Kadyk L C, Lambie E J, Kimble J
Howard Hughes Medical Institute, Laboratory of Molecular Biology, University of Wisconsin-Madison 53706, USA.
Genetics. 1997 Jan;145(1):111-21. doi: 10.1093/genetics/145.1.111.
The germ line is the only tissue in Caenorhabditis elegans in which a stem cell population continues to divide mitotically throughout life; hence the cell cycles of the germ line and the soma are regulated differently. Here we report the genetic and phenotypic characterization of the glp-3 gene. In animals homozygous for each of five recessive loss-of-function alleles, germ cells in both hermaphrodites and males fail to progress through mitosis and meiosis, but somatic cells appear to divide normally. Germ cells in animals grown at 15 degrees appear by DAP1 staining to be uniformly arrested at the G2/M transition with < 20 germ cells per gonad on average, suggesting a checkpoint-mediated arrest. In contrast, germ cells in mutant animals grown at 25 degrees frequently proliferate slowly during adulthood, eventually forming small germ lines with several hundred germ cells. Nevertheless, cells in these small germ lines never undergo meiosis. Double mutant analysis with mutations in other genes affecting germ cell proliferation supports the idea that glp-3 may encode a gene product that is required for the mitotic and meiotic cell cycles in the C. elegans germ line.
生殖系是秀丽隐杆线虫中唯一一种干细胞群体在整个生命过程中持续进行有丝分裂的组织；因此，生殖系和体细胞的细胞周期受到不同的调控。在此，我们报告了glp-3基因的遗传和表型特征。在五个隐性功能丧失等位基因中每个基因的纯合动物中，雌雄同体和雄性的生殖细胞都无法完成有丝分裂和减数分裂，但体细胞似乎能正常分裂。在15摄氏度下生长的动物的生殖细胞，通过DAP1染色显示平均每个性腺中不到20个生殖细胞，它们在G2/M期均一性停滞，提示这是一种由检查点介导的停滞。相比之下，在25摄氏度下生长的突变动物的生殖细胞在成年期经常增殖缓慢，最终形成含有数百个生殖细胞的小生殖系。然而，这些小生殖系中的细胞从未进行减数分裂。与影响生殖细胞增殖的其他基因突变进行双突变分析支持了这样一种观点，即glp-3可能编码一种秀丽隐杆线虫生殖系中有丝分裂和减数分裂细胞周期所需的基因产物。
