title: Regulated expression of the HNK-1 carbohydrate is essential for medaka (Oryzias latipes) embryogenesis.
abstract: Carbohydrates are known to play essential roles in various biological processes including development. However, it remains largely unknown which carbohydrate structure takes part in each biological event. Here, we examined the roles of the human natural killer-1 (HNK-1) carbohydrate in medaka embryogenesis. We first cloned two medaka glucuronyltransferases, GlcAT-P and GlcAT-S, key enzymes for HNK-1 biosynthesis. Overexpression of these glucuronyltransferases affected morphogenetic processes. In addition, loss-of-function experiments revealed that GlcAT-P is physiologically indispensable for head morphogenesis and GlcAT-P depletion also led to markedly increased apoptosis. However, even when the apoptosis was blocked, abnormal head morphogenesis caused by GlcAT-P depletion was still observed, indicating that apoptosis was not the main cause of the abnormality. Moreover, in situ hybridization analyses indicated that GlcAT-P depletion resulted in the abnormal formation of the nervous system but not in cell specification. These results suggest that tight regulation of HNK-1 expression is essential for proper morphogenesis of medaka embryos.
authors.affiliation: Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Anzai
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Tonoyama
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ikeda
authors.forename: Toshisuke
authors.initials: T
authors.lastname: Kawasaki
authors.forename: Shogo
authors.initials: S
authors.lastname: Oka
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D018959:CD57 Antigens / Q000096:biosynthesis*; D004625:Embryo, Nonmammalian / Q000502:physiology; D014453:Glucuronosyltransferase / Q000378:metabolism*; D008969:Molecular Sequence Data; D009990:Oryzias / Q000196:embryology* / Q000378:metabolism
chemical_list: D018959:CD57 Antigens; D014453:Glucuronosyltransferase