REGULATION OF ALTERNATIVE SPLICING IN PLANTS BY LIGHT

EZEQUIEL PETRILLO; MARIA KALYNA; ANDREA BARTA; ALBERTO RODOLFO KORNBLIHTT

Krakovia - Polonia

Conferencia; First International EURASNET Conference on Alternative Splicing; 2008

Whereas the fraction of genes with alternative splicing is nearly70% in humans it is only 30% in Arabidopsis. Similarly, much more is known about alternative splicing regulationin mammalian cells compared to plants.With the aim of understanding the mechanisms that regulate alternativePETRILLO, EZEQUIELBECA POSDOC 10 Página 13 de 18splicing in plants, we studied the RUBISCO Activase and the RSp31 SR protein genes, whose alternative splicingpatterns vary depending on light conditions. In both genes, light exposure causes an increase in the proportionof the shorter mRNA isoforms. We found that light intensity, but not its quality, seems to be the factor that elicitschanges in splicing patterns. This is evidenced by realizing that blue or red light produce similar effects as whitelight and that different photoreceptor mutant plants behave as the WT in the alternative splicing response to whitelight. Consistently, drugs that inhibit the electronic photosynthetic transport abolish the effects of light on alternativesplicing. The involvement of a chloroplast signal was explored by using chloroplast signaling mutants. Furthermore,H2O2 treatment of seedlings in the dark duplicates the effects of light on alternative splicing, which suggests thatperoxides (or ROS) might act as signal intermediates. A correlation between the proportions of splicing isoforms withgene expression suggests a transcriptional regulation of alternative splicing. By using splicing reporter minigenesin BY-2 cells, we are investigating a possible coupling to transcription in plants.