saúde de gerações futuras e na evolução humana. Conclusões: a Epigenética tem um impacto evidente na saúde do individuo, na sua descendência e na evolução da espécie humana.

Made available in DSpace on 2017-07-21T19:59:52Z (GMT). No. of bitstreams: 1 LeonardoGoll.pdf: 2578520 bytes, checksum: e4dc5f18aad72bd8d62d5803fed3c4ef (MD5) Previous issue date: 2012-02-29 Conselho Nacional de Desenvolvimento Científico e Tecnológico TheColeopterahave a large variationof the sex determinationsystem, being the Xypmechanism considered ancestorfor thisorder. The presenceof a argyrophilous material associated with thesexbivalent is described asresponsible formaintenance andassociation of thesechromosomes.However,there is no consensus in the literature about the nature ofthisargyrophilous material. In addition,few species have been studied using fluorescence in situhybridization (FISH) tothe location of the multigene families, which areuseful and can elucidate the variation in the karyotype and genomic organization of several species.To date,there is no cytogenetic analysis in the genus Lagria.Thus, theaim of this study was tocharacterizecytogeneticallyLagriavillosa, throughconventional andmolecularcytogenetics, forinvestigating the mechanism ofassociationofsex chromosomesXyp,through analysis of nature of argyrophilous material in the lumen of sex bivalent. Additionally, thechromosomalmapping of 5S rDNA multigene families, 18S rDNA and histone H3 genes in L. villosa, was carried out, and showing for the first timein Coleoptera, that genes 18S and 5S DNAs are interspersed. In addition, the analysis oftesticular cellsshowed 2n=18=16+Xypand formulameiotic 2n=8II+Xyp.In this workwe discuss thepossible mechanismsevolvingin the association ofXypsex chromosomes,where it is consideredthat the combination ofsynaptonemalcomplex proteinsmayparticipate in thecorrect segregationofchromosomes.In addition, the fiber-FISH technique with dual probes (18S and 5S) was used for better resolution mapping of these regions in L. villosa, showing that the two DNAs are closely interspersed with varying amounts of both classes of DNA. Association between the two rDNA families have been reported for other species and different hypotheses are raised about the functional organization in these families. Os Coleoptera apresentam grande variação quanto aos sistemas de determinação sexual, sendo o mecanismo cromossômico do tipo Xyp considerado ancestral para esta ordem. A presença de uma substância argirofílica associada ao bivalente sexual é descrita como sendo a responsável pela manutenção e associação desses cromossomos, porém não existe um consenso na literatura sobre a natureza desse material. Além disso, poucas espécies têm sido analisadas utilizando a Hibridação in situ Fluorescente (FISH) para a localização das famílias multigênicas, as quaissão úteis marcadores e podem elucidar a variação do cariótipo e a organização genômica de diversas espécies.Até o presente momento, não existe análise citogenética em espécies do gênero Lagria. Desta forma, o objetivo desse trabalho foi caracterizar citogeneticamente Lagria villosa, através da citogenética convencional e molecular, investigando o mecanismo de associação dos cromossomos sexuais Xyp, através da análise da natureza do material argirofílico presente no lúmen do bivalente sexual. Adicionalmente, realizou-se o mapeamento cromossômico das famílias multigênicasDNAr 5S, DNAr18S e genes de histona H3 em L. villosa, mostrando pela primeira vez uma associação intercalar dosgenes DNAs 5S e 18S em Coleoptera. Além disso, aanálise de células testiculares evidenciou 2n=18=16+Xype fórmula meiótica 2n=8II+Xyp.No presente trabalho são discutidos os possíveis mecanismos evolvidos na associação dos cromossomos sexuais Xyp, onde é considerado que a associação de proteínas do complexo sinaptonêmico pode participar da correta segregação desses cromossomos. Além disso, atécnica de fiber-FISH com dupla sonda (18S e 5S) foi utilizada para uma melhor resolução do mapeamento dessas regiões genômicas em L. villosa, mostrando que os dois DNAs estão intimamente intercalados com quantidades variáveis de ambas as classes de DNA. Associação entre as duas famílias DNArtem sido relatadopara outras espécies e diferentes hipóteses são levantadas sobre a organização funcional dessas famílias.

