RESUMO
Robertsonian translocations are the most frequent chromosomal rearrangements detected in cattle. Here, we report on the detection of a new Robertsonian translocation between chromosomes BTA3 and BTA16. This rob(3;16) was dicentric, suggesting that its occurrence was recent. FISH analysis of decondensed sperm nuclei revealed a relatively low rate of unbalanced gametes produced by adjacent segregation (5.87%). In addition, and for the first time in bovines, a significant interchromosomal effect (ICE) was detected for 2 different autosomes: BTA17 (global disomy + nullisomy rate of 9%) and BTA20 (1.8%). These results suggest that ICE should be taken into consideration when assessing the putative effect of Robertsonian translocations on reproduction.
Assuntos
Segregação de Cromossomos , Cromossomos de Mamíferos/genética , Translocação Genética , Animais , Bovinos , Análise Citogenética/veterinária , Hibridização in Situ Fluorescente/veterinária , Masculino , Meiose , Espermatozoides/fisiologiaRESUMO
Conventional rabbit embryonic stem cell (ESC) lines are derived from the inner cell mass (ICM) of pre-implantation embryos using methods and culture conditions that are established for primate ESCs. In this study, we explored the capacity of the rabbit ICM to give rise to ESC lines using conditions similar to those utilized to generate naive ESCs in mice. On single-cell dissociation and culture in fibroblast growth factor 2 (FGF2)-free, serum-supplemented medium, rabbit ICMs gave rise to ESC lines lacking the DNA-damage checkpoint in the G1 phase like mouse ESCs, and with a pluripotency gene expression profile closer to the rabbit ICM/epiblast profiles. These cell lines can be converted to FGF2-dependent ESCs after culture in conventional conditions. They can also colonize the rabbit pre-implantation embryo. These results indicate that rabbit epiblast cells can be coaxed toward different types of pluripotent stem cells and reveal the dynamics of pluripotent states in rabbit ESCs.
Assuntos
Diferenciação Celular , Células-Tronco Embrionárias/citologia , Células-Tronco Embrionárias/metabolismo , Animais , Biomarcadores , Blastocisto/citologia , Blastocisto/metabolismo , Técnicas de Cultura de Células , Ciclo Celular , Diferenciação Celular/genética , Linhagem Celular , Autorrenovação Celular/genética , Células Cultivadas , Biologia Computacional/métodos , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Janus Quinases/metabolismo , Fator Inibidor de Leucemia/metabolismo , MicroRNAs/genética , Coelhos , Transdução de Sinais , TranscriptomaRESUMO
Individuals carrying balanced constitutional reciprocal translocations generally have a normal phenotype, but often present reproductive disorders. The aim of our research was to analyze the meiotic process in an oligoasthenoteratospermic boar carrying an asymmetric reciprocal translocation involving chromosomes 1 and 14. Different multivalent structures (quadrivalent and trivalent plus univalent) were identified during chromosome pairing analysis. Some of these multivalents were characterized by the presence of unpaired autosomal segments with histone γH2AX accumulation sometimes associated with the XY body. Gene expression in spermatocytes was studied by RNA-DNA-FISH and microarray-based testis transcriptome analysis. Our results revealed a decrease in gene expression for chromosomes 1 and 14 and an up-regulated expression of X-chromosome genes for the translocated boar compared with normal individuals. We hypothesized that the observed meiotic arrest and reproductive failure in this boar might be due to silencing of crucial autosomal genes (MSUC) and disturbance of meiotic sex chromosome inactivation (MSCI). Further analysis revealed abnormal meiotic recombination (frequency and distribution) and the production of a high rate of unbalanced spermatozoa.
