Comprehensive expression analysis of the cell wall related genes in Aspergillus oryzae using the disruption mutant of protein processing enzyme gene (kexB).

Osamu Mizutani, Tomonori Fujioka, Youhei Yamagata, Keietsu Abe, and Tasuku Nakajima.


KexB is a processing proteolytic enzyme in fungi. To understand the involvement of KexB in protein processing, we cloned and disrupted kexB gene (DkexB) in A. oryzae. The DkexB strain formed small and shrunk colonies with significantly poor conidia generation on the Czapek-Dox (CD) agar plate. It also showed hyper-branched mycelia in liquid culture. When DkexB was cultivated under the various environmental conditions, we noticed that the phenotypes of the DkexB were restored under high osmolarity in both solid and liquid culture conditions. As a result of the observation of the phenotypes, we speculated that KexB might play an important role in processing of the gene products related to branching and conidia formation in solid cultivation. Then, to investigate the role of KexB in the expression of morphogenesis related genes in A. oryzae, we performed comprehensive gene expression analysis between the DkexB and the wild-type by using DNA microarrays containing 2,000 A. oryzae cDNAs. As a result, expression levels of ca.300 genes in the DkexB were significantly higher than the corresponding genes in the wild-type under solid culture conditions. In particular, the expression levels of chsB, chsC and gel2, which encode the cell wall synthesis enzymes, increased in the DkexB. Expression levels of the cell wall biosynthesis related genes in various growth stages will be also compared between the DkexB and the wild-type.

abstract No: 

Fungal Genet. Newsl. 50 (Supl):abstract

Full conference title: 

22nd Fungal Genetics Conference
    • Fungal Genetics Conference 22nd (2001)