Wedlich-Söldner R, Bölker M, Kahmann R, Steinberg G
Institut für Genetik und Mikrobiologie, LMU, Maria-Ward-Strasse 1a, D-80638 München, Germany.
EMBO J. 2000 May 2;19(9):1974-86. doi: 10.1093/emboj/19.9.1974.
We identified a temperature-sensitive mutant of the plant pathogenic fungus Ustilago maydis that is defective in the polar distribution of cell wall components and shows abnormal morphology. The affected gene, yup1, was cloned by complementation. It encodes a putative target soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptor (t-SNARE), suggesting a function in membrane fusion. A Yup1-GFP fusion protein localized to vesicles that showed rapid saltatory motion along microtubules. These vesicles are part of the endocytic pathway and accumulate at sites of active growth, thereby supporting the expansion of the hyphal tip. In yup1(ts) cells, endocytosis is impaired and accumulation of Yup1-carrying endosomes at cell poles is abolished, resulting in apolar distribution of wall components and morphological alterations. This suggests that a membrane recycling process via early endosomes supports polar growth of U. maydis.
我们鉴定出一种植物致病真菌玉米黑粉菌（Ustilago maydis）的温度敏感突变体，该突变体在细胞壁成分的极性分布方面存在缺陷，并表现出异常形态。通过互补克隆出了受影响的基因yup1。它编码一种假定的靶可溶性N-乙基马来酰亚胺敏感融合蛋白附着蛋白受体（t-SNARE），表明其在膜融合中发挥作用。一种Yup1-GFP融合蛋白定位于囊泡，这些囊泡沿微管显示出快速跳跃运动。这些囊泡是内吞途径的一部分，并在活跃生长部位积累，从而支持菌丝尖端的扩展。在yup1(ts)细胞中，内吞作用受损，携带Yup1的内体在细胞极的积累被消除，导致壁成分的非极性分布和形态改变。这表明通过早期内体的膜循环过程支持玉米黑粉菌的极性生长。
