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    宋晓元

    • 教授 博士生导师 硕士生导师
    • 教师英文名称:Xiaoyuan Song
    • 教师拼音名称:songxiaoyuan
    • 电子邮箱:
    • 学历:博士研究生毕业
    • 办公地点:中国科学技术大学西校区科技东楼915
    • 学位:博士
    • 毕业院校:美国罗彻斯特大学
    • 学科:生物学
    • 2022-10-01曾获荣誉当选:“典赞 2022科普安徽”科普活动“年度科普作品”
    • 2021-05-01曾获荣誉当选:安徽省优秀科普作品一等奖
    • 2019-09-16曾获荣誉当选:王宽诚育才奖

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    Phosphorylation of the SQ H2A.X motif is required for proper meiosis and mitosis in Tetrahymena thermophila

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    DOI码:10.1128/MCB.01910-06

    发表刊物:Mol Cell Biol

    摘要:Phosphorylation of the C terminus SQ motif that defines H2A.X variants is required for efficient DNA double-strand break (DSB) repair in diverse organisms but has not been studied in ciliated protozoa. Tetrahymena H2A.X is one of two similarly expressed major H2As, thereby differing both from mammals, where H2A.X is a quantitatively minor component, and from Saccharomyces cerevisiae where it is the only type of major H2A. Tetrahymena H2A.X is phosphorylated in the SQ motif in both the mitotic micronucleus and the amitotic macronucleus in response to DSBs induced by chemical agents and in the micronucleus during prophase of meiosis, which occurs in the absence of a synaptonemal complex. H2A.X is phosphorylated when programmed DNA rearrangements occur in developing macronuclei, as for immunoglobulin gene rearrangements in mammals, but not during the DNA fragmentation that accompanies breakdown of the parental macronucleus during conjugation, correcting the previous interpretation that this process is apoptosis-like. Using strains containing a mutated (S134A) SQ motif, we demonstrate that phosphorylation of this motif is important for Tetrahymena cells to recover from exogenous DNA damage and is required for normal micronuclear meiosis and mitosis and, to a lesser extent, for normal amitotic macronuclear division; its absence, while not lethal, leads to the accumulation of DSBs in both micro- and macronuclei. These results demonstrate multiple roles of H2A.X phosphorylation in maintaining genomic integrity in different phases of the Tetrahymena life cycle.

    卷号:27

    期号:7

    页面范围:2648-60

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