The C. elegans par-4 gene encodes a putative serine-threonine kinase required for establishing embryonic asymmetry.
The C. elegans par-4 gene encodes a putative serine-threonine kinase required for establishing embryonic asymmetry.
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发表时间：
2000-04
期刊：
影响因子：
4.6
通讯作者：
Jennifer L. Watts;D. Morton;Jennifer E. Bestman;K. Kemphues
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作者：
Jennifer L. Watts;D. Morton;Jennifer E. Bestman;K. Kemphues
在秀丽隐杆线虫胚胎发生的第一个细胞周期中，不对称性的建立对于决定子细胞随后的发育命运至关重要。母源表达的par基因是建立这种极性所必需的。一些par基因的产物本身在第一个细胞周期中是不对称分布的。我们已经鉴定了秀丽隐杆线虫的par-4基因，并发现它编码一种假定的丝氨酸-苏氨酸激酶，与Peutz-Jeghers综合征相关的人类激酶LKB1 （STK11）和非洲爪蟾卵和胚胎激酶XEEK1相似。一些强的par-4突变等位基因是错义突变，改变了激酶结构域内的保守残基，表明激酶活性对par-4功能至关重要。我们发现PAR-4蛋白存在于秀丽隐杆线虫的生殖腺、卵母细胞和早期胚胎中，并且在细胞质和皮质上都有分布。皮层分布开始于1细胞晚期，在2细胞和4细胞阶段更为明显，在胚胎发育晚期减少。我们发现PAR-4蛋白在秀丽隐杆线虫胚胎中的分布不对称。par -4蛋白在早期胚胎中的分布不受其他par基因突变的影响。
During the first cell cycle of Caenorhabditis elegans embryogenesis, asymmetries are established that are essential for determining the subsequent developmental fates of the daughter cells. The maternally expressed par genes are required for establishing this polarity. The products of several of the par genes have been found to be themselves asymmetrically distributed in the first cell cycle. We have identified the par-4 gene of C. elegans, and find that it encodes a putative serine-threonine kinase with similarity to a human kinase associated with Peutz-Jeghers Syndrome, LKB1 (STK11), and a Xenopus egg and embryo kinase, XEEK1. Several strong par-4 mutant alleles are missense mutations that alter conserved residues within the kinase domain, suggesting that kinase activity is essential for PAR-4 function. We find that the PAR-4 protein is present in the gonads, oocytes and early embryos of C. elegans, and is both cytoplasmically and cortically distributed. The cortical distribution begins at the late 1-cell stage, is more pronounced at the 2- and 4-cell stages and is reduced at late stages of embryonic development. We find no asymmetry in the distribution of PAR-4 protein in C. elegans embryos. The distribution of PAR-4 protein in early embryos is unaffected by mutations in the other par genes.