title: Cloning and characterization of a chitinase-encoding gene (chiA) from Aspergillus nidulans, disruption of which decreases germination frequency and hyphal growth.
abstract: We cloned a chitinase-encoding gene from Aspergillus nidulans by polymerase chain reaction using degenerated oligonucleotide primers designed from the conserved amino acid sequences among chitinases from yeasts and Rhizopus spp. The cloned gene, named chiA, encoded a polypeptide consisting of 660 amino acids. Disruption of chiA had no effect on hyphal or conidiophore morphology, but germination frequency and hyphal growth rate decreased substantially. Expression of chiA was investigated using Escherichia coli beta-galactosidase as a reporter enzyme. The beta-galactosidase activity was present during hyphal growth and increased twice as the conidiophores developed. In situ staining of beta-galactosidase activity found high expression in metulae, phialides, and conidia during conidiophore development, indicating that the expression of chiA is developmentally regulated. This is the first report to isolate a chitinase gene from A. nidulans and investigate its functions using the gene disruption technique and gene fusion methods in filamentous fungi.
authors.affiliation: Department of Biotechnology, University of Tokyo, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Takaya
authors.forename: D
authors.initials: D
authors.lastname: Yamazaki
authors.forename: H
authors.initials: H
authors.lastname: Horiuchi
authors.forename: A
authors.initials: A
authors.lastname: Ohta
authors.forename: M
authors.initials: M
authors.lastname: Takagi
mesh_terms: D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D001483:Base Sequence; D002688:Chitinases / Q000235:genetics* / Q000502:physiology; D003001:Cloning, Molecular; D004271:DNA, Fungal; D005656:Fungal Proteins / Q000235:genetics* / Q000502:physiology; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; D002688:Chitinases; C094590:chitinase ChiA