We used computational algorithms to find conserved sequences in the 3′ untranslated region (UTR) of transcripts that exhibited rapid decay in primary human T cells and found that the consensus sequence UGUUUGUUUGU, which we have termed a GU-rich element (GRE), was enriched in short-lived transcripts. Using a tet-off reporter system, we showed that insertion of GRE-containing sequences from c-jun, jun B, or TNF receptor 1B, but not mutated GRE sequences, into the 3′UTR of a β-globin transcript conferred instability on the otherwise stable β-globin transcript. CUG-binding protein 1 (CUGBP1) was identified as the major GRE-binding activity in cytoplasmic extracts from primary human T cells based on supershift and immunoprecipitation assays. siRNA-mediated knockdown of CUGBP1 in HeLa cells caused stabilization of GRE-containing transcripts, suggesting that CUGBP1 is a mediator of GRE-dependent mRNA decay. Overall, our results suggest that the GRE mediates coordinated mRNA decay by binding to CUGBP1.
Bibliographical noteFunding Information:
This work was supported by grants AI49494 and AI52170 from the NIH to P.R.B. and by a research grant from the Minnesota Medical Foundation (to P.R.B. and I.A.V.). I.A.V. was funded through awards from the Minnesota Supercomputing Institute and the Lymphoma Research Foundation. N.M.T. was funded by the Pediatric Infectious Diseases Training Program (NIH grant T32 HD007381). O.L. was supported by a postdoctoral fellowship from the Swedish Research Council. D.F. and P.B.B. were supported by HL076779 and HL073719 from the NIH. We thank Dr. Ann-Bin Shyu and Dr. Thomas Cooper for providing plasmids.