Question

In detail and understable terms, explain Electrophoretic mobility shift assay, its working principle and applications

Answer 1

Electrophoretic mobility shift assay in short EMSA or also termed as gel retardation assay is a technique used in electrophoresis to understand  Protein-DNA or protein-RNA interactions. This interactions help to determine if a protein or protein mixture has the ability of binding to a given DNA or RNA sequence. The principle lies in the movement of molecules in agarose or polyacralamide gel for some period of time. The speed at which molecules move through the gel pores is determined by size and charge, and least for their shape. In general, DNA moves faster in gel when it is not bound to a protein but a reduction in mobility shows that a complex has been formed between nucleic acid and proteins. This technique is used for detecting Protein-Nucleic Acid Interactions, DNA conformational changes, DNA bending. In this assay, radio actively labelled molecules can also be used for detection.