This Article Full Text (PDF) Other Versions of this Article: MCB.01036-07v1 27/19/6806    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kim, H. S. Articles by Wilce, J. A. Search for Related Content PubMed PubMed Citation Articles by Kim, H. S. Articles by Wilce, J. A.

 Previous Article  |  Next Article 

Mol. Cell. Biol. doi:10.1128/MCB.01036-07
Copyright (c) 2007, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.

Elucidation of a C-Rich Signature Motif in Target mRNAs of RNA-Binding Protein TIAR

Department of Biochemistry and Molecular Biology, Monash University, Victoria 3800, Australia; Laboratory of Cellular and Molecular Biology, National Institute on Aging-Intramural Research Program, National Institutes of Health, Baltimore, MD 21228, USA; Research Resources Branch, National Institute on Aging-Intramural Research Program, National Institutes of Health, Baltimore, MD 21228, USA; Division of Rheumatology and Immunology, Harvard Medical School, Brigham and Women's Hospital, Boston, MA 02115, USA

^* To whom correspondence should be addressed. Email: myriam-gorospe{at}nih.gov.

	Abstract

The RNA-binding protein TIAR [related to TIA(T-cell intracellular antigen)-1] was shown to associate with subsets of mRNAs bearing U-rich sequences in their 3'-untranslated regions (UTRs). TIAR can function as a translational repressor, particularly in response to cytotoxic agents. Using unstressed colon cancer cells, collections of mRNAs associated with TIAR were isolated by immunoprecipitation (IP) of [TIAR-RNA] ribonucleoprotein (RNP) complexes, identified by microarray analysis, and used to elucidate a common signature motif present among TIAR target transcripts. The predicted TIAR motif was an unexpectedly cytosine-rich, 28- to 32-nucleotide long element forming a stem and a loop of variable size with an additional side loop. The ability of TIAR to bind an RNA oligonucleotide with a representative C-rich TIAR motif sequence was verified in vitro using surface plasmon resonance. By this analysis, TIAR containing 2 or 3 RNA recognition domains (TIAR12, TIAR123) showed low but significant binding to the C-rich sequence. In vivo, insertion of the C-rich motif into a heterologous reporter strongly suppressed its translation in cultured cells. Using this signature motif, an additional 2,500 UniGene targets were identified (3.4 % of the total UniGene database). A subset of specific mRNAs were validated by RNP IP analysis. Interestingly, in response to treatment with short-wavelength ultraviolet light (UVC), a stress agent causing DNA damage, each of these target mRNAs bearing C-rich motifs dissociated from TIAR. In turn, expression of the encoded proteins was elevated in a TIAR-dependent manner. In sum, we report the identification of a C-rich signature motif present in TIAR target mRNAs whose association with TIAR decreases following exposure to a stress-causing agent.