生物谷:生殖细胞中的染色体异常,会引发新生婴儿的许多疾病,包括不孕症(infertility)、流产(miscarriage)、染色体数目不规则(非整倍体;aneuploidy),等等。一项来自卡罗林斯卡研究所(Karolinska Institute)的新的研究报告向我们展示了,生殖细胞形成的时候,染色体紊乱的发生机制。
生殖细胞中通常有一套“控制站”(control station),用于监测 一个确保正确分配染色体到子细胞的机制。科学家发现,在雌性生殖细胞中还存在另外一套分配机制,这套机制会引起染色体紊乱。变异的染色体可以将它们自身 “装扮”成正常的染色体,这种拥有两种身份的本领让它们躲避了控制站的监测。
“我们相信这个根本的机制,可以用于解释为何磁性生殖细胞中更容易发生染色体紊乱,”研究的主持者Christer Höög教授介绍说。此项研究可能最终有助于医疗技术的研发,从而降低胎儿畸形的概率。
超过0.3%的儿童都患有一定程度的染色体紊乱。当中绝大多数患有唐氏综合症(Downs Syndrome),或因为获得错误数量的性染色体而患有特纳综合征(Turner’s syndrome)或克兰费尔特氏综合症(Klinefelter’s syndrome)。唐氏综合症只发生在女性当中,是因为两条X染色体中缺失了一条引起的。患有特纳综合征的女孩会停滞发育,如果没有接受合适的治疗的话,将不会进入青春期。克兰费尔特氏综合症是因为男性额外接受了一条X染色体引起的,症状有注意力不集中、运动技能差和不育等。(援引生命经纬)
图:Univalents in Sycp3-/- oocytes are bi-oriented in a mitotic manner and evade the SAC.
资料来源:Karolinska Institutet
原始出处:
Brief Communication abstract
Nature Genetics
Published online: 8 July 2007 | doi:10.1038/ng2065
Bi-orientation of achiasmatic chromosomes in meiosis I oocytes contributes to aneuploidy in mice
Anna Kouznetsova1, Lisa Lister2, Magnus Nordenskjöld3, Mary Herbert2 & Christer Höög1
Abstract
The spindle assembly checkpoint guards against chromosomal missegregation but does not induce arrest in oocytes that contain a few achiasmatic chromosomes (univalents). We followed the fate of univalents in oocytes during the first meiotic division, and although these preserved a meiotic kinetochore structure, they were also bi-oriented in a mitotic manner. The hybrid chromosomal configuration attained by univalents allows them to evade the spindle assembly checkpoint and contribute to aneuploidy in oocytes.
Department of Cell and Molecular Biology, Karolinska Institutet, S-171 77, Stockholm, Sweden.
Newcastle Fertility Centre, Institute of Human Genetics and North East England Stem Cell Institute, Newcastle University, Bioscience Building, International Centre for Life, Newcastle upon Tyne NE1 4EP, UK.
Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska University Hospital, 171 76 Solna, Sweden.
Correspondence to: Christer Höög1 e-mail: christer.hoog@ki.se