REGULATION OF CIRCADIAN RHYTHMS BY A SM-LIKE FAMILY PROTEIN IN Arabidopsis thaliana

PEREZ SANTANGELO MS; SCHLAEN RG; YANOVSKY MJ.

Mendoza

Congreso; XLVIII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2012

Circadian rhythms allow organisms to time biological processes to the most appropriate phases of the day. There are many evidences that the regulation of alternative splicing contributes strongly to the adjustment of the circadian rhythms. Using a bioinformatics approach, we compared a list of genes regulated by the circadian oscillator at the mRNA level with a list of splicing factors and regulators in Arabidopsis thaliana. This comparison revealed that mRNAlevels of 83 genes from a list of 426 splicing related genes are regulated by the circadian clock. Leaf movement analysis in mutant plants for the majority of these genes did not affect clock function. Interestingly, a point mutation in the gene coding for LSm5, a protein of the Sm-Like family, showed a defect in clock function.We found that it has a 2.5hs longer period of circadian leaf movement than wild type plants and an early flowering phenotype in both, long and short day conditions. To verify that the observed phenotype in the period length is due to the point mutation in the Lsm5 gene, we complemented the mutant with the Lsm5 wild type gene restoring the wild type phenotype. Here we show a ?core? Sm like protein whose mRNA is clock regulated and the loss of function mutant affects the circadian clock, revealing a novel relationship between splicing and circadian rhythms.