Functional analysis of orphan glycosyltransferases involved in mucin-type O-glycosylation in the brain

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K07015
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Functional biochemistry
• Research Institution: Kyoto Sangyo University
• Principal Investigator: KUROSAKA Akira 京都産業大学, 総合生命科学部, 教授 (90186536)
• Co-Investigator(Kenkyū-buntansha): 中山 喜明 神戸薬科大学, 薬学部, 准教授 (40512455) ; 加藤 啓子 京都産業大学, 総合生命科学部, 教授 (90252684) ; 中村 直介 京都産業大学, 総合生命科学部, 研究助教 (30424964)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: ムチン型糖鎖 / 糖転移酵素 / ゲノム編集 / ゼブラフィッシュ / 初期発生

Outline of Final Research Achievements

Biosynthesis of mucin-type carbohydrates is initiated and modified by the action of polypeptide N-acetylgalactosaminyltransferases (GalNAc-Ts), and a sialyltransferase, ST3GalIV. This research investigates functions of four vertebrate-specific GalNAc-T isozymes, in vitro activities of which have not been reported so far, and ST3GalIV, during early development of zebrafish. First, all the genes for GalNAc-T8, -T9, -T17, -T18, and ST3GalIV were isolated and they were found to have tissue-specific, although overlapping, expression patterns, Next, mutant zebrafish that lack these genes except GalNAc-T8, ST3GalIV were established, and phenotypes of early embryos were analyzed. We found that the genes have overlapping functions, and compensate the activity of a deleted isozyme in zebrafish.
Thus, deletions of more than one isozyme would be necessary to observe phenotypic alterations.

Free Research Field

生化学，糖鎖生物学

Academic Significance and Societal Importance of the Research Achievements

本研究はゲノム編集を利用して，ムチン型糖鎖合成に関わる酵素（GalNAc-T）欠失ゼブラフィッシュ変異体を作製し，初期発生におけるムチン型糖鎖の機能を解明しようとするものである．GalNAc-Tは大きな遺伝子ファミリーを形成するが本研究では，in vitroの酵素活性が検出されていないオーファンアイソザイムの機能解析を行っている．特にこれらの中のGalNAc-T17は神経細胞に特異的に発現し，知的障害，特徴的な認知特性を特徴とするウィリアムズ症候群に関連する遺伝子として知られている．本研究を通じて，糖転移酵素およびムチン型糖鎖の脳における機能の解明が期待される．