dsRNAi or sdRNAi? - my first course (Apr/16/2007 )
through my reading in one site talking about applying RNAi in nematode worms, i came across this statement: " double-stranded RNA was substantially more effective than single strands at genetic interference"
why dsRNA is more effective, both single and double should do the same job !!
i'm a beginner in this field, thanx in advance
maybe you'll find this helpful!
thanx Krümel , i'll check it
any more comments !
There is a protein called Argonaute which (along with some other proteins) associates with ~21 base double stranded RNA, cleaving one strand and holding onto the other (called the "guide strand"). This complex of proteins with its single-stranded RNA then tests the RNA against other single-stranded RNAs and, when there is sufficient complementarity between the other RNA strand and the guide strand, the Argonaute protein cleaves the other RNA strand. If there is too little complementarity to trigger cleavage, the protein complex can still suppress translation of the other RNA strand.
Only double-stranded RNA loads onto the catalytic Argonaute-containing protein complex. Single stranded RNA can act as antisense, triggering degradation of complementary RNA by recruiting the enzyme RNase-H, but does not load onto the Argonaute complex and behave as RNAi.
Keywords to check for more information: RNAi, siRNA, miRNA, Argonaute, RNase-H
I hope that helps.
i read somewhere that the preference of using dsRNAi has something to do with viruses...