Aspergillus nidulans ChiA is a glycosylphosphatidylinositol (GPI)-anchored chitinase specifically localized at polarized growth sites.
It is believed that chitinases play important physiological roles in filamentous fungi since chitin is one of the major cell wall components in these organisms. In this paper we investigated a chitinase gene, chiA, of Aspergillus nidulans and found that the gene product of chiA consists of a signal sequence, a region including chitinase consensus motifs, a Ser/Thr/Pro-rich region and a glycosylphosphatidylinositol (GPI)-anchor attachment motif. Phosphatidylinositol-specific phospholipase C treatment of the fusion protein of ChiA and enhanced green fluorescent protein (EGFP)-ChiA-EGFP-caused a change in its hydrophobicity, indicating that ChiA is a GPI-anchored protein. ChiA-EGFP localized at the germ tubes of conidia, at hyphal branching sites and hyphal tips. chiA expression was specifically high during conidia germination and in the marginal growth regions of colonies. These results suggest that ChiA functions as a GPI-anchored chitinase at the sites where cell wall remodeling and/or cell wall maturation actively take place.
Yamazaki
Harutake
H
Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
Tanaka
Aya
A
Kaneko
Jun-ichi
J
Ohta
Akinori
A
Horiuchi
Hiroyuki
H
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D002688:Chitinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D025301:Hyphae / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013172:Spores, Fungal / Q000201:enzymology / Q000235:genetics / Q000254:growth & development
D005656:Fungal Proteins; D017261:Glycosylphosphatidylinositols; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D002688:Chitinases