Base de dados : LILACS
Pesquisa : G04.144.220.220.687.444 [Categoria DeCS]
Referências encontradas : 4 [refinar]
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Texto completo SciELO Chile
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Id: biblio-950712
Autor: Berríos, Soledad; Manieu, Catalina; López-Fenner, Julio; Ayarza, Eliana; Page, Jesús; González, Marisel; Manterola, Marcia; Fernández-Donoso, Raúl.
Título: Robertsonian chromosomes and the nuclear architecture of mouse meiotic prophase spermatocytes
Fonte: Biol. Res;47:1-13, 2014. ilus, tab.
Idioma: en.
Resumo: BACKGROUND: The nuclear architecture of meiotic prophase spermatocytes is based on higher-order patterns of spatial associations among chromosomal domains from different bivalents. The meiotic nuclear architecture depends on the chromosome characteristics and consequently is prone to modification by chromosomal rearrangements. In this work, we consider Mus domesticus spermatocytes with diploid chromosome number 2n = 40, all telocentric, and investigate a possible modification of the ancestral nuclear architecture due to the emergence of derived Rb chromosomes, which may be present in the homozygous or heterozygous condition. RESULTS: In the 2n = 40 spermatocyte nuclei random associations mediated by pericentromeric heterochromatin among the 19 telocentric bivalents ocurr at the nuclear periphery. The observed frequency of associations among them, made distinguishable by specific probes and FISH, seems to be the same for pairs that may or may not form Rb chromosomes. In the homozygote Rb 2n = 24 spermatocytes, associations also mediated by pericentromeric heterochromatin occur mainly between the three telocentric or the eight metacentric bivalents themselves. In heterozygote Rb 2n = 32 spermatocytes all heterochromatin is localized at the nuclear periphery, yet associations are mainly observed among the three telocentric bivalents and between the asynaptic axes of the trivalents. CONCLUSIONS: The Rb chromosomes pose sharp restrictions for interactions in the 2n = 24 and 2n = 32 spermatocytes, as compared to the ample possibilities for interactions between bivalents in the 2n = 40 spermatocytes. Undoubtedly the emergence of Rb chromosomes changes the ancestral nuclear architecture of 2n = 40 spermatocytes since they establish new types of interactions among chromosomal domains, particularly through centromeric and heterochromatic regions at the nuclear periphery among telocentric and at the nuclear center among Rb metacentric ones.
Descritores: Espermatócitos/ultraestrutura
Núcleo Celular/genética
Cromossomos de Mamíferos/ultraestrutura
Prófase Meiótica I
-Frações Subcelulares
Heterocromatina
Sondas Moleculares
Núcleo Celular
Ultrassonografia
Hibridização in Situ Fluorescente
Estágio Paquíteno
Heterozigoto
Homozigoto
Limites: Animais
Masculino
Camundongos
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: CL1.1 - Biblioteca Central


  2 / 4 LILACS  
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Id: biblio-1038780
Autor: Berríos, Soledad; Fernández-Donoso, Raúl; Ayarza, Eliana.
Título: Synaptic configuration of quadrivalents and their association with the XY bivalent in spermatocytes of Robertsonian heterozygotes of Mus domesticus
Fonte: Biol. Res;50:38, 2017. tab, graf.
Idioma: en.
Projeto: Fondecyt.
Resumo: BACKGROUND: The nuclear architecture of meiotic prophase spermatocytes is based on higher-order patterns of spatial associations among chromosomal domains and consequently is prone to modification by chromosomal rearrangements. We have shown that nuclear architecture is modified in spermatocytes of Robertsonian (Rb) homozygotes of Mus domesticus. In this study we analyse the synaptic configuration of the quadrivalents formed in the meiotic pro- phase of spermatocytes of mice double heterozygotes for the dependent Rb chromosomes: Rbs 11.16 and 16.17. RESULTS: Electron microscope spreads of 60 pachytene spermatocytes from four animals of Mus domesticus 2n = 38 were studied and their respective quadrivalents analysed in detail. Normal synaptonemal complex was found between arms 16 of the Rb metacentric chromosomes, telocentrics 11 and 17 and homologous arms of the Rb metacentric chromosomes. About 43% of the quadrivalents formed a synaptonemal complex between the heterologous short arms of chromosomes 11 and 17. This synaptonemal complex is bound to the nuclear envelope through a fourth synapsed telomere, thus dragging the entire quadrivalent to the nuclear envelope. About 57% of quadrivalents showed unsynapsed single axes in the short arms of the telocentric chromosomes. About 90% of these unsynapsed quadrivalents also showed a telomere-to-telomere association between one of the single axes of the telocentric chromosome 11 or 17 and the X chromosome single axis, which was otherwise normally paired with the Y chromosome. Nucleolar material was associated with two bivalents and with the quadrivalent. CONCLUSIONS: The spermatocytes of heterozygotes for dependent Rb chromosomes formed a quadrivalent where four chromosomes are synapsed together and bound to the nuclear envelope through four telomeres. The nuclear configuration is determined by the fourth shortest telomere, which drags the centromere regions and heterochromatin of all the chromosomes towards the nuclear envelope, favouring the reiterated encounter and eventual rearrangement between the heterologous chromosomes. The unsynapsed regions of quadrivalents are frequently bound to the single axis of the X chromosome, possibly perturbing chromatin condensation and gene expression.
Descritores: Espermatócitos/fisiologia
Espermatócitos/ultraestrutura
Cromossomo X/fisiologia
Cromossomo Y/fisiologia
Complexo Sinaptonêmico/fisiologia
Nucléolo Celular/fisiologia
-Translocação Genética
Cromossomo X/genética
Cromossomo Y/genética
Complexo Sinaptonêmico/genética
Heterocromatina/fisiologia
Heterocromatina/genética
Nucléolo Celular/genética
Telômero/fisiologia
Telômero/genética
Prófase Meiótica I/fisiologia
Prófase Meiótica I/genética
Heterozigoto
Limites: Animais
Masculino
Camundongos
Responsável: CL1.1 - Biblioteca Central


