EXON SKIPPING INDUCED BY COLD STRESS IN A POTATO INVERTASE GENE TRANSCRIPT

We show that two invertase genes in potato, like most other plant inve rtase genes, include a very short second exon of 9 bp which encodes th e central three amino acids of a motif highly conserved in invertases of diverse origin, This mini-exon is one of the smallest known in plan ts and pre-mRNA from these genes may be susceptible to alternative spl icing, because of a potential requirement for specialized interaction with the splicing machinery to ensure correct processing for the produ ction of a mature mRNA, No evidence of aberrant post-transcriptional p rocessing was observed during normal invertase gene expression in pota to, The fidelity of post-transcriptional processing of the pre-mRNA fr om one of the genes was perturbed by cold stress, resulting in the del etion of the mini-exon from some transcripts, This alternative splicin g event occurred under cold stress in both leaf and stem, but was not induced by wounding, This adds an example of exon skipping and the ind uction of alternative processing by cold stress to the small number of transcripts which have been shown to exhibit alternative splicing in plants, The differential sensitivity of post-transcriptional processin g to cold stress observed for the two transcripts examined will permit further dissection of the nucleotide sequence requirements for their accurate splicing.