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

• Project/Area Number: 12660066
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 応用微生物学・応用生物化学
• Research Institution: THE UNIVERSITY OF TOKYO
• Principal Investigator: HORIUCHI Hiroyuki Graduate School of Agriculture and Life Sciences, The University of Tokyo, Associate Professor, 大学院・農学生命科学研究科, 助教授 (00209280)
• Project Period (FY): 2000 – 2001
• Project Status: Completed (Fiscal Year 2001)
• Budget Amount: ¥3,600,000 (Direct Cost: ¥3,600,000); Fiscal Year 2001: ¥1,400,000 (Direct Cost: ¥1,400,000); Fiscal Year 2000: ¥2,200,000 (Direct Cost: ¥2,200,000)
• Keywords: chitin synthase / tip growth / Aspergillus / conidiation / cell wall / 糸状菌

Research Abstract

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.

Research Products

• [Publications] 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)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] 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 conidiation of Aspergillus nidulans"Microbiology. (in press). (2002)
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] 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)
• [Publications] 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)