  3 / 4 LILACS  
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Texto completo SciELO Saúde Pública
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Id: lil-744843
Autor: Bastos, Francisco I..
Título: Skill and art in an intolerant world: a brief commentary on the article by Paiva et al. / Engenho e arte em um mundo intolerante: breves comentários ao texto de Paiva et al. / Ingenio y arte en un mundo intolerante: breves comentarios al texto de Paiva et al.
Fonte: Cad. saúde pública = Rep. public health;31(3):1-2, 03/2015.
Idioma: en.
Descritores: Oócitos/citologia
Oócitos/fisiologia
Oogênese/fisiologia
Ovário/embriologia
/genética
TUMOR SUPPRESSOR PROTEIN PDIPETALONEMA INFECTIONS/genética
-Animais Recém-Nascidos
Apoptose/fisiologia
Fragmentação do DNA
Regulação da Expressão Gênica no Desenvolvimento
Marcação In Situ das Extremidades Cortadas
Camundongos Endogâmicos CBA
Camundongos Knockout
Prófase Meiótica I/fisiologia
MICE, INBRED CABDOMENABDOMINAL INJURIESBL
Proteínas Nucleares/metabolismo
Ovário/citologia
Ovário/fisiologia
Poli(ADP-Ribose) Polimerases/metabolismo
Limites: Animais
Feminino
Masculino
Camundongos
Gravidez
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


  4 / 4 LILACS  
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Id: lil-571988
Autor: Berríos, Soledad; Manterola, Marcia; Prieto, Zulita; López-Fenner, Julio; Page, Jesús; Fernández-Donoso, Raúl.
Título: Model of chromosome associations in Mus domesticus spermatocytes
Fonte: Biol. Res;43(3):275-285, 2010. ilus, graf, tab.
Idioma: en.
Projeto: FONDECYT; . Agencia Española de Cooperación Internacional para el Desarrollo (Spain).
Resumo: Understanding the spatial organization of the chromosomes in meiotic nuclei is crucial to our knowledge of the genome's functional regulation, stability and evolution. This study examined the nuclear architecture of Mus domesticus 2n=40 pachytene spermatocytes, analyzing the associations among autosomal bivalents via their Centromere Telomere Complexes (CTC). The study developed a nuclear model in which each CTC was represented as a 3D computer object. The probability of a given combination of associations among CTC was estimated by simulating a random distribution of 19 indistinguishable CTC over n indistinguishable "cells" on the nuclear envelope. The estimated association frequencies resulting from this numerical approach were similar to those obtained by quantifying actual associations in pachytene spermatocyte spreads. The nuclear localization and associations of CTC through the meiotic prophase in well-preserved nuclei were also analyzed. We concluded that throughout the meiotic prophase: 1) the CTC of autosomal bivalents are not randomly distributed in the nuclear space; 2) the CTC associate amongst themselves, probably at random, over a small surface of the nuclear envelope, at the beginning of the meiotic prophase; 3) the initial aggregation of centromere regions occurring in lepto-zygotene likely resolves into several smaller aggregates according to patterns of preferential partitioning; 4) these smaller aggregates spread over the inner face of the nuclear envelope, remaining stable until advanced stages of the meiotic prophase or even until the first meiotic division.
Descritores: Núcleo Celular/ultraestrutura
Cromossomos de Mamíferos/ultraestrutura
Espermatócitos/ultraestrutura
-Centrômero/ultraestrutura
Modelos Biológicos
Prófase Meiótica I/fisiologia
Membrana Nuclear/ultraestrutura
Telômero/ultraestrutura
Limites: Animais
Masculino
Camundongos
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: CL1.1 - Biblioteca Central



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