A Role for LSM genes in the regulation of circaian rhythms.

SOLEDAD PEREZ SANTANGELO; ESTEFANÍA MANCINI; LAUREN J. FRANCEY; ARIEL CHERNOMORETZ; JOHN B. HOGENESCH; MARCELO J. YANOVSKY

Cordoba

Congreso; 16th International Congress on Photobiology; 2014

There is increasing evidence that alternative splicing is an important regulatory layer controlling circadian networks across eukaryotic organisms, but splicing factors regulating this process are largely unknown. Here we show that LSM genes encoding core components of the spliceosomal U6 SnRNP complex play a regulatory role in the control of circadian rhythms in plants and mammals. We found that the expression of several LSM genes in Arabidopsis plants or mice SCN is regulated by the circadian clock. Furthermore, mutations in LSM5 or LSM4 genes in Arabidopsis, or down-regulation of LSM5 or LSM3 expression in human cells, lengthens circadian period. Changes in expression and alternative splicing of some core clock genes were identified in Arabidopsis lsm mutants, but the precise molecular mechanism causing period lengthening remains to be identified. Genome-wide transcriptomic analysis of Arabidopsis lsm5 and lsm4 mutants revealed larger effects on alternative compared to constitutive splicing and, remarkably, no evidence of intron retention was observed in more than 95% of the approximately one hundred thousand splicing events evaluated in the strong loss of function lsm4 mutant allele. These findings support the idea that core components of the spliceosomal machinery play regulatory roles in RNA processing, and contribute to adjust physiological functions to dynamic environmental changes.