Untemplated Oligoadenylation Promotes Degradation of RISC-Cleaved Transcripts

Authors

Fadia Ibrahim, University of Nebraska-LincolnFollow
Jennifer Rohr, University of Nebraska - Lincoln
Won-Joong Jeong, University of Nebraska - Lincoln
Jennifer Hesson, University of Nebraska - Lincoln
Heriberto D. Cerutti, University of Nebraska - LincolnFollow

Date of this Version

12-22-2006

Comments

Published in SCIENCE VOL 314 22 DECEMBER 2006. Copyright 2006. Used by permission. www.sciencemag.org

Abstract

In the best-characterized mechanism of RNAmediated silencing, small interfering RNAs (siRNAs), incorporated into the RNA-induced silencing complex (RISC), guide the endonucleolytic cleavage of complementary RNAs (1). In Drosophila melanogaster, these RISC-generated products are eventually degraded by exoribonucleases: Xrn1, a 5′-to-3′ exonuclease, and exosome, a 3′-to-5′ multisubunit exonuclease (2). Interestingly, in Arabidopsis thaliana and in mammals, an oligouridine or oligoadenine [oligo(U/A)] tail is added to the 5′ RNA fragments resulting from microRNA-directed cleavage (3). However, the biological role of this tail remains unclear.