Role of a mitogen-activated protein kinase pathway during conidial germination and hyphal fusion in Neurospora crassa
Role of a mitogen-activated protein kinase pathway during conidial germination and hyphal fusion in Neurospora crassa
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DOI：
10.1128/ec.3.2.348-358.2004
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发表时间：
2004-04-01
期刊：
影响因子：
--
通讯作者：
Glass, NL
中科院分区：
文献类型：
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作者：
Pandey, A;Roca, MG;Glass, NL
有丝分裂原活化蛋白（MAP）激酶信号通路在真核生物中普遍存在且进化保守。MAP激酶途径由MAP激酶、MAP激酶激酶和MAP激酶组成;激活受顺序磷酸化调节。丝状真菌粗糙脉孢菌的基因组序列分析已经确定了三个MAP激酶途径的组成部分。在N. crassa，MAK-2，与酿酒酵母Fus 3 p和Kss 1 p相似，分别参与有性生殖和有性生殖。在这项研究中，我们表明，一个N。在MAK-2中破坏的crassa突变体表现出多效性表型：解阻遏的分生孢子、缩短的气生菌丝、缺乏营养菌丝融合、雌性不育和自主子囊孢子致死。我们评估了在分生孢子萌发和早期菌落发育过程中MAK-2的磷酸化。MAK-2磷酸化的峰值水平与芽管伸长、分支和分生孢子萌发之间的菌丝融合事件最密切相关。MAP激酶（NRC-1）是N. crassa nrc-1基因座，与S.啤酒。nrc-1突变体与mak-2突变体具有许多相同的表型性状，特别是菌丝融合突变体。我们发现，MAK-2的磷酸化在早期的殖民地发展是依赖于NRC-1的存在下，并假设磷酸化的MAK-2是需要菌丝融合事件发生在分生孢子萌发。
Mitogen-activated protein (MAP) kinase signaling pathways are ubiquitous and evolutionarily conserved in eukaryotic organisms. MAP kinase pathways are composed of a MAP kinase, a MAP kinase kinase, and a MAP kinase kinase kinase; activation is regulated by sequential phosphorylation. Components of three MAP kinase pathways have been identified by genome sequence analysis in the filamentous fungus Neurospora crassa. One of the predicted MAP kinases in N. crassa, MAK-2, shows similarity to Fus3p and Kss1p of Saccharomyces cerevisiae, which are involved in sexual reproduction and filamentation, respectively. In this study, we show that an N. crassa mutant disrupted in mak-2 exhibits a pleiotropic phenotype: derepressed conidiation, shortened aerial hyphae, lack of vegetative hyphal fusion, female sterility, and autonomous ascospore lethality. We assessed the phosphorylation of MAK-2 during conidial germination and early colony development. Peak levels of MAK-2 phosphorylation were most closely associated with germ tube elongation, branching, and hyphal fusion events between conidial germlings. A MAP kinase kinase kinase (NRC-1) is the predicted product of N. crassa nrc-1 locus and is a homologue of STE11 in S. cerevisiae. An nrc-1 mutant shares many of the same phenotypic traits as the mak-2 mutant and, in particular, is a hyphal fusion mutant. We show that MAK-2 phosphorylation during early colony development is dependent upon the presence of NRC-1 and postulate that phosphorylation of MAK-2 is required for hyphal fusion events that occur during conidial germination.