Burns Kathleen H, Viveiros Maria M, Ren Yongsheng, Wang Pei, DeMayo Francesco J, Frail Donald E, Eppig John J, Matzuk Martin M
Department of Pathology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
Science. 2003 Apr 25;300(5619):633-6. doi: 10.1126/science.1081813.
Upon fertilization, remodeling of condensed maternal and paternal gamete DNA occurs to form the diploid genome. In Xenopus laevis, nucleoplasmin 2 (NPM2) decondenses sperm DNA in vitro. To study chromatin remodeling in vivo, we isolated mammalian NPM2 orthologs. Mouse NPM2 accumulates in oocyte nuclei and persists in preimplantation embryos. Npm2 knockout females have fertility defects owing to failed preimplantation embryo development. Although sperm DNA decondensation proceeds without NPM2, abnormalities are evident in oocyte and early embryonic nuclei. These defects include an absence of coalesced nucleolar structures and loss of heterochromatin and deacetylated histone H3 that normally circumscribe nucleoli in oocytes and early embryos, respectively. Thus, Npm2 is a maternal effect gene critical for nuclear and nucleolar organization and embryonic development.
受精时，浓缩的母本和父本配子DNA会发生重塑以形成二倍体基因组。在非洲爪蟾中，核质蛋白2（NPM2）可在体外使精子DNA解聚。为了研究体内的染色质重塑，我们分离了哺乳动物的NPM2直系同源物。小鼠NPM2在卵母细胞核中积累，并在植入前胚胎中持续存在。Npm2基因敲除的雌性由于植入前胚胎发育失败而存在生育缺陷。尽管精子DNA的解聚在没有NPM2的情况下仍可进行，但在卵母细胞和早期胚胎细胞核中仍明显存在异常。这些缺陷包括缺乏融合的核仁结构，以及分别在卵母细胞和早期胚胎中通常围绕核仁的异染色质和去乙酰化组蛋白H3的丢失。因此，Npm2是一个对核与核仁组织及胚胎发育至关重要的母体效应基因。
