Short-lived AUF1 p42-binding mRNAs of RANKL and BCL6 have two distinct instability elements each.

Area of Science:

• Molecular Biology
• Gene Expression Regulation

Background:

• RNA-binding proteins significantly influence gene expression by regulating mRNA stability.
• AU-rich element binding protein 1 (AUF1) is implicated in post-transcriptional gene regulation.

Purpose of the Study:

• To identify novel mRNA targets of AUF1 and understand its binding characteristics.
• To investigate the role of AUF1 in mRNA stability and identify instability determinants.

Main Methods:

• Utilized myc-tagged AUF1 p42 in mouse NIH/3T3 cells.
• Isolated RNA-protein complexes using anti-myc antibody beads.
• Analyzed bound mRNAs using Affymetrix microarrays and the ARED Organism database.

Main Results:

• Identified 508 potential AUF1 target mRNAs with at least 3-fold enrichment.
• Enriched mRNAs showed a higher prevalence of AU-rich elements (AREs) and higher ARE scores.
• Discovered that AUF1 binds to short U-rich sequences, not exclusively canonical AREs.
• Identified specific instability determinants in HES1, RANKL, and BCL6 mRNAs, some conserved across evolution.

Conclusions:

• AUF1 binds to a wide spectrum of mRNAs, influencing their stability.
• AUF1's binding is associated with U-rich sequences, but not limited to classical AREs.
• Specific sequence elements within coding and 3'UTR regions contribute to mRNA instability mediated by AUF1.