Kemphues K J, Priess J R, Morton D G, Cheng N S
Section of Genetics and Development Cornell University Ithaca, New York 14853.
Cell. 1988 Feb 12;52(3):311-20. doi: 10.1016/s0092-8674(88)80024-2.
We have isolated and analyzed eight strict maternal effect mutations identifying four genes, par-1, par-2, par-3, and par-4, required for cytoplasmic localization in early embryos of the nematode C. elegans. Mutations in these genes lead to defects in cleavage patterns, timing of cleavages, and localization of germ line-specific P granules. Four mutations in par-1 and par-4 are fully expressed maternal effect lethal mutations; all embryos from mothers homozygous for these mutations arrest as amorphous masses of differentiated cells but are specifically lacking intestinal cells. Four mutations in par-2, par-3, and par-4 are incompletely expressed maternal effect lethal mutations and are also grandchildless; some embryos from homozygous mothers survive and grow to become infertile adults due to absence of functional germ cells. We propose that all of these defects result from the failure of a maternally encoded system for intracellular localization in early embryos.
我们已经分离并分析了八个严格的母体效应突变，鉴定出四个基因，即par-1、par-2、par-3和par-4，它们是秀丽隐杆线虫早期胚胎细胞质定位所必需的。这些基因的突变会导致卵裂模式、卵裂时间以及生殖系特异性P颗粒定位的缺陷。par-1和par-4中的四个突变是完全表达的母体效应致死突变；这些突变纯合母亲所产生的所有胚胎都会停滞为分化细胞的无定形团块，但特别缺乏肠道细胞。par-2、par-3和par-4中的四个突变是不完全表达的母体效应致死突变，并且也会导致无孙辈；纯合母亲所产生的一些胚胎能够存活并成长为不育的成虫，这是由于缺乏功能性生殖细胞所致。我们认为所有这些缺陷都是由于早期胚胎中一个由母体编码的细胞内定位系统失效所导致的。
