Cell-free selection of RNA-binding proteins using in vitro compartmentalization

Area of Science:

• Molecular Biology
• Biotechnology
• Gene Regulation

Background:

• RNA-binding proteins (RBPs) are crucial for post-transcriptional gene expression control.
• Engineering RBPs with novel specificities offers powerful tools for gene expression research.
• Current molecular evolution methods like phage display have limitations in library diversity for RBP selection.

Purpose of the Study:

• To develop an improved method for selecting RNA-binding proteins (RBPs) with defined specificity.
• To overcome the limitations of existing molecular evolution techniques by increasing library diversity.
• To create a versatile platform for engineering RBPs for research and therapeutic applications.

Main Methods:

• Applied emulsion-based in vitro compartmentalization (IVC) to increase library diversity for RBP selection.
• Developed a genotype-phenotype linkage strategy by fusing RBPs to zinc finger proteins (ZFPs).
• Utilized a ZFP-RBP fusion protein that binds to a cognate DNA sequence upstream of its promoter.
• Selected RBPs based on their affinity for a biotinylated RNA bait after emulsion disruption.

Main Results:

• Demonstrated the effectiveness of the IVC-based method for selecting RBPs with defined specificity.
• Successfully linked RBP function (RNA binding) to its encoding DNA via the ZFP fusion.
• Showcased the ability to select RBPs with high affinity for specific RNA targets.
• Validated the approach for generating RBPs with new or improved RNA-binding properties.

Conclusions:

• The developed IVC method significantly enhances library diversity for RBP selection.
• The ZFP-RBP fusion system provides a robust mechanism for genotype-phenotype linkage.
• This approach enables the selection of RBPs with tailored specificity and affinity.
• The method holds promise for advancing tools to control and investigate gene expression pathways.