The electrophoretic mobility shift assay (EMSA, gel shift, gel retardation) is a relatively simple and sensitive method to investigate protein:DNA interactions. These oligonucleotides contain consensus DNA-binding sites for individual sequence-specific transcription factors. The double-stranded oligonucleotides are designed with 5´ OH blunt ends, making them easily labeled to high specific activity with T4 polynucleotide kinase.
Applications include gel-shift assays and affinity chromatography.