shameless self promotion

don't expect anyone to really get what's going on here, but just posting this as evidence that i actually do real work. fruits of some of my labors after 3 years spent at Rockefeller...

Rrp17p Is a Eukaryotic Exonuclease Required for 5′ End Processing of Pre-60S Ribosomal RNA

Marlene Oeffinger, Daniel Zenklusen, Angelica Ferguson, Karen E Wei, Aziz El Hage, David Tollervey, Brian T Chait, Robert H Singer, Michael P Rout

Molecular Cell, Volume 36, Issue 5, 768-781, 11 December 2009

Summary

Ribosomal processing requires a series of endo- and exonucleolytic steps for the production of mature ribosomes, of which most have been described. To ensure ribosome synthesis, 3′ end formation of rRNA uses multiple nucleases acting in parallel; however, a similar parallel mechanism had not been described for 5′ end maturation. Here, we identify Rrp17p as a previously unidentified 5′–3′ exonuclease essential for ribosome biogenesis, functioning with Rat1p in a parallel processing pathway analogous to that of 3′ end formation. Rrp17p is required for efficient exonuclease digestion of the mature 5′ ends of 5.8SS and 25S rRNAs, contains a catalytic domain close to its N terminus, and is highly conserved among higher eukaryotes, being a member of a family of exonucleases. We show that Rrp17p binds late pre-60S ribosomes, accompanying them from the nucleolus to the nuclear periphery, and provide evidence for physical and functional links between late 60S subunit processing and export.

Figure 5.

Rrp17p Possesses a Highly Conserved Domain that Is Important for Its Catalytic Activity

i included this representative figure merely because i made all the mutant strains used and i'm shamelessly self-important...