Retrotransposon insertion into the maize waxy gene results in tissue-specific RNA processing.
We previously reported that three alleles of the maize waxy (wx) gene were alternatively spliced as a result of the insertion of retrotransposons into intronic sequences. In addition, inefficient splicing of element sequences with the surrounding intron produced wild-type transcripts that presumably were responsible for the observed residual gene expression in the endosperm. In this study, we report that one of these alleles, wxG, has a tissue-specific phenotype with 30-fold more WX enzymatic activity in pollen than in the endosperm. Quantification of wxG-encoded transcripts in pollen and the endosperm demonstrates that this difference can be accounted for by tissue-specific differences in RNA processing. Specifically, there is approximately 30-fold more correctly spliced RNA in pollen than in the endosperm. Based on an analogy to similar examples of tissue-specific alternative splicing in animal systems, we hypothesize that the tissue-specific phenotype of the wxG allele may reflect differences in the concentration of splicing factors in these tissues.
Marillonnet
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Department of Botany, University of Georgia, Athens 30602, USA.
Wessler
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SR
D000483:Alleles; D017398:Alternative Splicing; D002874:Chromosome Mapping; D010940:Plant Proteins / Q000235:genetics*; D011058:Pollen / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000378:metabolism*; D018626:Retroelements; D012639:Seeds / Q000235:genetics / Q000378:metabolism; D013214:Starch Synthase / Q000235:genetics*; D014158:Transcription, Genetic; D003313:Zea mays / Q000235:genetics*
D010940:Plant Proteins; D018749:RNA, Plant; D018626:Retroelements; C060756:waxy protein, plant; D013214:Starch Synthase