An optimized assay for transcription factor NF-kappaB with dsDNA-coupled microplate

Area of Science:

• Biochemistry
• Molecular Biology
• Assay Development

Background:

• Electrophoretic Mobility Shift Assay (EMSA) is a common method for studying DNA-binding proteins (DBPs).
• However, EMSA is time-consuming and requires specialized equipment.
• There is a need for simpler, cost-effective, and EMSA-free methods for DBP analysis.

Purpose of the Study:

• To develop and optimize an EMSA-free assay using a double-stranded DNA (dsDNA)-coupled plate (dcPlate).
• To validate the optimized dcPlate assay for the detection of a key transcription factor, NF-kappaB.

Main Methods:

• Development of a cost-effective dsDNA-coupled plate (dcPlate) for DBP detection.
• Optimization of assay parameters including DNA probe concentration, incubation times, antibody concentrations, temperature, and colorimetric development time.
• Detection of NF-kappaB using the optimized dcPlate assay.

Main Results:

• Optimized dcPlate assay conditions significantly improved signal detection by threefold compared to unoptimized conditions.
• Established optimal parameters for NF-kappaB detection: 25 pmol/100 µL DNA probe, 90 min incubation for protein binding, 90 min for antibody binding, 25°C, and 30 min colorimetric development.
• Determined linear detection ranges for purified NF-kappaB p50 (0.59–75 ng/well) and cell nuclear extract (0.313–10 µg/well).

Conclusions:

• The optimized dcPlate assay provides an efficient and sensitive EMSA-free method for analyzing sequence-specific DNA-binding proteins.
• This assay is particularly effective for quantifying transcription factors like NF-kappaB in various biological samples.
• The dcPlate assay offers a valuable alternative for DBP analysis, simplifying workflows and reducing costs.