Roles of chitin synthases in hyphal growth and differentiation of filamentous fungi

几丁质合酶在丝状真菌菌丝生长和分化中的作用

• 批准号: 12660066
• 负责人: HORIUCHI Hiroyuki
• 金额: $ 2.3万
• 依托单位: THE UNIVERSITY OF TOKYO
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12660066/
• 关键词: chitin synthase; tip growth; Aspergillus; conidiation; cell wall; 糸状菌

Chitin is a homopolymer of β 1, 4-linked N-acetylglucosamine (GlcNAc) and one of the major cell wall component of many filamentous fungi. We have cloned five genes encoding chitin synthases (chsA - chsD, csmA) from Aspergillus nidulans so far. To elucidate the functional relationships among chsA - chsD, we constructed some sets of double mutants of these genes and analyzed their characteristics in this project. First, we investigate the cell wall organization of chsA chsC double mutant in detail by transmission electron microscopy. The cell walls and septa of the mutant were thickening and central pores of the septa were expanded. These defects were not observed in each single mutant. Chitin content of the cell walls of chsA chsC double mutant increased compared to those of each single mutant and the wild-type strain when they were grown on solid minimal medium. These results suggest that the cell wall defects caused by chsA chsC mutation activated other chitin synthase (s).Next, we constructed chsB chsD, chsA chsB and chsC chsB double mutants and characterized them. The results showed that the importance of chsD increased for hyphal growth under the high osmolarity conditions when the expression of chsB was repressed and that chsA and chsC have some different roles in hyphal growth.

几丁质是β 1，4-连接的N-乙酰葡糖胺（GlcNAc）的均聚物，并且是许多丝状真菌的主要细胞壁组分之一。我们已经从构巢曲霉中克隆了5个几丁质酶基因（chsA - chsD，csmA）.为了阐明chsA - chsD之间的功能关系，我们构建了这两个基因的双突变体，并分析了它们的特性。首先，我们调查的chsA chsC双突变体的细胞壁组织的详细通过透射电子显微镜。突变体细胞壁和隔膜增厚，隔膜中心孔扩大。这些缺陷在每个单一突变体中均未观察到。几丁质含量的chsA chsC双突变体的细胞壁增加相比，每个单突变体和野生型菌株，当它们生长在固体基本培养基上。这些结果表明，chsA chsC突变引起的细胞壁缺陷激活了其他几丁质合成酶。接下来，我们构建了chsB chsD、chsA chsB和chsC chsB双突变体，并对其进行了鉴定。结果表明，在高渗条件下，chsB的表达受到抑制时，chsD对菌丝生长的重要性增加，chsA和chsC在菌丝生长中的作用有所不同。

项目成果

Masayuki Ichinoiya, Takayuki Motoyama, Makoto Fujiwara, Masamichi Takagi, Hiroyuki Horiuchi, and Akinori Ohta: "Repression of chsB expression reveals the functional importance of class IV chitin IV chitin synthase gene chsD in hyphal growth and conidiatio

Masayuki Ichinoiya、Takayuki Motoyama、Makoto Fujiwara、Masamichi Takagi、Hiroyuki Horiuchi 和 Akinori Ohta：“chsB 表达的抑制揭示了 IV 类几丁质 IV 几丁质合酶基因 chsD 在菌丝生长和分生孢子形成中的功能重要性

Ichinomiya et al.: "Repression of chsB expression reveals the functional importance of class IV chitin synthase gene chsD in hyphal growth and conidiation of Aspergillus nidulans"Microbiology. (印刷中). (2002)

Ichinomiya 等人：“chsB 表达的抑制揭示了 IV 类几丁质合酶基因 chsD 在构巢曲霉菌丝生长和分生孢子形成中的功能重要性”微生物学（2002 年出版）。

Ichinomiya, et al.: "Repression of chsB expression reveals the functional importance of class IV chitin synthase gene chsD in hyphal growth and conidiation of Aspergillus nidulans"Microbiology. (印刷中). (2002)

Ichinomiya 等人：“chsB 表达的抑制揭示了 IV 类几丁质合酶基因 chsD 在构巢曲霉菌丝生长和分生孢子形成中的功能重要性”微生物学（2002 年出版）。

Fujiwara et al.: "Evidence that the Aspergillus nidulans class I and II chitin synthase genes, chsC and chsA, share critical roles in hyphal wall integrity and conidiophore development"Journal of Biochemistry. 127. 359-366 (2000)

Fujiwara 等人：“有证据表明构巢曲霉 I 类和 II 类几丁质合酶基因 chsC 和 chsA 在菌丝壁完整性和分生孢子梗发育中具有重要作用”《生物化学杂志》。