Research article

Granular gland transcriptomes in stimulated amphibian skin secretions

Tianbao CHEN, Susan FARRAGHER, Anthony J. BJOURSON, David F. ORR, Pingfan RAO, Chris SHAW


Amphibian defensive skin secretions are complex, species-specific cocktails of biologically active molecules, including many uncharacterized peptides. The study of such secretions for novel peptide discovery is time-limited, as amphibians are in rapid global decline. While secretion proteome analysis is non-lethal, transcriptome analysis has until now required killing of specimens prior to skin dissection for cDNA library construction. Here we present the discovery that polyadenylated mRNAs encoding dermal granular gland peptides are present in defensive skin secretions, stabilized by endogenous nucleic acid-binding amphipathic peptides. Thus parallel secretory proteome and transcriptome analyses can be performed without killing the specimen in this model amphibian system—a finding that has important implications in conservation of biodiversity within this threatened vertebrate taxon and whose mechanistics may have broader implications in biomolecular science.

  • biodiversity
  • cDNA cloning
  • conservation
  • functional genomics
  • precursor proteins


  • 1 Permanent address: Institute of Biotechnology, University of Fuzhou, Fuzhou 350002, Fujian, People's Republic of China.

  • Abbreviations used: Bm8, Bombina maxima (Chinese large-webbed bell toad) 8kDa polypeptide; Bv8, Bombina variegata (yellow-bellied toad) 8kDa polypeptide; DC, direct current; MAP, mitogen-activated protein; msec, milliseconds; NMU, neuromedin U; poly(A)+, polyadenylated; RACE, rapid amplification of cDNA ends; RT-, reverse transcription.