| | Re: Differences between miRNA, shRNA, and siRNA?
Very interesting and "hot" topic
From the Sigma-Aldrich glossary:
Micro-RNAs are single-stranded RNAs of 22-nucleotides that are processed from ~70-nucleotide hairpin RNA precursors by the Rnase III nuclease, Dicer. Similar to siRNAs, miRNAs can silence gene activity through destruction of homologous mRNA in plants or blocking its translation in plants and animals.
shRNA or short hairpin RNA is an RNA molecule that contains a sense strand, antisense strand, and a short loop sequence between the sense and antisense fragments. Due to the complementarity of the sense and antisense fragments in their sequence, such RNA molecules tend to form hairpin-shaped double-stranded RNA (dsRNA). shRNA is cloned into a vector, allowing for expression by a pol III type promoter. The expressed shRNA is then exported into the cytoplasm where it is processed by dicer into siRNA which then get incorporated into the siRNA induced silencing complex (RISC).
Small Interfering RNA (siRNA)
Small Interfering RNA (siRNA) are 21-23 nucleotide double-stranded RNA molecules. Once incorporated into RISC they facilitate the cleavage and degradation of its recognized mRNA.
Of course there are plenty of review articles you may find useful, for example:
Cerutti H, Casas-Mollano JA. On the origin and functions of RNA-mediated silencing: from protists to man. Curr Genet. 2006 Aug;50(2):81-99.
Zhang B, Wang Q, Pan X. MicroRNAs and their regulatory roles in animals and plants. J Cell Physiol. 2007 Feb;210(2):279-89