Conserved GU-rich elements mediate mRNA decay by binding to CUG-binding protein 1

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• The 3' untranslated region (UTR) of messenger RNA (mRNA) plays a crucial role in post-transcriptional gene regulation.
• Transcript stability and decay rates are critical determinants of protein levels.
• Identifying regulatory sequences and proteins involved in mRNA decay is essential for understanding gene expression.

Purpose of the Study:

• To identify conserved sequences in the 3' UTR of rapidly decaying transcripts in human T cells.
• To investigate the function of a newly identified sequence, the GU-rich element (GRE), in mRNA stability.
• To determine the protein factor responsible for mediating GRE-dependent mRNA decay.

Main Methods:

• Computational algorithms were used to identify conserved sequences in 3' UTRs.
• A tet-off reporter system was employed to assess the impact of GRE sequences on transcript stability.
• Supershift and immunoprecipitation assays were performed to identify GRE-binding proteins.
• siRNA-mediated knockdown was used to validate the role of the identified protein in mRNA decay.

Main Results:

• A consensus sequence, UGUUUGUUUGU (GU-rich element, GRE), was found to be enriched in short-lived transcripts.
• Insertion of GRE sequences into a stable beta-globin transcript conferred instability.
• CUG-binding protein 1 (CUGBP1) was identified as the primary GRE-binding protein in T cell extracts.
• Knockdown of CUGBP1 led to the stabilization of GRE-containing transcripts.

Conclusions:

• The GU-rich element (GRE) is a functional sequence that promotes mRNA decay.
• CUGBP1 is a key mediator of GRE-dependent mRNA decay.
• The GRE-CUGBP1 interaction provides a mechanism for coordinated mRNA decay in human T cells.