Tabara H, Hill R J, Mello C C, Priess J R, Kohara Y
Department of Genetics, Graduate University of Advanced Studies and Gene Network Lab, National Institute of Genetics, Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Mishima 411, Japan.
Development. 1999 Jan;126(1):1-11. doi: 10.1242/dev.126.1.1.
Germ cells arise during early C. elegans embryogenesis from an invariant sequence of asymmetric divisions that separate germ cell precursors from somatic precursors. We show that maternal-effect lethal mutations in the gene pos-1 cause germ cell precursors to inappropriately adopt somatic cell fates. During early embryogenesis, pos-1 mRNA and POS-1 protein are present predominantly in the germ precursors. POS-1 is a novel protein with two copies of a CCCH finger motif previously described in the germline proteins PIE-1 and MEX-1 in C. elegans, and in the mammalian TIS11/Nup475/TTP protein. However, mutations in pos-1 cause several defects in the development of the germline blastomeres that are distinct from those caused by mutations in pie-1 or mex-1. The earliest defect detected in pos-1 mutants is the failure to express APX-1 protein from maternally provided apx-1 mRNA, suggesting that POS-1 may have an important role in regulating the expression of maternal mRNAs in germline blastomeres.
生殖细胞在秀丽隐杆线虫胚胎发育早期由一系列不对称分裂产生，这些分裂将生殖细胞前体与体细胞前体分离。我们发现，基因pos-1中的母源效应致死突变会导致生殖细胞前体不恰当地分化为体细胞命运。在胚胎发育早期，pos-1 mRNA和POS-1蛋白主要存在于生殖前体中。POS-1是一种新型蛋白质，具有两个CCCH锌指基序，此前在秀丽隐杆线虫的生殖系蛋白PIE-1和MEX-1以及哺乳动物的TIS11/Nup475/TTP蛋白中也有描述。然而，pos-1突变会导致生殖系卵裂球发育出现一些缺陷，这些缺陷与pie-1或mex-1突变引起的缺陷不同。在pos-1突变体中检测到的最早缺陷是无法从母源提供的apx-1 mRNA中表达APX-1蛋白，这表明POS-1可能在调节生殖系卵裂球中母源mRNA的表达方面发挥重要作用。
