ALTERNATIVE SPLICING REGULATION BY LIGHT/DARK TRANSITIONS IN Arabidopsis

EZEQUIEL PETRILLO; MICAELA A. GODOY HERZ; ALBERTO R. KORNBLIHTT

Congreso; SAIB - XLVII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2011

Light is not only a source of energy for green plants, it is also a source of information for the regulation of their growth, development and gene expression. The alternative splicing (AS) process is another layer of gene expression?s regulation that also contributes to the adjustment of an organism to its environment. Although, up to 90 % of human genes have at least two AS isoforms, this percentage is about 40 % for Arabidopsis thaliana. With the aim of understanding the biological relevance of AS isoforms, as well as deciphering the molecular mechanism regulating this process in plants, we analyzed about 100 AS events with a highresolution RT-PCR panel and found that ~ 40 % of them respond to light/dark transitions. We chose RSp31 transcriptional unit as a model to go further. Light exposure, increases the proportion of the functional mRNA isoform and a functional chloroplast with active photosynthetic electron transport is needed. Both H2O2 and sucrose mimic the effects of light on RSp31?s AS. This ?light effect? is also observed in roots, but only in those that have not been dissected from shoots before light exposure, suggesting that the signal is able to travel. Future work will be to evaluate whether this model of light signaling for AS regulation applies for the rest of the light responsive events under study and to gain insight into the signal?s nature.