Guide RNA

Guide RNAs are cofactors for RNA editing in kinetoplastid protozoan parasites. They are localized in the mitochondria, where they function to direct insertion and/or deletion of uridylates (U) at specific sites of the pre-messenger RNA to generate the functional mRNA (1-5). The guide RNAs have three domains: (i) the 5′ region sequence is complementary to the substrate pre-mRNA and acts as an “anchor.” In vitro, this duplex formation is essential for editing to occur (6) . (ii) The central domain of the guide RNA contains the information necessary to insert and/or delete uridylates in the pre-mRNA to make the mature edited sequence, which is normally around 30–40 nucleotides in length. (iii) The 3′ end of the guide RNA is characterized by an oligo (U) tail that averages 12 nucleotides in length and is added post-transcriptionally; the function of this tail is unclear. With the development of an in vitro system for editing, a critical role in the specificity of editing for the cognate guide RNA has been established (6) .

References

1. R. Benne (1992) Mol. Biol. Rep. 16, 217–227. 

2. G. J. Arts, P. Sloof, and R. Benne (1995) Mol. Biochem. Parasitol. 73, 211–222. 

3. G. J. Arts, H. Vanderspek, D. Speijer, J. Vandenburg, H. Vansteeg, P. Sloof, and R. Benne (1993) EMBO J. 12, 1523–1532. 

4. K. Stuart, T. E. Allen, M. L. Kable, and S. Lawson (1997) Curr. Opin. Chem. Biol. 1, 340–346. 

5. H. Vanderspek, G. J. Arts, R. R. Zwaal, J. Vandenburg, P. Sloof, and R. Benne (1991) EMBO J. 10, 1217-1224.

6. E. M. Byrne, G. J. Connell, and L. Simpson (1996) EMBO J. 15, 6758–6765.