Developmentally and transgene regulated nuclear processing of primary transcripts of chalcone synthase A in petunia.
The introduction of chalcone synthase A transgenes into petunia plants can result in degradation of chalcone synthase A RNAs and loss of chalcone synthase, a process called cosuppression or post-transcriptional gene silencing. Here we show that the RNA degradation is associated with changes in premRNA processing, i.e. loss of tissue specificity in transcript cleavage patterns, accumulation of unspliced molecules, and use of template-specific secondary poly(A) sites. These changes can also be observed at a lower level in leaves but not flowers of nontransgenic petunias. Based on this, a model is presented of how transgenes may disturb the carefully evolved, developmentally controlled post-transcriptional regulation of chalcone synthase gene expression by influencing the survival rate of the endogenous and their own mRNA.
John Innes Centre, Norwich Research Park, Colney, Norwich, Norfolk NR4 7UH, UK. Michael.Metzlaff@aventis.com
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Metzlaff
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O'Dell
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Hellens
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Flavell
D000217:Acyltransferases / Q000235:genetics*; D002467:Cell Nucleus / Q000201:enzymology; D005786:Gene Expression Regulation; D009693:Nucleic Acid Hybridization; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics; D012326:RNA Splicing; D012333:RNA, Messenger / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019657:Solanaceae / Q000201:enzymology / Q000235:genetics*; D019076:Transgenes
D012333:RNA, Messenger; D000217:Acyltransferases; C020141:flavanone synthetase