Repression of chsB expression reveals the functional importance of class IV chitin synthase gene chsD in hyphal growth and conidiation of Aspergillus nidulans
Repression of chsB expression reveals the functional importance of class IV chitin synthase gene chsD in hyphal growth and conidiation of Aspergillus nidulans
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DOI：
10.1099/00221287-148-5-1335
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发表时间：
2002-05-01
期刊：
影响因子：
2.8
通讯作者：
Ohta, A
中科院分区：
文献类型：
--
作者：
Ichinomiya, M;Motoyama, T;Ohta, A
分析了构巢曲霉几丁质合成酶基因chsB和chsD的功能。首先，构建了条件chsB突变体，其中chsB的表达在A. nidulans。在抑制条件下，突变体生长缓慢，产生高度分支的菌丝，支持的想法，chsB参与正常菌丝生长。chsB在分生孢子的参与也被证明。接下来，构建了chsB和chsD的双突变体，其中chsB置于alcA启动子的控制下，chsD被A的argB基因取代。nidulans。在高渗透压条件下，这些双突变体比chsB单突变体生长得更慢。双突变体的菌丝似乎比chsB单突变体的菌丝更混乱。有人还发现，ChsD的功能涉及分生孢子时，chsB的表达是有限的。这些结果表明在缺乏chsB表达的情况下ChsD功能的重要性。以大肠杆菌lacZ为报告基因，通过对ChsB和ChsD空间表达模式的分析，证实了ChsB和ChsD在菌丝生长和分生孢子形成中的作用。
The functions of two previously identified chitin synthase genes in Aspergillus nidulans, chsB and chsD, were analysed. First, a conditional chsB mutant was constructed in which the expression of chsB is under the control of a repressible promoter, the alcA promoter, of A. nidulans. Under repressing conditions, the mutant grew slowly and produced highly branched hyphae, supporting the idea that chsB is involved in normal hyphal growth. The involvement of chsB in conidiation was also demonstrated. Next, double mutants of chsB and chsD were constructed, in which chsB was placed under the control of the alcA promoter and chsD was replaced with the argB gene of A. nidulans. These double mutants grew more slowly than the chsB single mutant under high-osmolarity conditions. The hyphae of the double mutant appeared to be more disorganized than those of the chsB single mutant. It was also found that ChsD was functionally implicated in conidiation when the expression of chsB was limited. These results indicate the importance of the ChsD function in the absence of chsB expression. The roles of ChsB and ChsD in hyphal growth and in conidiation were supported by the analysis of the spatial expression patterns of chsB and chsD, using lacZ of Escherichia coli as a reporter gene.