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Journal of Molecular Evolution

, Volume 53, Issue 1, pp 31–38 | Cite as

Rapid Diversification of RNase A Superfamily Ribonucleases from the Bullfrog, Rana catesbeiana

  • Helene F.  Rosenberg
  • Jianzhi  Zhang
  • You-Di  Liao
  • Kimberly D.  Dyer

Abstract.

We present sequences of five novel RNase A superfamily ribonuclease genes of the bullfrog, Rana catesbeiana. All five genes encode ribonucleases that are similar to Onconase, a cytotoxic ribonuclease isolated from oocytes of R. pipiens. With amino acid sequence data from 14 ribonucleases from three Rana species (R. catesbeiana, R. japonica, and R. pipiens), we have constructed bootstrap-supported phylogenetic trees that reorganize these ribonucleases into five distinct lineages—the pancreatic ribonucleases (RNases 1), the eosinophil-associated ribonucleases (RNases 2, 3, and 6), the ribonucleases 4, the angiogenins (RNases 5) and the Rana ribonucleases—with the Rana ribonucleases no more closely related to the angiogenins than they are to any of the other ribonuclease lineages shown. Further phylogenetic analysis suggests the division of the Rana ribonucleases into two subclusters (A and B), with positive (Darwinian) selection (dN/dS > 1.0) and an elevated rate of radical nonsynonymous substitution (dR) contributing to the rapid diversification of ribonucleases within each cluster. This pattern of evolution—rapid diversification via positive selection among sequences of a multigene cluster—bears striking resemblance to what we have described for the eosinophil-associated ribonuclease genes of the rodent Mus musculus, a finding that may have implications with respect the physiologic function of this unique family of proteins.

Key words: Ribonucleases — Molecular evolution — Amphibians 

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Copyright information

© Springer-Verlag New York Inc. 2001

Authors and Affiliations

  • Helene F.  Rosenberg
    • 1
  • Jianzhi  Zhang
    • 1
  • You-Di  Liao
    • 2
  • Kimberly D.  Dyer
    • 1
  1. 1.Laboratory of Host Defenses, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MarylandUS
  2. 2.Institute of Biomedical Sciences, Academia Sinica, Taipei 115, TaiwanTW

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