3 replies to this topic

[bioforum]

http://www.protocol-...roRNA-and-RNAi/

[1009]

I am quite confused about the differences between the mechanisms by which (i) antisense oligonucleotides, (ii) long dsRNA, and (iii) short 21-23 dsRNA act on RNAs to affect gene expression in human cells.

I heard that 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 I should talk about the exogenous siRNA here? 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. In addtion, isn't miRNA as a definition a endogenous single-stranded RNA?

[ravibiosciences]

Hi, Your questions are really broad. I hope these links will at-least help you to find the answer. Yes, you are right, miRNA is endogenous single stranded RNA.


http://www.ncbi.nlm....pubmed/19389436


http://www.gene-quan...si-rna-2006.pdf


http://www.nature.co...rnai/index.html


Good luck

Edited by ravibiosciences, 15 February 2012 - 08:31 AM.

[Jon Moulton]

These might also help.

------------------------------

Kole R, Krainer AR, Altman S. RNA therapeutics: beyond RNA interference and antisense oligonucleotides. Nat Rev Drug Discov. 2012 Jan 20. doi: 10.1038/nrd3625. [Epub ahead of print]

http://www.nature.co...ll/nrd3625.html

------------------------------

Summerton J.  Morpholino, siRNA, and S-DNA Compared: Impact of Structure and Mechanism of Action on Off-Target Effects and Sequence Specificity.  Med Chem. 2007;7(7):651-660
http://www.benthamdi...00007/0003R.SGM