The Exosome Subunit Rrp44 Plays a Direct Role in RNA Substrate Recognition

Authors

Claudia Schneider, University of Edinburgh
James T. Anderson, Marquette UniversityFollow
David Tollervey, Marquette University

Document Type

Article

Language

eng

Format of Original

8 p.

Publication Date

7-20-2007

Publisher

Elsevier

Source Publication

Molecular Cell

Source ISSN

1097-2765

Abstract

The exosome plays key roles in RNA maturation and surveillance, but it is unclear how target RNAs are identified. We report the functional characterization of the yeast exosome component Rrp44, a member of the RNase II family. Recombinant Rrp44 and the purified TRAMP polyadenylation complex each specifically recognized tRNA_i^Met lacking a single m¹A₅₈ modification, even in the presence of a large excess of total tRNA. This tRNA is otherwise mature and functional in translation in vivo but is presumably subtly misfolded. Complete degradation of the hypomodified tRNA required both Rrp44 and the poly(A) polymerase activity of TRAMP. The intact exosome lacking only the catalytic activity of Rrp44 failed to degrade tRNA_i^Met, showing this to be a specific Rrp44 substrate. Recognition of hypomodified tRNA_i^Met by Rrp44 is genetically separable from its catalytic activity on other substrates, with the mutations mapping to distinct regions of the protein.

Comments

Accepted version. Cell Biology, Vol. 27, No. 2 (July 20, 2007): 324-331. DOI. © 2007 Elsevier Inc. Used with permission.

Recommended Citation

Schneider, Claudia; Anderson, James T.; and Tollervey, David, "The Exosome Subunit Rrp44 Plays a Direct Role in RNA Substrate Recognition" (2007). Biological Sciences Faculty Research and Publications. 439.
https://epublications.marquette.edu/bio_fac/439