Jan 2008 Biochimie

Alternative ends: telomeres and meiosis.

Auteurs

de La Roche Saint-André C

Résumé

Meiosis is a specialized type of cell division that halves the diploid number of chromosomes, yielding four haploid nuclei. Dramatic changes in chromosomal organization occur within the nucleus at the beginning of meiosis which are followed by the separation of homologous chromosomes at the first meiotic division. This is the case for telomeres that display a meiotic-specific behavior with gathering in a limited sector of the nuclear periphery. This leads to a characteristic polarized chromosomal configuration, called the « bouquet » arrangement. The widespread phenomenon of bouquet formation among eukaryotes has led to the hypothesis that it is functionally linked to the process of interactions between homologous chromosomes that are a unique feature of meiosis and are essential for proper chromosome segregation. Various studies in different model organisms have questioned the role of the telomere bouquet in chromosome pairing and recombination, and very recently in meiotic spindle formation, and have provided some clues about the molecular mechanisms that carry out this specific clustering of telomeres.

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