Electrophoretic mobility shift assay detects protein-nucleic acid binding by incubating a labeled DNA or RNA probe with purified protein or cell extract, then separating free probe from slower-migrating protein-probe complexes on a native gel. For cancer cells, primary neurons, mouse tumor samples, intestinal organoids, inflammatory macrophages, or drug-treated samples, EMSA can measure transcription-factor DNA binding or RNA-binding protein activity in extracts, but it does not directly measure transcription, protein expression, or chromatin occupancy in intact cells. Specificity is judged by competition with unlabeled wild-type probe, failure of mutated or unrelated competitors to compete, and antibody supershift or disruption when the binding protein identity must be confirmed.
Electrophoretic Mobility Shift Assay (EMSA)
Electrophoretic Mobility Shift Assay (EMSA) is an experimental method used to study the interaction between proteins and nucleic acids. By combining target proteins with fluorescently labeled nucleic acids, forming complexes, and then performing electrophoresis in a gel, differences in migration due to protein-nucleic acid binding can be observed. EMSA can be used to analyze DNA-binding proteins, study protein-RNA and DNA interactions, and explore gene regulatory mechanisms. This simple and sensitive technique is widely used in molecular biology and gene regulation research.
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