title: Differential expression of nucleoside diphosphate kinases (NDPK/NM23) during Xenopus early development.
abstract: In Xenopus laevis, three nucleoside diphosphate kinase (NDPK) monomers have been described (NDPK X1, X2 and X3) (Ouatas et al., 1997). In eucaryotes, this kinase is known as a hetero- or homohexamer. Here, we examine the distribution of the enzyme and its different subunit mRNAs during oogenesis and early embryogenesis of Xenopus laevis, respectively by immunohistofluorescence and whole-mount in situ hybridization. These analyses show that NDPKs and their mRNAs are differentially distributed throughout the oocyte and early embryos with a high level of transcription in somites and brain. We emphasize two points. First, each mRNA displays a distinct subcellular localization in somites, suggesting a complex regulation of NDPK genes both at the transcriptional and translational level and a possible involvement of NDPK X2 homohexamers in the dorsal muscle differentiation. Second, in oocytes and early embryos, the proteins are mainly localized in the nucleus, suggesting a new mechanism for their nuclear import, since they do not possess any known nuclear import sequences.
authors.affiliation: Centre de Génétique Moléculaire, CNRS, Gif-sur-Yvette, France. ouatas@mnhn.fr
authors.forename: T
authors.initials: T
authors.lastname: Ouatas
authors.forename: M
authors.initials: M
authors.lastname: Sélo
authors.forename: Z
authors.initials: Z
authors.lastname: Sadji
authors.forename: J
authors.initials: J
authors.lastname: Hourdry
authors.forename: H
authors.initials: H
authors.lastname: Denis
authors.forename: A
authors.initials: A
authors.lastname: Mazabraud
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D020559:Monomeric GTP-Binding Proteins; D054778:NM23 Nucleoside Diphosphate Kinases; D009687:Nuclear Proteins / Q000378:metabolism; D009701:Nucleoside-Diphosphate Kinase / Q000378:metabolism*; D014176:Protein Biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic / Q000235:genetics; D014981:Xenopus / Q000196:embryology*
chemical_list: D054778:NM23 Nucleoside Diphosphate Kinases; D009687:Nuclear Proteins; D012333:RNA, Messenger; D014157:Transcription Factors; D009701:Nucleoside-Diphosphate Kinase; D020559:Monomeric GTP-Binding Proteins