Expression and purification of recombinant NFI proteins for functional analysis

Area of Science:

• Molecular Biology
• Biochemistry
• Genetics

Background:

• Nuclear Factor I (NFI) is a transcription factor vital for signal transduction and development in eukaryotes.
• Recombinant NFI protein production is essential for detailed functional and structural analysis.

Purpose of the Study:

• To establish an efficient method for producing active, recombinant NFI proteins for further studies.
• To overcome challenges in expressing and purifying NFI isoforms from Escherichia coli.

Main Methods:

• Subcloning full-length NFI cDNAs into a pETM30 vector for expression in E. coli.
• Optimizing cell lysis and employing detergent (Tween 20) to improve purification yields.
• Developing a triple-helix affinity chromatography strategy involving Heparin-Sepharose, immobilized metal affinity, and glutathione affinity chromatography.

Main Results:

• Fusion proteins were overexpressed but primarily in insoluble form.
• Modified procedures significantly improved purification yields and protein activity.
• Heparin chromatography proved critical for obtaining active NFI proteins.
• Electrophoretic mobility shift assay (EMSA) and DNase I protection assays confirmed DNA-binding activity of the purified recombinant NFI proteins.

Conclusions:

• An effective purification protocol was established for recombinant NFI proteins.
• The developed method yields active NFI proteins capable of recognizing specific DNA sequences.
• This facilitates further investigation into NFI's roles in biological processes.