Long npcRNAs in the epigenetic regulation of Arabidopsis thaliana root development

ARIEL, FD; ROMERO-BARRIOS, N; LATRASSE, D; BARDOU, F; BENHAMED, M; CRESPI, M

Suzhou

Conferencia; Epigenetics, Chromatin & Transcription; 2012

Cold Spring Harbor ASIA

Non-protein coding RNAs (ncRNAs) are emerging as key players in the regulation of varied important cellular processes. Long ncRNA represent a class of riboregulators, which either act directly in this long form or are processed into shorter small si/miRNAs, leading to mRNA cleavage, translational repression or epigenetic DNA/chromatin modification of their targets. In our Lab, a bioinformatic approach served to identify 76 Arabidopsis thaliana ncRNAs including several siRNA precursors and antisense RNAs. Abiotic stress, such as phosphate starvation, drought or salt stress altered the accumulation of many of these ncRNAs (1). The expression pattern of a set of long ncRNAs in response to phytohormones and environmental stresses suggested a link with root growth and development. Interestingly certain 24nt siRNAs derived from these loci accumulate under the same conditions, suggesting an epigenetic link. The overexpression of one auxin-responsive long ncRNA, npc34, in insertion promoter mutants and transgenic lines, leads to an acceleration of root growth and an altered response to gravity. Transcript levels of npc34 correlate with the expression of its neighbor gene PINOID (PID), a primary auxin-responsive gene involved in the phosphorylation of auxin efflux regulators. Furthermore, ChIP-qPCR experiments suggest that the npc34 over-accumulating lines have a modified chromatin status, exhibiting several modifications at the histone level, as well as in the spatial conformation of the chromatin. Our results suggest a direct implication of npc34 in PID expression regulation by chromatin remodeling, thus in the auxin control of root development. (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.