RNAi Overview
In eukaryotic organisms, introduction of double-stranded RNA (dsRNA) induces sequence-specific degradation of cognate mRNA through a process known as RNA interference (RNAi) (1,2). RNAi has been proven a powerful tool for functional genomics research in model organisms (3,4).
dsRNA is processed in vivo into short (19-23 bp) fragments termed small interfering RNAs (siRNA) which function in concert with a group of intracellular proteins known as the RNA induced silencing complex (RISC). RISC is guided by siRNA to recognize and degrade the target mRNA.
For RNAi experiments in mammalian cells, only short siRNAs can be used for silencing because of a strong cytotoxic response to long dsRNA (5). siRNAs directed at specific gene targets can be chemically synthesized, transcribed in vitro or generated by enzymatic digestion of long dsRNA.
The figure below provides an overview of RNAi and highlights NEB's collection of products for in vitro transcription and RNA silencing.
References:
(1) Fire, A. et al. (1998) Nature 391, 806–811.
(2) McManus, M.T. and Sharp, P.A. (2002) Nature Reviews, Genetics 3, 737–747.
(3) Boutros, M. et al. (2004) Science 303, 832–835.
(4) Kamath, R.S. et al. (2003) Nature 421, 231–237.
(5) Elbashir, S. et al. (2001) Nature 411, 428–429.