The 5?-3? exoribonuclease XRN4 regulates circadian rhythms in Arabidopsis thaliana.

CARENO D.A.; PEREZ-SANTANGELO S.; MORA-GARCÍA S.; YANOVSKY M.J.

Paraná

Congreso; LIV Reunión Anual de la Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular; 2018

Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular

Circadian rhythms allow organisms to adjust biological processes to occur at the most appropriate time of day. They are controlled by a complex gene network ?called the central oscillator?, in which genes interact mainly by transcriptional feedback loops, keeping an approximate 24h rhythm. Circadian rhythms are subject to many layers of regulation, such as transcriptional, epigenetic, post- transcriptional, and post-translational.Little is known about the mechanisms that act in the post-transcriptional layer. Among the different post-transcriptional mechanisms, in this work we focused on RNA stability and decay using the plant model organism Arabidopsis thaliana. We studied XRN4, the only 5?-3? cytoplasmic exoribonuclease described in Arabidopsis.We characterized different outputs of the clock in the loss-of-function xrn4-3 mutant. xrn4 showed a longer circadian period of leaf movement, a late flowering time phenotype, and no appreciable change in hypocotyl elongation. We also observed a deregulation of mRNA levels from some core oscillator genes. Finally, we studied the decay rates of the core oscillator genes by inhibiting transcription using cordycepin.This is the first exoribonuclease reported to be involved in circadian rhythm regulation. RNA decay stands out as a key component in the control of circadian rhythms.