LIGHT-MEDIATED REGULATION OF ALTERNATIVE SPLICING AND TRANSCRIPTION ELONGATION IN PLANTS

GODOY HERZ, MICAELA; MA. GUILLERMINA KUBACZKA; ALBERTO KORNBLIHTT

Buenos Aires

Congreso; SAIB, LIII Reunión Annual Sociedad Argentina de Investigación Bioquímica y Biología Molecular.; 2017

Light is an environmental stimulus that regulates several biological processes in plants. Through the chloroplast, light regulates alternative splicing of a subset of genes. In this work, we aim to study the mechanism of light regulation of alternative splicing. We chose the Ser-Arg-rich splicing factor RS31 as a model. Treatment of plants with trichostatin A, a drug that suppresses histone deacetylase activity and therefore increases histone acetylation, mimics the effect of light on RS31 alternative splicing. TSA and light regulate alternative splicing of a subset of Arabidopsis transcripts, as shown in a high-resolution RT-PCR panel. The effect of light on alternative splicing involves changes in transcription elongation: treatment of plants with camptothecin, a drug that inhibits transcription elongation, mimics the effect of darkness on alternative splicing. In a mutant plant defective in the elongation factor TFIIS, the light/dark effect on alternative splicing is completely abolished. Finally, we performed measurements of transcription elongation rate and found that in light-treated plants transcription elongation is faster than in dark-treated plants along the RS31 gene. These results show that the effect of light on alternative splicing involves changes in transcription elongation.