Les séminaires ont lieu sur le Campus Montpellier SupAgro/INRA de La Gaillarde (2, place P. Viala Montpellier)
Mardi 16 avril 2013
hi 206 (Cœur d’Ecole) à 14h
How non-coding RNAs modulate root growth and development?
CNRS Institut des Sciences du Végétal, SPS Saclay Plant Sciences, Gif-sur-Yvette
Non-protein coding RNAs (npcRNA) represent an emerging class of riboregulators, which act either directly in a long form or are processed to shorter miRNA and siRNAs. Plant and animals use small RNAs (microRNAs and siRNAs) as guide for post-transcriptional mRNA cleavage or translational inhibition and also epigenetic regulation in the nucleus. In plants, miRNAs and trans-acting siRNA (tasiRNA) result from different biogenesis pathways but both interact with target transcripts to direct their cleavage. Interestingly, these small RNA molecules are able to traffick and transmit sequence-dependent information in plants including epigenetic patterns of regulation. We have performed genome-wide bioinformatic analysis of transcriptomic databases and identified many Arabidopsis long npcRNAs. Eleven npcRNAs were antisense to protein-coding mRNAs whereas certain corresponded to miRNA or siRNA precursors. The expression pattern of a set of long npcRNAs 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. Functional studies are ongoing to understand the regulatory mechanisms involving npcRNAs and their interacting RNA binding proteins in root growth. One example is miR169, a miRNA that controls root meristem size by modulating the action of NFY-A transcription factors in vascular tissues. A specific miR169 isoform is specialized in this regulatory node. Another npcRNA revealed unexpected relationships with alternative splicing during auxin-mediated regulation of root development. We think that environmental control of long and small npcRNAs may fine tune expression patterns of regulatory genes through interactions with RBPs to modulate developmental plasticity.
Contact : Philippe Nacry