However, I have come across many papers where long piece of dsRNA (in both worms or plants) activate the RNAi pathway, in where the long dsRNA gets cleaved into siRNA (20-25nt) and ultimately cause SPECIFIC mRNA degradation via RISC. Does this mean the exogenous siRNA should be classified as a long dsRNA? But long dsRNA cause broad/global effect!! I am confused...
(In addition, both siRNA and miRNA are in definition a size of 19-25nt, where both have larger sized precursors. I do need clarification on these definitions. )
Lastly, isn't miRNA as a definition a endogenous single-stranded RNA?
Edited by 1009, 21 April 2010 - 04:48 PM.