Light, chromatin and alternative splicing

MICAELA GODOY HERZ; MA. GUILLERMINA KUBACZKA; EZEQUIEL PETRILLO; ALBERTO KORNBLIHTT

Congreso; SAIB, 51th Annual Meeting, Argentine Society for Biochemistry and Molecular Biology; 2015

Light is not only a source of energy but also a key regulator of plant physiological adaptations. We have previously shown that light/dark conditions affect several alternative splicing events including that of the Ser-Arg-rich splicing factor RS31. This led us to investigate whether chromatin modifications play a role in the regulation of alternative splicing by light. Increasing concentrations of trichostatin A (TSA), a drug that inhibits histone deacetylase activity and therefore increases histone acetylation, mimic the effect of light on At-RS31 alternative splicing in a dose-dependent manner. Increasing concentrations of camptothecin, a drug that inhibits topoisomerase I, mimic the effect of darkness on At-RS31 alternative splicing. Using Arabidopsis mutants defective in different histone modifying enzymes we found that the effect of light to dark transition on alternative splicing is strongly reduced in mutants that show higher levels of histone acetylation, such as the histone deacetylase hd1 or the histone methyltransferase kyp6. In contrast, an Arabidopsis mutant defective in a histone acetyltransferase, taf1, shows a stronger light to dark transition on alternative splicing compared to wild type plants. We are currently performing chromatin immunoprecipitation experiments to study changes in specific chromatin marks.