Freedman Toby, Porter Alexandra, Haarer Brian
Section of Molecular Cell and Developmental Biology, The University of Texas, Austin, TX 78712, USA2.
Department of Biochemistry and Molecular Biology, Harvard University, Cambridge, MA 02138, USA1.
Microbiology (Reading). 2000 Nov;146 ( Pt 11):2833-2843. doi: 10.1099/00221287-146-11-2833.
Analysis of bud-site selection in the yeast Saccharomyces cerevisiae has helped to identify many genes that are generally important for eukaryotic cell polarization. Colony morphology screens were used to identify factors relevant to the process of bipolar budding in yeast. Mutants defective in bipolar budding were identified by virtue of their inability to grow as pseudohyphae in a haploid bud3 background. A mutant allele of the MYO2 gene, encoding a class-V unconventional myosin was identified that perturbs bipolar budding without affecting axial budding and without grossly affecting the role of Myo2p in secretion and maintenance of the actin cytoskeleton. Several genes were also identified whose products, when overexpressed, are capable of disrupting bipolar budding. Among these are the actin-monomer-binding protein profilin and the Aip3p/Bud6p-interacting protein Atc1p. The results strongly support involvement of the actin cytoskeleton in the establishment of bipolar budding and in the maintenance of pseudohyphal growth.
对酿酒酵母芽位选择的分析有助于鉴定许多对真核细胞极化普遍重要的基因。通过菌落形态筛选来鉴定与酵母双极出芽过程相关的因子。在单倍体bud3背景下，不能以假菌丝形式生长的突变体被鉴定为双极出芽缺陷型。鉴定出一个编码V类非常规肌球蛋白的MYO2基因突变等位基因，它扰乱双极出芽，但不影响轴向出芽，也不严重影响Myo2p在肌动蛋白细胞骨架分泌和维持中的作用。还鉴定出几个基因，其产物在过表达时能够破坏双极出芽。其中包括肌动蛋白单体结合蛋白原肌球蛋白以及与Aip3p/Bud6p相互作用的蛋白Atc1p。结果有力地支持了肌动蛋白细胞骨架参与双极出芽的建立和假菌丝生长的维持。
