Publication: Caracterización de la función de la amenopeptidasa MPA1 en la meiosis de Arabidopsis Thaliana
Loading...
Official URL
Full text at PDC
Publication Date
2017
Authors
Advisors (or tutors)
Editors
Journal Title
Journal ISSN
Volume Title
Publisher
Citations
Exportar
Abstract
Las proteasas son enzimas esenciales para la regulación del ciclo celular, especialmente las aminopeptidasas. En el caso de Arabidopsis thaliana, especie modelo en genética vegetal, estas proteínas son mayoritariamente metaloenzimas y su función es el corte de enlaces peptídicos localizados en los extremos N-terminales, afectando a una región clave para las modificaciones postraduccionales. Las metalopeptidasas de la familia M1 se encuentran en todos los eucariotas y son imprescindibles para su correcto crecimiento y desarrollo. En plantas se ha descrito además su implicación en la división meiótica, la división celular especializada que conduce a la formación de los gametos. En A. thaliana, la ausencia de función de la aminopeptidasa MPA1 (MEIOTIC PROPHASE AMINOPEPTIDASE 1), metalopeptidasa sensible al antibiótico puromicina, produce problemas de fertilidad como consecuencia de la formación de un elevado porcentaje de granos de polen inviables. El análisis de la meiosis masculina en el mutante nulo mpa1-1 ha revelado deficiencias en la formación de los quiasmas, las conexiones debidas a intercambios recíprocos de ADN entre los cromosomas homólogos que permiten su correcta segregación en anafase I. En el presente estudio se han caracterizado diferentes alelos mutantes producidos por inserciones de T-DNA localizadas en distintas regiones del gen. Aunque no se han encontrado problemas de viabilidad de polen en las correspondientes líneas, la caracterización citológica de la meiosis ha puesto de manifiesto un descenso en la frecuencia media de quiasmas con respecto al genotipo silvestre. Los resultados obtenidos permiten profundizar en el análisis de la función de MPA1 en la meiosis de A. thaliana, para tratar de dilucidar su papel en el proceso de recombinación homóloga, responsable de la formación de los quiasmas.
Proteases are essential enzymes for the regulation of the cell cycle, especially aminopeptidases. In the model species for genetic studies Arabidopsis thaliana, most of them are metalloenzymes and their function is to cleave N-terminal peptide bonds, affecting a key region for post-translational modifications. M1 metalloproteases are present in all Eukaryotes and are indispensable for their correct growth and development. In plants, it has been reported their involvement in meiotic division, the specialised cellular division that leads to the gamete formation. In A. thaliana, the absence of the aminopeptidase MPA1 (MEIOTIC PROPHASE AMINOPEPTIDASE 1), a puromycin-sensitive metallopeptidase, produces fertility problems due to the formation of a high proportion of inviable pollen grains. The characterisation of the male meiosis in the knockout mutant mpa1-1 has revealed severe defects in chiasma formation, the connections produced between homologous chromosomes as consequence of reciprocal exchanges of DNA that are essential for their correct segregation at anaphase I. In the present study different mutant alleles, corresponding to several lines with T-DNA insertions located in different regions of the gene, have been characterised. Although inviable pollen grains have not been detected in these lines, the meiotic cytological characterization has revealed a decrease in the mean chiasma frequency respect to the wild type line. The results obtained allow a deeper analysis of the meiotic role of MPA1 in A. thaliana, in order to determine its implication during homologous recombination, the pathway responsible of chiasma formation.
Proteases are essential enzymes for the regulation of the cell cycle, especially aminopeptidases. In the model species for genetic studies Arabidopsis thaliana, most of them are metalloenzymes and their function is to cleave N-terminal peptide bonds, affecting a key region for post-translational modifications. M1 metalloproteases are present in all Eukaryotes and are indispensable for their correct growth and development. In plants, it has been reported their involvement in meiotic division, the specialised cellular division that leads to the gamete formation. In A. thaliana, the absence of the aminopeptidase MPA1 (MEIOTIC PROPHASE AMINOPEPTIDASE 1), a puromycin-sensitive metallopeptidase, produces fertility problems due to the formation of a high proportion of inviable pollen grains. The characterisation of the male meiosis in the knockout mutant mpa1-1 has revealed severe defects in chiasma formation, the connections produced between homologous chromosomes as consequence of reciprocal exchanges of DNA that are essential for their correct segregation at anaphase I. In the present study different mutant alleles, corresponding to several lines with T-DNA insertions located in different regions of the gene, have been characterised. Although inviable pollen grains have not been detected in these lines, the meiotic cytological characterization has revealed a decrease in the mean chiasma frequency respect to the wild type line. The results obtained allow a deeper analysis of the meiotic role of MPA1 in A. thaliana, in order to determine its implication during homologous recombination, the pathway responsible of chiasma formation.
Description
Grado en Biología, Mención de Biotecnología Curso 2016-2017