Practice question

Electrophoretic Mobility Shift Assay, abbreviated EMSA, is formally known as electrophoretic mobility shift assay, also called gel mobility shift or gel retardation assay. Name directly describes underlying principle: association of protein with labeled DNA probe retards electrophoretic mobility in non-denaturing polyacrylamide gel, yielding shifted band. It is fundamental technique for demonstrating transcription factor binding, measuring affinity and assessing specificity with competitors. Reporter assay measures promoter activity via reporter gene, trap assay implies different purpose. Correct expansion is essential terminology for competitive examinations in molecular biology.