Evidence that the Aspergillus nidulans class I and class II chitin synthase genes, chsC and chsA, share critical roles in hyphal wall integrity and conidiophore development
Evidence that the Aspergillus nidulans class I and class II chitin synthase genes, chsC and chsA, share critical roles in hyphal wall integrity and conidiophore development
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DOI：
10.1093/oxfordjournals.jbchem.a022616
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发表时间：
2000-03-01
影响因子：
2.7
通讯作者：
Takagi, M
中科院分区：
文献类型：
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作者：
Fujiwara, M;Ichinomiya, M;Takagi, M
尽管许多几丁质合酶基因已在广泛的真菌物种中被发现，但关于它们在真菌形态发生中的作用的报道却很少。在大多数情况下，单基因破坏或替换并不能揭示它们的功能，可能是因为它们之间的功能冗余。我们获得了分别编码非必需II类和I类几丁质合酶的构巢曲霉chsA和chsC基因的无效突变体。 Delta chsA Delta chsC 突变体在补充有十二烷基硫酸钠 (SDS)、高浓度盐、几丁质结合染料或几丁质合酶竞争性抑制剂的培养基上表现出生长缺陷，表明菌丝壁完整性丧失。此外，在其无性发育过程中，在显微镜下观察到双突变体的显着异常。分生孢子梗数量急剧减少，有趣的是，次生分生孢子梗偶尔会从初级分生孢子梗的囊泡中产生，这些分生孢子梗的形态与构巢曲霉发育突变体、水母（medA）、算盘（abaA）和某些种类的鬃毛（brlA）相似，原位染色模式表明chsA主要在分生孢子中表达， ChsA 和 ChsC 在菌丝壁完整性和分化方面具有共同的关键功能。
Although many chitin synthase genes have been identified in a broad range of fungal species, there have been only a few reports about their role in fungal morphogenesis, In most cases, single gene disruption or replacement did not reveal their function, possibly because of functional redundancy among them. We obtained null mutants of Aspergillus nidulans chsA and chsC genes encoding non-essential class II and class I chitin synthases, respectively. The Delta chsA Delta chsC mutant exhibited growth defects on media supplemented with sodium dodecyl sulfate (SDS), high concentration of salts, chitin-binding dyes, or chitin synthase competitive inhibitors, suggesting loss of integrity of hyphal wall. Moreover, remarkable abnormalities of the double mutant were observed microscopically during its asexual development. The conidiophore population was drastically reduced, Interestingly, secondary conidiophores were occasionally produced from vesicles of the primary ones, The morphology of these conidiophores was similar to those of the A. nidulans developmental mutants, medusa (medA), abacus (abaA), and some kinds of bristle (brlA), lit situ staining patterns suggested that chsA was mainly expressed in the metulae, phialides, and conidia, whereas chsC was expressed in hyphae as well as conidiophores, These results suggest that ChsA and ChsC share critical functions in hyphal wall integrity and differentiation.