Long npcRNAs in the control of Arabidopsis thaliana root development

ARIEL, FD; MERCHAN, F; GIACOMELLI, JI; THIEBAUT, F; MARIN, E; NUSSAUME, L; FERREIRA, P; CRESPI, M

Congreso; Chromatin: Structure & Function; 2011

ABCAM

Non protein coding RNAs (npcRNAs) are emerging as key players in the regulation of varied important cellular processes. Long npcRNA represent a class of riboregulators, which either act directly in this long form or are processed into shorter small si/miRNAs. Certain class of endogenous siRNAs derived from pairs of natural antisense transcripts (NATs) whereas other antisense RNAs may have specific localizations at tissular, cellular and sub-cellular levels and participate in epigenetic regulatory mechanisms. In our Lab, a bioinformatic approach identified 76 Arabidopsis thaliana npcRNAs including several siRNA precursors and antisense RNAs. Abiotic stress, such as phosphate starvation, drought or salt stress altered the accumulation of many of these npcRNAs(1). The behavior of a set of long npcRNAs in response to auxins, citokinins, ABA and stress indicates that they may be involved in root development. Besides, we have shown that certain siRNAs accumulate under the same conditions, suggesting an epigenetic link. Another long antisense RNA induced by phosphate starvation interacts with the overlapping transcript to generate a shorter RNA molecule. This RNA led, likely through RDR2, to the generation of a long double-stranded RNA that is not processed. The nucleotide sequence of this locus is conserved in brassicaceae and across Arabidopsis ecotypes. Overexpression of this locus led to a developmental phenotype, whereas mutant plants exhibit an abnormal behavior of the molecular markers of the response to phosphate starvation. This regulation may reveal a novel conserved mechanism mediated by an antisense RNA to control gene expression. We think that environmental control of long and small npcRNAs may mediate epigenetic mechanisms controlling root developmental plasticity.   (1) B. Ben Amor, et al.: Novel long non-protein coding RNAs involved in Arabidopsis differentiation and stress responses, Genome Res. (2009) 19, 57-69.