Sexual Plant Reproduction

, Volume 17, Issue 2, pp 81–87

Isolation of S-RNase binding proteins from Solanum chacoense: identification of an SBP1 (RING finger protein) orthologue

  • Martin O’Brien
  • Geneviève Major
  • Sier-Ching Chantha
  • Daniel P. Matton
Original Article

DOI: 10.1007/s00497-004-0218-8

Cite this article as:
O’Brien, M., Major, G., Chantha, SC. et al. Sex Plant Reprod (2004) 17: 81. doi:10.1007/s00497-004-0218-8

Abstract

Currently, the most attractive working model of gametophytic self-incompatibility (SI) involving S-RNases postulates the presence of an inhibitor protein or complex expressed in pollen tubes that would counteract the cytotoxic effect of the ribonuclease activity of the S-RNase. Since it has been previously shown that allele-specific recognition is mediated through the hypervariable domain sequence of the S-RNase, we have targeted this region to isolate pollen-expressed interacting proteins in the yeast two-hybrid system. One of the isolated proteins corresponds to a RING finger protein highly similar to the previously isolated SBP1 protein from Petunia hybrida. This protein is postulated to be part of the RING finger E3 ligase family. The ScSBP1 gene is expressed in almost all tissues tested, suggesting a more general role than only being involved in SI. Although the ScSBP1 gene is polymorphic, linkage analysis showed that it was unlinked to the S-locus. The isolation of this S-RNase-binding protein in two different species and with four different S-RNase sequences as bait, strengthens its putative involvement in the SI response. Furthermore, comparison of the bait sequences used suggests that the SBP1 protein interacts with conserved sequences located between the HVa and HVb domains.

Keywords

S-RNase binding protein Gametophytic self-incompatibility RING finger protein Solanum chacoense 

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • Martin O’Brien
    • 1
  • Geneviève Major
    • 1
  • Sier-Ching Chantha
    • 1
  • Daniel P. Matton
    • 1
  1. 1.Institut de Recherche en Biologie Végétale, Département de Sciences BiologiquesUniversité de MontréalMontrealCanada

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