What is Small interfering RNA?
[[Image:SiRNAvitro.gif|thumb|right|300px|Mediating RNA interference in cultured mammalian cells.]] '''Small interfering RNA''' ('''siRNA'''){{Efn|sometimes known as short interfering RNA or silencing RNA}} is a class of [[double-stranded RNA]] [[molecule]]s, 20-25 [[base pair]]s long. siRNA plays many roles, but it is most notable in the [[RNA interference]] (RNAi) pathway,<ref>Hannon G.J. & Rossi J.J. 2004. Unlocking the potential of the human genome with RNA interference. ''Nature'' '''431''' (7006): 371–378. [http://www.nature.com/nature/journal/v431/n7006/full/nature02870.html]</ref> where it interferes with the [[gene expression|expression]] of certain [[genes]]. Genes are only affected if they have [[nucleotide]] sequences complementary to those of the siRNA. siRNA functions by breaking down [[mRNA]] after [[transcription (genetics)|transcription]].<ref>[https://www.ncbi.nlm.nih.gov/pmc/articles/PMC309050/ RNA Interference: biology, mechanism, and applications<!-- Bot generated title -->]</ref> This prevents [[translation (genetics)|translation]] of the gene into [[protein]]. siRNA also acts in RNAi-related pathways, e.g., as an antiviral mechanism or in shaping the [[chromatin]] structure of a [[genome]]. The complexity of these pathways is only now being worked out. == Notes == {{reflist|group=lower-alpha}} == References == {{reflist}} [[Category:Genetic engineering]] [[Category:RNA]]