Processing and Regulatory Impact of Endogenous siRNAs in Animals
from: Non-coding RNAs and Epigenetic Regulation of Gene Expression: Drivers of Natural Selection (Edited by: Kevin V. Morris). Caister Academic Press, U.K. (2012)
The complexity of an organism is driven by a positive balance between creative and destructive forces in the process of evolution. Small non-protein-coding RNAs play an instrumental role in both regulating gene expression (creative influence) as well as suppressing selfish genetic elements (defensive role). There are three main groups of small RNAs including microRNAs, endogenous siRNAs and piRNAs. MicroRNAs represent the most important gene regulatory small RNAs and act by tuning the expression level of eukaryotic mRNAs. Interestingly, endogenous siRNAs as well as piRNAs apparently serve both regulatory and defensive purposes. They suppress the expression of repetitive DNA elements but also influence the expression of protein coding genes. For endo-siRNAs, intriguing roles in epigenetic regulation are emerging. The multiple tasks of small RNAs are in line with a role as drivers of organismal complexity read more ...