Developmental and triiodothyronine-induced expression of genes encoding preprotemporins in the skin of Tago's brown frog Rana tagoi

Aya Ohnuma, J. Michael Conlon, Hiroaki Kawasaki, Shawichi Iwamuro

Research output: Contribution to journalArticlepeer-review

27 Citations (Scopus)

Abstract

Using RT-PCR, two cDNAs encoding preprotemporins were cloned from a total RNA preparation of the skin of Tago's brown frog Rana tagoi. Preprotemporin-1TGa cDNA directs the synthesis of temporin-1TGa (FLPILGKLLSGIL.NH2) previously isolated from R. tagoi skin. Preprotemporin-1TGb cDNA directs the synthesis of a novel 16-amino-acid-residue peptide (AVDLAKIANKVLSSLF.NH2) that, atypically for members of the temporin family, inhibits the growth of Gram-negative bacteria more effectively than Gram-positive bacteria. Preprotemporin-1TGa mRNA and preprotemporin-1TGb mRNA were not detected in skin prior to the onset of metamorphosis (stage 35) but the levels of the transcripts increased markedly during metamorphosis reaching a maximum at stage 38. Exposure of adult animals to 10-8 M triiodothyronine (T3) for 72 h enhanced expression of the preprotemporin-1TGb gene (approximately threefold) but did not significantly change the level of expression of the preprotemporin-1TGa gene. Exposure of the animals to 10-8 M T3 and 10-6 M bisphenol A, an endocrine disrupting chemical that potently inhibits the action of thyroid hormones (THs), reduced expression of the preprotemporin-1TGb gene by 10-fold and the preprotemporin-1TGa gene by threefold. We propose that T3-stimulated synthesis of antimicrobial peptides is important in protecting the animal against microorganisms, particularly at metamorphosis and during skin moulting, but environmental pollutants can inhibit peptide synthesis and render the animal susceptible to invasion by pathogens.

Original languageEnglish
Pages (from-to)242-250
Number of pages9
JournalGeneral and Comparative Endocrinology
Volume146
Issue number3
DOIs
Publication statusPublished - May 1 2006
Externally publishedYes

Keywords

  • Antimicrobial peptide
  • Bisphenol A
  • Endocrine disruptor
  • Frog skin
  • Temporin
  • Triidothryonine

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Endocrinology

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