Identification and functional outcome of mRNAs associated with RNA-binding protein TIA-1.
The RNA-binding protein TIA-1 (T-cell intracellular antigen 1) functions as a posttranscriptional regulator of gene expression and aggregates to form stress granules following cellular damage. TIA-1 was previously shown to bind mRNAs encoding tumor necrosis factor alpha (TNF-alpha) and cyclooxygenase 2 (COX-2), but TIA-1 target mRNAs have not been systematically identified. Here, immunoprecipitation (IP) of TIA-1-RNA complexes, followed by microarray-based identification and computational analysis of bound transcripts, was used to elucidate a common motif present among TIA-1 target mRNAs. The predicted TIA-1 motif was a U-rich, 30- to 37-nucleotide (nt)-long bipartite element forming loops of variable size and a bent stem. The TIA-1 motif was found in the TNF-alpha and COX-2 mRNAs and in 3,019 additional UniGene transcripts (approximately 3% of the UniGene database), localizing preferentially to the 3' untranslated region. The interactions between TIA-1 and target transcripts were validated by IP of endogenous mRNAs, followed by reverse transcription and PCR-mediated detection, and by pulldown of biotinylated RNAs, followed by Western blotting. Further studies using RNA interference revealed that TIA-1 repressed the translation of bound mRNAs. In summary, we report a signature motif present in mRNAs that associate with TIA-1 and provide support to the notion that TIA-1 represses the translation of target transcripts.
López de Silanes
Isabel
I
Laboratory of Cellular and Molecular Biology, Intramural Research Program, National Institute on Aging/NIH, 5600 Nathan Shock Drive, Baltimore, MD 21224, USA.
Galbán
Stefanie
S
Martindale
Jennifer L
JL
Yang
Xiaoling
X
Mazan-Mamczarz
Krystyna
K
Indig
Fred E
FE
Falco
Geppino
G
Zhan
Ming
M
Gorospe
Myriam
M
D001483:Base Sequence; D045744:Cell Line, Tumor; D019295:Computational Biology; D051546:Cyclooxygenase 2 / Q000235:genetics; D006801:Humans; D047468:Immunoprecipitation; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics
D012333:RNA, Messenger; D034741:RNA, Small Interfering; D016601:RNA-Binding Proteins; D014409:Tumor Necrosis Factor-alpha; C076751:TIAL1 protein, human; D051546:Cyclooxygenase 2