Trinucleotide expansion in haploid germ cells by gap repair

摘要: Huntington disease (HD) is one of eight progressive neurodegenerative disorders in which the underlying mutation a CAG expansion encoding polyglutamine tract. The mechanism trinucleotide poorly understood. Expansion mediated by misaligned pairing repeats and inappropriate formation DNA secondary structure as duplex unpairs. It has never been clear, however, whether unpairing occurs during mitotic replication or strand-break repair. In simple organisms, arises slippage on either leading lagging strand, homologous recombination, gene conversion, double-strand break repair base excision repair; it not clear these mechanisms used mammalian cells vivo. We have followed heritable changes length male transgenic mice. germ cells, limited to post-meiotic, haploid cell therefore cannot involve recombination between chromosome sister chromatid. Our data support model gap depends complex containing Msh2. gap-filling synthesis when loops comprising are sealed into strand.