Hung T J, Kemphues K J
Section of Genetics and Development, Cornell University, Ithaca, NY 14853, USA.
Development. 1999 Jan;126(1):127-35. doi: 10.1242/dev.126.1.127.
The par genes are required to establish polarity in the Caenorhabditis elegans embryo. Mutations in two of these genes, par-3 and par-6, exhibit similar phenotypes. A third gene, pkc-3, gives a similar phenotype when the protein is depleted by RNA interference. PAR-3 and PKC-3 protein are colocalized to the anterior periphery of asymmetrically dividing cells of the germline lineage and the peripheral localizations of both proteins depends upon the activity of par-6. Here we report the molecular cloning of par-6 and the immunolocalization of PAR-6 protein. We found that par-6 encodes a PDZ-domain-containing protein and has homologues in mammals and flies. Moreover, we discovered that PAR-6 colocalizes with PAR-3 and that par-3 and pkc-3 activity are required for the peripheral localization of PAR-6. The localization of both PAR-3 and PAR-6 proteins is affected identically by mutations in the par-2, par-4 and par-5 genes. The co-dependence of PAR-3, PAR-6 and PKC-3 for peripheral localization and the overlap in their distributions lead us to propose that they act in a protein complex.
par基因对于秀丽隐杆线虫胚胎极性的建立是必需的。其中两个基因par-3和par-6发生突变时表现出相似的表型。当通过RNA干扰使第三个基因pkc-3的蛋白质耗竭时，也会出现相似的表型。PAR-3和PKC-3蛋白共定位于生殖系谱系不对称分裂细胞的前周边，并且这两种蛋白的周边定位均依赖于par-6的活性。在此我们报告par-6的分子克隆及PAR-6蛋白的免疫定位。我们发现par-6编码一种含PDZ结构域的蛋白，并且在哺乳动物和果蝇中存在同源物。此外，我们发现PAR-6与PAR-3共定位，并且PAR-6的周边定位需要par-3和pkc-3的活性。PAR-3和PAR-6蛋白的定位受par-2、par-4和par-5基因突变的影响相同。PAR-3、PAR-6和PKC-3在周边定位上的相互依赖性以及它们分布的重叠使我们推测它们在一个蛋白复合物中发挥作用。
