カワタ　タケフミ   Kawata Takefumi   川田　健文    所属   東邦大学  理学部 生物学科    職種   教授
論文種別	原著
言語種別	英語
査読の有無	査読あり
表題	A Dictyostelium cellobiohydrolase orthologue that affects developmental timing
掲載誌名	正式名：Development Genes and Evolution ISSNコード：0949-944X
出版社	Springer
巻・号・頁	224(1),pp.25-35
著者・共著者	Kunii M†, Yasuno M†, Shindo Y†, Kawata T＊†
担当区分	責任著者
発行年月	2014/02
概要	Dictyostelium discoideum is a facultative multicellular amoebozoan with cellulose in the stalk and spore coat of its fruiting body as well as in the extracellular matrix of the migrating slug. The organism also harbors a number of cellulase genes. One of them, cbhA, was identified as a candidate cellobiohydrolase gene based on the strong homology of its predicted protein product to fungal cellobiohydrolase I (CBHI). Expression of the cbhA was developmentally regulated, with strong expression in the spores of the mature fruiting body. However, a weak but detectable level of expression was observed in the extracellular matrix at the mound — tipped finger stages, in prestalk O cells, and in the slime sheath of the migrating slug — late culminant stages. A null mutant of the cbhA showed almost normal morphology. However, the developmental timing of the mutant was delayed by 2–4 h. When a c-Myc epitope-tagged CbhA was expressed, it was secreted into the culture medium and was able to bind crystalline cellulose. The CbhA-myc protein was glycosylated, as demonstrated by its ability to bind succinyl concanavalin A-agarose. Moreover, conditioned medium from the cbhA-myc oe strain displayed 4-methylumbelliferyl β-d-cellobioside (4-MUC) digesting activity in Zymograms in which conditioned medium was examined via native-polyacrylamide gel electrophoresis or spotted on an agar plate containing 4-MUC, one of the substrates of cellobiohydrolase. Taken together, these findings indicate that Dictyostelium CbhA is an orthologue of CBH I that is required for a normal rate of development.
DOI	10.1007/s00427-013-0460-x