RNA Interactome Identification via RNA-BioID in Mouse Embryonic Fibroblasts

Area of Science:

• Molecular Biology
• Cell Biology
• Genetics

Background:

• Cytoplasmic mRNA localization is crucial for spatial gene expression across all organisms.
• Specific RNA sequences (zipcodes) in the 3'-untranslated region (3'-UTR) recruit RNA-binding proteins to direct mRNA transport.
• Existing methods like UV-cross-linking have limitations in identifying transient or indirect protein interactions with mRNA.

Purpose of the Study:

• To develop a novel in vivo proximity labeling method to identify the full spectrum of proteins associated with specific mRNAs.
• To overcome the limitations of current techniques in capturing transient and indirect RNA-protein interactions.
• To characterize the protein interactome of β-actin mRNA's 3'-UTR in mammalian fibroblasts.

Main Methods:

• Developed RNA-BioID, an in vivo proximity labeling technique.
• Tethered a BirA* biotin ligase-MS2 coat protein (MCP) fusion to MS2-tagged β-actin mRNA's 3'-UTR.
• Induced biotinylation of associated proteins in cells treated with biotin.
• Isolated biotinylated proteins using streptavidin beads and identified them via mass spectrometry.

Main Results:

• Successfully identified the β-actin mRNA 3'-UTR-interacting proteome in fibroblasts.
• Demonstrated the ability of RNA-BioID to capture both stable and transiently interacting proteins.
• Validated the method's effectiveness in identifying proteins directly or indirectly associated with mRNA localization elements.

Conclusions:

• RNA-BioID is a powerful tool for comprehensive identification of mRNA-associated proteins in vivo.
• This method advances the study of mRNA localization mechanisms and spatial gene regulation.
• The RNA-BioID protocol is adaptable for studying the interactome of any mRNA in mammalian cells.