Abstract

Mobile Silencing RNAs

Attila Molnar, Chancellor’s Fellow, University of Edinburgh

RNA silencing is a nucleotide sequence-specific gene regulatory mechanism involved in development, stress responses and pathogenic defence. In flowering plants, RNA silencing is a non-cell-autonomous process. Spreading of RNA silencing across the plant has been recognized for nearly two decades, however, only recent reports from the Voinnet and Baulcombe labs have demonstrated beyond doubt that small non-coding RNAs [21-24 nucleotide (nt), sRNAs] are components of the mobile RNA silencing signal. The different size classes of sRNAs have distinct roles in RNA silencing. The 21nt sRNAs primarily mediate post-transcriptional silencing (PTGS) that involves mRNA cleavage/destabilization or translational inhibition in the cytoplasm. The 24 nt sRNAs are associated with nuclear events including RNA-dependent DNA methylation (RdDM) and histone modifications that can lead to transcriptional gene silencing (TGS). I will discuss the consequences of mobile sRNAs on target gene expression and its potential applications.