La Epigenética se refiere a los cambios heredables en el ADN e histonas que no implican alteraciones en la secuencia de nucleótidos y modifican la estructura y condensación de la cromatina, por lo que afectan la expresión génica y el fenotipo. Las modificaciones epigenéticas son metilación del ADN y modificaciones de histonas. Objetivo: hacer una revisión de la literatura sobre el concepto de epigenética y su impacto en la salud. Materiales y métodos: se realizó una revisión de la bibliografía sobre el concepto de epigenética, sus bases biológicas, el impacto sobre la salud y la enfermedad y su relación con la evolución. Resultados: los mecanismos epigenéticos han cobrado cada vez más importancia debido a la creciente asociación con enfermedades complejas y comunes, así como por su impacto en la salud de generaciones futuras y en la evolución humana. Conclusiones: la Epigenética tiene un claro impacto en la salud del individuo, en la de su descendencia y en la evolución de la especie humana. Epigenetics refers to inheritable changes in DNA and histones that do not involve changes in the sequence of nucleotides and that modifies structure and chromatin condensation, thus affecting gene expression and phenotype. Epigenetic modifications are DNA methylation and histone modifications. Objective: A review of the literature on the concept of Epigenetics and its impact on health. Materials and methods: A review of the literature was performed on the concept of epigenetics, its biological basis, the impact on health and disease and its relation to evolution. Results: Epigenetic mechanisms have become increasingly important because of the growing association with common complex diseases as well as its impact on health of future generations and in human evolution. Conclusions: Epigenetics has a clear impact on the health of individuals in their offspring and with the evolution of the human species A Epigenética refere-se às mudanças hereditárias no ADN e histonas que não implicam alterações nas sequencia de nucleotídeos e modificam a estrutura e condensação da cromatina, pelo que afetam a expressão gênica e o fenótipo. As modificações epigenéticas são metilação do ADN e modificações de histonas. Objetivo: fazer uma revisão da literatura sobre o conceito de epigenética e seu impacto na saúde. Materiais e métodos: realizou-se uma revisão da bibliografia sobre o conceito de epigenética, suas bases biológicas, o impacto sobre a saúde e a doença e sua relação com a evolução. Resultados: os mecanismos epigenéticos têm adquirido cada vez mais importância devido à crescente associação com doenças complexas e comunes, assim como por seu impacto na saúde de gerações futuras e na evolução humana. Conclusões: a Epigenética tem um impacto evidente na saúde do individuo, na sua descendência e na evolução da espécie humana.

Introdução: O Adenocarcinoma ductal pancreático é um tumor bastante agressivo que apresenta uma alta de letalidade e, para o qual, poucas opções terapêuticas estão disponíveis. Isto pode ser parcialmente explicado pela complexidade derivada de múltiplas aberrações genéticas e da população celular mista presente em um tumor pancreático, o que também pode explicar o curso clínico heterogêneo observado na prática diária. Ultimamente, pesquisas científicas têm contribuído para ampliar o conhecimento sobre o impacto das alterações epigenéticas no desenvolvimento de múltiplos tipos de câncer, porém no pâncreas essas alterações ainda são incertas e, por isso, foco de investigação. A desregulação epigenética parece estar envolvida no ciclo celular da célula tumoral, incluindo o crescimento celular, diferenciação, progressão tumoral e morte celular, e a acetilação das histonas é um importante mecanismo que regula a transcrição de genes envolvidos nesses processos. Padrões globais de modificações das histonas foram recentemente apontados como preditores de desfecho em pacientes com câncer, mas poucos estudos têm sido realizados nesta área, inclusive em Adenocarcinoma ductal pancreático (ADP). Objetivos: O presente estudo foi desenvolvido a fim de investigar o padrão de modificação de acetilação das histonas em adenocarcinoma pancreático, através da análise imunohistoquímica. Materiais e métodos: Uma análise clinicopatológica retrospectiva foi realizada em 119 pacientes diagnosticados com câncer de pâncreas entre os anos de 2005 e 2011, e realizado estudo imunohistoquímico com os anticorpos contra H4K12ac, H3K9ac e H3K18ac. Marcação nuclear positiva para cada histona foi medida quanto à intensidade e expressão, sendo classificadas em grupos de baixa ou de alta intensidade/expressão. Os resultados foram analisados em relação aos parâmetros clinicopatológicos de cada paciente. Resultados: Houve uma relação positiva entre diferenciação tumoral e alta expressão de H4K12ac (P

