title: Expression and activity of glycogen synthase kinase during vitellogenesis and embryogenesis of Rhipicephalus (Boophilus) microplus.
abstract: Glycogen synthase kinase 3 (GSK-3) is classically described as a key enzyme involved in glycogen metabolism in mammals. GSK-3 belongs to a highly conserved family of serine/threonine protein kinases, whose members are involved in hormonal regulation, nuclear signaling, and cell fate determination in higher eukaryotes. We have cloned and characterized the RmGSK-3 gene from Rhipicephalus (Boophilus) microplus tick embryos. DNA and protein sequence analysis depicted high similarity to the corresponding enzyme, from both vertebrate and invertebrate animals. In addition, the mRNA transcription profile identified during embryogenesis was analyzed. We observed that the RmGSK-3 mRNA rapidly decreases from the 1st to 3rd day of development, and increases from the 3rd to 15th day. After the 15th day of development, we observed a near 50% reduction in RmGSK-3 mRNA transcription in comparison to the 1st day. We detected the GSK-3beta isoform in egg homogenates throughout embryogenesis using Western blot analysis. RmGSK-3 mRNA was present in fat body, midgut and ovary from partially and fully engorged adult female ticks. The highest mRNA level was observed in ovaries from both developmental stages and in first-day eggs. Furthermore, RmGSK-3 activity correlated with glycogen content variation. Finally, kinase activity in egg homogenates was inhibited by the specific inhibitor, SB-216763. These data suggest that RmGSK-3beta may be involved in glycogen metabolism regulation during R. microplus embryogenesis.
authors.affiliation: Laboratory of Infectious Diseases, Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, 060-0818, Sapporo, Hokkaido, Japan. logullo@uenf.br
authors.forename: Carlos
authors.initials: C
authors.lastname: Logullo
authors.forename: William H
authors.initials: WH
authors.lastname: Witola
authors.forename: Caroline
authors.initials: C
authors.lastname: Andrade
authors.forename: Leonardo
authors.initials: L
authors.lastname: Abreu
authors.forename: Josiana
authors.initials: J
authors.lastname: Gomes
authors.forename: Itabajara
authors.initials: I
authors.lastname: da Silva Vaz
authors.forename: Saiki
authors.initials: S
authors.lastname: Imamura
authors.forename: Satoru
authors.initials: S
authors.lastname: Konnai
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ohashi
authors.forename: Misao
authors.initials: M
authors.lastname: Onuma
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D038362:Glycogen Synthase Kinase 3 / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D048494:Rhipicephalus / Q000196:embryology* / Q000201:enzymology*; D013997:Time Factors; D014158:Transcription, Genetic
chemical_list: D038362:Glycogen Synthase Kinase 3