Progress on the Mobile Silencing Signal of RNA Silencing

RNA silencing is a conserved eukaryotic pathway involved in suppression of gene expression via sequence-specific interactions that are mediated by 21-26nt RNA molecules. One of the most intriguing aspects of RNA silencing is that it is non-cell-autonomous, namely, in both plants and Caenorhabditis elegans it can be induced locally and then spread to distant sites throughout the organism. The systemic spread of silencing reflects the existence of a mobile silencing signal as an integral component of the RNA silencing pathway. The conduction nature of systemic silencing in plants and the possible candidates for the mobile silencing signal and so on were discussed.