Regulation of dimorphism in Saccharomyces cerevisiae: involvement of the novel protein kinase homolog Elm1p and protein phosphatase 2A.
Regulation of dimorphism in Saccharomyces cerevisiae: involvement of the novel protein kinase homolog Elm1p and protein phosphatase 2A.
复制标题
酿酒酵母二态性的调节：新型蛋白激酶同源物 Elm1p 和蛋白磷酸酶 2A 的参与。
DOI：
10.1128/mcb.13.9.5567-5581.1993
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发表时间：
1993
影响因子：
5.3
通讯作者：
Madaule,P
中科院分区：
文献类型：
--
作者：
Blacketer,MJ;Koehler,CM;Coats,SG;Myers,AM;Madaule,P
根据组成型细胞伸长的表型鉴定了酿酒酵母ELM 1、ELM 2和ELM 3。这些基因中的任何一个突变都会导致向假菌丝生长状态的二态转变，其特征在于形成伸长细胞的扩展的支链。此外，elm 1、elm 2和elm 3突变导致细胞在琼脂培养基表面下侵袭性生长。已知酵母是一种二型生物，其作为单细胞酵母或作为称为假菌丝的丝状细胞生长;尽管通常以酵母样形式为主，但在氮饥饿条件下可能发生假菌丝生长。elm 1、elm 2和elm 3突变引起的形态和生理特性与氮饥饿条件下的假菌丝生长非常相似。因此，我们认为ELM 1、ELM 2或ELM 3功能的缺失导致了在氮饥饿条件下正常发生的假菌丝分化途径的组成性执行。ELM 2或ELM 3位点的杂合性显著刺激了氮饥饿条件下假菌丝的形成，ELM 1被分离并编码一种新的蛋白激酶同系物。基因剂量实验还表明，假菌丝的分化响应氮饥饿是依赖于产品的CDC 55，一个假定的B调节亚基蛋白磷酸酶2A，和合成表型观察elm 1cdc 55双突变体。因此，蛋白质磷酸化可能调节分化成假菌丝状态。
TheSaccharomyces cerevisiaegenesELM1,ELM2, andELM3were identified on the basis of the phenotype of constitutive cell elongation. Mutations in any of these genes cause a dimorphic transition to a pseudohyphal growth state characterized by formation of expanded, branched chains of elongated cells. Furthermore,elm1,elm2, andelm3mutations cause cells to grow invasively under the surface of agar medium.S. cerevisiaeis known to be a dimorphic organism that grows either as a unicellular yeast or as filamentous cells termed pseudohyphae; although the yeast-like form usually prevails, pseudohyphal growth may occur during conditions of nitrogen starvation. The morphologic and physiological properties caused byelm1,elm2, andelm3mutations closely mimic pseudohyphal growth occurring in conditions of nitrogen starvation. Therefore, we propose that absence ofELM1,ELM2, orELM3function causes constitutive execution of the pseudohyphal differentiation pathway that occurs normally in conditions of nitrogen starvation. Supporting this hypothesis, heterozygosity at theELM2orELM3locus significantly stimulated the ability to form pseudohyphae in response to nitrogen starvation.ELM1was isolated and shown to code for a novel protein kinase homolog. Gene dosage experiments also showed that pseudohyphal differentiation in response to nitrogen starvation is dependent on the product ofCDC55, a putative B regulatory subunit of protein phosphatase 2A, and a synthetic phenotype was observed inelm1cdc55double mutants. Thus, protein phosphorylation is likely to regulate differentiation into the pseudohyphal state.