AUF1 facilitates microRNA-mediated gene silencing

• Published in: Nucleic acids research Vol. 45; no. 10; pp. 6064 - 6073
• Main Authors: Min, Kyung-Won, Jo, Myung Hyun, Shin, Soochul, Davila, Sylvia, Zealy, Richard W, Kang, Soo Im, Lloyd, Lawson T, Hohng, Sungchul, Yoon, Je-Hyun
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 02-06-2017
• Subjects: 3' Untranslated Regions - genetics; Alternative Splicing; Argonaute Proteins - metabolism; Base Sequence; Fluorescence Resonance Energy Transfer; Gene Silencing - physiology; HeLa Cells; Heterogeneous-Nuclear Ribonucleoprotein D - genetics; Humans; MicroRNAs - genetics; MicroRNAs - metabolism; Protein Binding; Protein Isoforms; Recombinant Proteins - metabolism; RNA; RNA Interference; RNA Stability - physiology; RNA, Small Interfering - genetics
• ISSN: 0305-1048; 1362-4962
• DOI: 10.1093/nar/gkx149

Eukaryotic mRNA decay is tightly modulated by RNA-binding proteins (RBPs) and microRNAs (miRNAs). RBP AU-binding factor 1 (AUF1) has four isoforms resulting from alternative splicing and is critical for miRNA-mediated gene silencing with a distinct preference of target miRNAs. Previously, we have shown that AUF1 facilitates miRNA loading to Argonaute 2 (AGO2), the catalytic component of the RNA-induced silencing complex. Here, we further demonstrate that depletion of AUF1 abolishes the global interaction of miRNAs and AGO2. Single-molecule analysis revealed that AUF1 slowed down assembly of AGO2-let-7b-mRNA complex unexpectedly. However, target mRNAs recognized by both miRNA and AUF1 are less abundant upon AUF1 overexpression implying that AUF1 is a decay-promoting factor influencing multiple steps in AGO2-miRNA-mediated mRNA decay. Our findings indicate that AUF1 functions in promoting miRNA-mediated mRNA decay globally.