Freezing temperatures are one of the environmental stresses with more impact in plant development in temperate regions. By means of cold acclimation, many plant species are able to increase their freezing tolerance in response to low-nonfreezing temperatures. In the last years, an important effort has been made to characterize the molecular mechanisms that control this adaptive process. Transcriptome analyses indicate that cold acclimation is mainly regulated by low temperatures through changes in gene expression. In this regard, it has been reported that 3.4% of Arabidopsis genes are regulated by low temperature, including 95 genes annotated as transcription factors. The control of coldinducible gene expression is very complex and involves many different signaling pathways that, in some cases, seem to share common intermediates. Interestingly, recent reports have shown that RNA processing and export, as well as post-translational modifications, including ubiquitylation and SUMOylation, also play important roles in regulating cold acclimation. Furthermore, histone modifications seem to be relevant in this regulation. In fact, histone acetylation and deacetylation are needed for correct activation of gene expression in response to low temperatures. All these data reveal that post-transcriptional mechanisms should be taken into consideration when analyzing the control of cold acclimation. Following, is a brief overview of the current understanding on the regulatory mechanisms that ensures the accurate development of this adaptive response. Las temperaturas de congelación son uno de los estreses ambientales con mayor impacto en el desarrollo de las plantas en las regiones templadas. Por medio de la respuesta de aclimatación, muchas especies son capaces de incrementar su tolerancia a la congelación en respuesta a temperaturas bajas propiamente dichas. En los últimos años, se ha realizado un gran esfuerzo en la caracterización de los mecanismos moleculares que controlan este proceso adaptativo. Análisis transcriptómicos indican que la aclimatación al frío es regulada principalmente por cambios en la expresión génica. En este sentido, se ha descrito que la expresión de un 3,4% de los genes de Arabidopsis está regulada por las temperaturas bajas, incluyendo 95 genes anotados como factores de transcripción. El control de la expresión génica inducible por frío es muy complejo e implica diferentes rutas de señalización de la señal que, en algunos casos, parecen compartir intermediarios comunes. Trabajos recientes han mostrado que el procesamiento y movilización de RNA, y algunas modificaciones post-traduccionales de proteínas como la ubiquitinación y la SUMOilización también juegan un papel importante en la regulación del proceso de aclimatación a las temperaturas bajas. Más aún, la modificación de histonas parece ser también relevante en esta regulación. De hecho, la acetilación y deacetilación de histonas es necesaria para una correcta activación de la expresión génica en respuesta a las temperaturas bajas. Todos estos datos ponen de manifiesto que a la hora de estudiar el control de proceso de aclimatación se han de tener en cuenta los mecanismos de regulación post-transcripcional. A continuación, repasaremos los conocimientos actuales sobre los mecanismos que aseguran el correcto desarrollo de esta respuesta adaptativa.

Journal Article; Research Support, Non-U.S. Gov't; The transcription factor Aiolos (also known as IKZF3), a member of the Ikaros family of zinc-finger proteins, plays an important role in the control of B lymphocyte differentiation and proliferation. Previously, multiple isoforms of Ikaros family members arising from differential splicing have been described and we now report a number of novel isoforms of Aiolos. It has been demonstrated that full-length Ikaros family isoforms localize to heterochromatin and that they can associate with complexes containing histone deacetylase (HDAC). In this study, for the first time we directly investigate the cellular localization of various Aiolos isoforms, their ability to heterodimerize with Ikaros and associate with HDAC-containing complexes, and the effects on histone modification and binding to putative targets. Our work demonstrates that the cellular activities of Aiolos isoforms are dependent on combinations of various functional domains arising from the differential splicing of mRNA transcripts. These data support the general principle that the function of an individual protein is modulated through alternative splicing, and highlight a number of potential implications for Aiolos in normal and aberrant lymphocyte function. Yes