Hyphal Chain Formation in Candida albicans: Cdc28-Hgc1 Phosphorylation of Efg1 Represses Cell Separation Genes
Hyphal Chain Formation in Candida albicans: Cdc28-Hgc1 Phosphorylation of Efg1 Represses Cell Separation Genes
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DOI：
10.1128/mcb.01502-08
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发表时间：
2009-08-15
影响因子：
5.3
通讯作者：
Liu, Haoping
中科院分区：
文献类型：
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作者：
Wang, Allen;Raniga, Prashna Pala;Liu, Haoping
细胞链的形成是真菌丝状生长的一个特征。在多形性真菌中它是如何调控发育的尚不清楚。在白色念珠菌中，酵母生长过程中间隔的降解是由G中表达的Ace2激活基因编码的酶完成的(1)。我们发现细胞周期蛋白依赖性激酶Cdc28-Hgc1（菌丝特异性G(1)细胞周期蛋白）磷酸化一个保守的发育调节因子Efg1，下调G(1)菌丝生长过程中的Ace2靶基因。在Efg1保守的Cdc28磷酸化位点含有苏氨酸到丙氨酸突变的菌株显示这些基因的菌丝特异性抑制缺失和受损的细胞链形成，模拟hgc1缺失，而含有苏氨酸到天冬氨酸突变的菌株导致酵母生长过程中这些基因和细胞链形成的下调。此外，磷酰亚胺突变可以抑制hgc1的细胞分离缺陷。在菌丝生长过程中，Efg1也表现出与Ace2靶基因启动子的优先关联。我们发现Ace2和Efg1的趋同调控定义了细胞链形成的转录程序。
Cell chain formation is a characteristic of filamentous growth in fungi. How it is regulated developmentally in multimorphic fungi is not known. In Candida albicans, degradation of septa during yeast growth is accomplished by enzymes encoded by Ace2 activated genes expressed in G(1). We found that phosphorylation of a conserved developmental regulator, Efg1, by the cyclin-dependent kinase Cdc28-Hgc1 (hypha-specific G(1) cyclin) downregulates Ace2 target genes during hyphal growth in G(1). A strain containing a threonine-to-alanine mutation at a conserved Cdc28 phosphorylation site of Efg1 displays a loss of hypha-specific repression of these genes and impaired cell chain formation, mimicking the hgc1 deletion, whereas a strain containing the threonine to aspartic acid mutation leads to a downregulation of these genes and cell chain formation during yeast growth. Furthermore, the phosphomimic mutation can suppress cell separation defects of hgc1. Efg1 also displays preferential association with Ace2 target gene promoters during hyphal growth. We show that convergent regulation of Ace2 and Efg1 defines the transcriptional program of cell chain formation.