Small-stranded insanity inside your cells

The Nature News Blog posted a fascinating video showing how RNA interference (RNAi) works within a cell. RNAi refers to the regulation of gene expression by short-length RNAs. So far as I understand it, there are a number of types of small stretches of RNA (e.g. siRNA, piRNA) that do not code for proteins but rather target other RNAs, and then latch onto them via proteins to ensure the other RNA's demise.  RNAi is implicated in expression of lots of genes, for instance HOTAIR is a long intergenic noncoding RNA that is itself located in the HOXC cluster but later acts to repress HOXD expression (Woo and Kingston 2007).

The video (there's also a slideshow) provides a stunning and digestible visual of what exactly is going on during this complex process. It's online and it's completely free (see links above), and so could be a valuable resource for teaching about this aspect of gene regulation.

Oh, the humanity. An Argonaute protein is guided by a small interfering RNA to where it will start rending a messenger RNA. From this great slideshow by Nature Reviews Genetics and Arkitek.

Some RNAi reviews
Czech, B., & Hannon, G. (2010). Small RNA sorting: matchmaking for Argonautes Nature Reviews Genetics, 12 (1), 19-31 DOI: 10.1038/nrg2916

Moss, E. (2001). RNA interference: It's a small RNA world Current Biology, 11 (19) DOI: 10.1016/S0960-9822(01)00467-5

Woo, C., & Kingston, R. (2007). HOTAIR Lifts Noncoding RNAs to New Levels Cell, 129 (7), 1257-1259 DOI: 10.1016/j.cell.2007.06.014

Anton Wutz (2011). RNA-Mediated Silencing Mechanisms in Mammalian Cells Progress in Molecular Biology and Translational Science, 101, 351-376 DOI: 10.1016/B978-0-12-387685-0.00011-1

UPDATE: The Journal of Experimental Zoology B has an entire issue dedicated to "RNA in Developmental Evolution."