Format

Send to:

Choose Destination
See comment in PubMed Commons below
Nat Struct Mol Biol. 2009 Jan;16(1):56-62. doi: 10.1038/nsmb.1528. Epub 2008 Dec 7.

The exosome contains domains with specific endoribonuclease, exoribonuclease and cytoplasmic mRNA decay activities.

Author information

  • 1Department of Microbiology and Molecular Genetics, University of Texas Health Science Center-Houston, 6431 Fannin Street, MSB 1.212 Houston, Texas 77030, USA.

Abstract

The eukaryotic exosome is a ten-subunit 3' exoribonucleolytic complex responsible for many RNA-processing and RNA-degradation reactions. How the exosome accomplishes this is unknown. Rrp44 (also known as Dis3), a member of the RNase II family of enzymes, is the catalytic subunit of the exosome. We show that the PIN domain of Rrp44 has endoribonucleolytic activity. The PIN domain is preferentially active toward RNA with a 5' phosphate, suggesting coordination of 5' and 3' processing. We also show that the endonuclease activity is important in vivo. Furthermore, the essential exosome subunit Csl4 does not contain any domains that are required for viability, but its zinc-ribbon domain is required for exosome-mediated mRNA decay. These results suggest that specific exosome domains contribute to specific functions, and that different RNAs probably interact with the exosome differently. The combination of an endoRNase and an exoRNase activity seems to be a widespread feature of RNA-degrading machines.

Comment in

PMID:
19060898
[PubMed - indexed for MEDLINE]
PMCID:
PMC2615074
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Nature Publishing Group Icon for PubMed Central
    Loading ...
    Write to the Help Desk