Plamann M, Minke P F, Tinsley J H, Bruno K S
Department of Biology, Texas A&M University, College Station 77843-3258.
J Cell Biol. 1994 Oct;127(1):139-149. doi: 10.1083/jcb.127.1.139.
Cytoplasmic dynein is a multisubunit, microtubule-dependent mechanochemical enzyme that has been proposed to function in a variety of intracellular movements, including minus-end-directed transport of organelles. Dynein-mediated vesicle transport is stimulated in vitro by addition of the Glued/dynactin complex raising the possibility that these two complexes interact in vivo. We report here that a class of phenotypically identical mutants of the filamentous fungus Neurospora crassa are defective in genes encoding subunits of either cytoplasmic dynein or the Glued/dynactin complex. These mutants, defined as ropy, have curled hyphae with abnormal nuclear distribution. ro-1 encodes the heavy chain of cytoplasmic dynein, while ro-4 encodes an actin-related protein that is a probable homologue of the actin-related protein Arpl (formerly referred to as actin-RPV or centractin), the major component of the glued/dynactin complex. The phenotypes of ro-1 and ro-4 mutants suggest that cytoplasmic dynein, as well as the Glued/dynactin complex, are required to maintain uniform nuclear distribution in fungal hyphae. We propose that cytoplasmic dynein maintains nuclear distribution through sliding of antiparallel microtubules emanating from neighboring spindle pole bodies.
细胞质动力蛋白是一种多亚基的、依赖微管的机械化学酶，有人提出它在多种细胞内运动中发挥作用，包括细胞器向负端的运输。在体外，通过添加黏合蛋白/动力蛋白激活复合体可刺激动力蛋白介导的囊泡运输，这增加了这两种复合体在体内相互作用的可能性。我们在此报告，丝状真菌粗糙脉孢菌一类表型相同的突变体在编码细胞质动力蛋白亚基或黏合蛋白/动力蛋白激活复合体亚基的基因中存在缺陷。这些被定义为“ropy”的突变体具有卷曲的菌丝和异常的核分布。ro-1编码细胞质动力蛋白的重链，而ro-4编码一种肌动蛋白相关蛋白，它可能是黏合蛋白/动力蛋白激活复合体的主要成分肌动蛋白相关蛋白Arp1（以前称为肌动蛋白-RPV或中心肌动蛋白）的同源物。ro-1和ro-4突变体的表型表明，细胞质动力蛋白以及黏合蛋白/动力蛋白激活复合体是维持真菌菌丝中核均匀分布所必需的。我们提出，细胞质动力蛋白通过相邻纺锤体极体发出的反平行微管的滑动来维持核分布。
