Authors: Simon Schmidt Maria Lombardi Donald M Gardiner Michael Ayliffe Peter A Anderson
Publish Date: 2007/05/30
Volume: 115, Issue: 3, Pages: 373-382
Abstract
Alternative splicing is an important step in controlling gene expression and has been shown to occur for a number of plant disease resistance R genes The specific biological role of alternatively spliced transcripts from most R genes is unknown yet in two cases it is clear that functional disease resistance cannot be activated without them We report 12 splice isoforms of the M flax rust resistance gene a TIR–NBS–LRR class of R gene Collectively these isoforms are predicted to encode at least nine different polypeptide products only one of which is a full length peptide believed to confer functional M genespecific disease resistance An additional intron to that previously described was found in the 5′ untranslated region Splicing of this leader intron removes an upstream ORF μORF sequence In some transcripts the leader intron is retained and in this case we predict negligible translation initiation of the full length M geneencoding ORF The majority of the alternatively spliced isoforms of M would encode truncated TIR and TIR–NBS containing proteins Although the role of alternative splicing and the existence and function of the products they encode is still unclear the complexities of the splicing profile and the 5′ UTR of the M gene are likely to serve in mechanisms to regulate R protein levels
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