How long does a mobility shift assay take?

A mobility shift assay is electrophoretic separation of a protein–DNA or protein–RNA mixture on a polyacrylamide or agarose gel for a short period (about 1.5-2 hr for a 15- to 20-cm gel).

How is a supershift assay used in protein identification?

An antibody that recognizes the protein can be added to this mixture to create an even larger complex with a greater shift. This method is referred to as a supershift assay, and is used to unambiguously identify a protein present in the protein – nucleic acid complex.

How is the electrophoretic mobility shift assay ( EMSA ) used?

The gel electrophoresis mobility shift assay (EMSA) is used to detec t protein complexes with nucleic acids. It is the core technology underlying a wide range of qualitative and quantitative analyses for t he characterization of interacting systems.

When do you use the gel shift assay?

Gel shift assays are often performed in vitro concurrently with DNase footprinting, primer extension, and promoter-probe experiments when studying transcription initiation, DNA replication, DNA repair or RNA processing and maturation, as well as pre-mRNA splicing.

How is the electrophoretic mobility shift assay used?

This procedure can determine if a protein or mixture of proteins is capable of binding to a given DNA or RNA sequence, and can sometimes indicate if more than one protein molecule is involved in the binding complex.

Why is EMSA called a gel mobility shift assay?

EMSA is based on the principle that DNA–protein complexes are larger and move slowly when subjected to nondenaturing polyacrylamide gel electrophoresis (PAGE), compared to the unbound (free) DNA probe. Since the rate of DNA migration is shifted or retarded when bound to protein, the assay is also referred to as a gel shift or gel retardation assay.