title: Hormonal control of GTP cyclohydrolase I gene expression and enzyme activity during color pattern development in wings of Precis coenia.
abstract: Color patterns of butterfly wings are composed of single color points represented by each scale. In the case of Precis coenia, at the end of pupal development, different types of pigments are synthesized sequentially in the differently colored scales beginning with white (pterins) followed by red (ommatins) and then black (melanin). In order to explain how formation of these different colors is regulated, we examined the expression of an mRNA-encoding guanosine triphosphate-cyclohydrolase I (GTP-CH I; EC 3.5.4.16), the first key enzyme in the biosynthesis of pteridines, during pigment formation in the wings of P. coenia. The strongest positive signal was recognized around pigment formation one day before butterfly emergence. This GTP-CH I gene expression is paralleled by GTP-CH I enzyme activity measured in wing extracts. We also investigated the effect of 20-hydroxyecdysone on the expression of GTP-CH I mRNA and the enzyme activity during color formation. The results strongly suggest that the onset and duration of the expression of a GTP-CH I mRNA is triggered by a declining ecdysteroid hormone titer during late pupal development.
authors.affiliation: Biological Laboratory, Center for Natural Science, Kitasato University, 1-15-1, Sagamihara City, Kanagawa 228-8555, Japan. sawada@clas.kitasato-u.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Sawada
authors.forename: M
authors.initials: M
authors.lastname: Nakagoshi
authors.forename: R K
authors.initials: RK
authors.lastname: Reinhardt
authors.forename: I
authors.initials: I
authors.lastname: Ziegler
authors.forename: P B
authors.initials: PB
authors.lastname: Koch
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002080:Butterflies / Q000201:enzymology*; D003116:Color; D004441:Ecdysterone / Q000378:metabolism* / Q000494:pharmacology; D006136:GTP Cyclohydrolase / Q000235:genetics* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D017403:In Situ Hybridization; D008969:Molecular Sequence Data; D012333:RNA, Messenger; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D012333:RNA, Messenger; D004441:Ecdysterone; D006136:GTP Cyclohydrolase