Hardin Jeff, King Ryan, Thomas-Virnig Christina, Raich William B
Department of Zoology, University of Wisconsin, Madison, Wisconsin 53706, USA.
Dev Dyn. 2008 Mar;237(3):830-6. doi: 10.1002/dvdy.21455.
ZEN-4/MKLP1 is required maternally for cytokinesis in Caenorhabditis elegans, but was originally identified in a screen for zygotic lethal, enclosure abnormal (Zen) mutants. We report that zen-4(w35) homozygotes exhibit stochastic failures in cytokinesis in multiple lineages. Remarkably, multinucleate epidermal cells show directional migration, even when there are as few as half the normal number of cells. Temperature shift experiments and analysis of zen-4::gfp expression confirm that the epidermal requirement for zen-4 function precedes morphogenesis. Driving expression of wild-type zen-4 by means of an epithelial-specific transgene can rescue many epidermal morphogenetic defects in zen-4 mutants. Early expression of unc-119 in epidermal precursors made this promoter unsuitable as a neuronal-specific driver in this context. Our results indicate that zygotic zen-4 function is required for correct division of epidermal precursors and, hence, indirectly for normal morphogenesis and that the epidermal morphogenetic program is surprisingly robust even in the absence of zen-4 function.
在秀丽隐杆线虫中，ZEN-4/MKLP1在胞质分裂过程中是母系必需的，但最初是在对合子致死、包被异常（Zen）突变体的筛选中被鉴定出来的。我们报告称，zen-4（w35）纯合子在多个谱系的胞质分裂中表现出随机失败。值得注意的是，多核表皮细胞即使在细胞数量只有正常数量一半的情况下也会表现出定向迁移。温度转换实验和对zen-4::gfp表达的分析证实，表皮对zen-4功能的需求先于形态发生。通过上皮特异性转基因驱动野生型zen-4的表达可以挽救zen-4突变体中的许多表皮形态发生缺陷。在表皮前体中早期表达unc-119使得该启动子在这种情况下不适宜作为神经元特异性驱动子。我们的结果表明，合子zen-4功能对于表皮前体的正确分裂是必需的，因此间接对于正常形态发生也是必需的，并且即使在没有zen-4功能的情况下，表皮形态发生程序也出奇地稳健。
