title: Comparative expression analysis of multiple PDK genes in Xenopus laevis during oogenesis, maturation, fertilization, and early embryogenesis.
abstract: The complete family of expressed pyruvate dehydrogenase kinase (PDK) genes in the tissues of the African clawed frog, Xenopus laevis, consists of four members. Our previous study [Terazawa, Y., Tokmakov, A., Shirouzu, M., Yokoyama, S., 2005. Molecular cloning and expression analysis of PDK family genes in Xenopus laevis reveal oocyte-specific PDK isoform. Biochem. Biophys. Res. Commun. 338, 1798-1804] revealed that expression patterns of PDK genes differ greatly in the oocytes and somatic tissues of the adult frog. In the present work, using quantitative reverse-transcriptase PCR analysis, we demonstrate that the major transition from the oocyte-specific to somatic tissue-specific xPDK expression pattern occurs at the late stages of Xenopus embryogenesis after mid-blastula transition (MBT). Also, we show that the content of mRNA for xPDKo3, which is the predominant PDK isoform in oocytes and eggs, increases by about 3-fold during maturation. Other PDK family genes are down-regulated during oogenesis, thus being at their lowest expression levels in the grown-up oocytes, matured eggs, and early embryos. The expression of all PDK genes increases several-fold in the embryogenesis following MBT. Analysis of protein expression using an antibody raised against C-terminal of xPDKo3 confirmed isoform-specific up-regulation of xPDKo3 late in maturation and revealed cytoplasmic and mitochondrial localization of this protein. Bioinformatics and mass-spectrometric analyses allowed identification of an N-terminal mitochondrial targeting signal and a peptide cleavage site in xPDKo3 molecule.
authors.affiliation: Research Center for Environmental Genomics, Kobe University, Rokko dai 1-1, Nada, Kobe, Hyogo 657 8501, Japan. tokmak@phoenix.kobe-u.ac.jp
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Tokmakov
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Terazawa
authors.forename: Mariko
authors.initials: M
authors.lastname: Ikeda
authors.forename: Mikako
authors.initials: M
authors.lastname: Shirouzu
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Fukami
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Yokoyama
mesh_terms: D000818:Animals; D001483:Base Sequence; D047108:Embryonic Development / Q000235:genetics*; D005306:Fertilization / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental; D007527:Isoenzymes / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology; D009865:Oocytes / Q000201:enzymology; D009866:Oogenesis / Q000235:genetics*; D054730:Protein Interaction Domains and Motifs; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D015854:Up-Regulation; D029867:Xenopus Proteins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D014982:Xenopus laevis
chemical_list: D007527:Isoenzymes; D000081382:Pyruvate Dehydrogenase Acetyl-Transferring Kinase; D029867:Xenopus Proteins; D017346:Protein Serine-Threonine Kinases