Reporter assay using the beta-galactosidase (lacZ) gene. The lacZ gene is typically fused to the promoter of interest. Differential regulation of the promoter mediated by the TF is assessed by induction of the system and evaluation of lacZ expression. Bacteria expressing lacZ appear blue when grown on a X-gal medium. The assay is often performed using a plasmid borne construction on a lacZ(def) strain.

Target-specific mutation, as opposed to non-specific mutation. In the context of TF-binding sites, site-directed mutagenesis is typically used to establish/confirm the specific sequence and location of a site, often in tandem with EMSA. Different positions of a putative binding site are mutated to non-consensus (or random) bases and binding to the mutated site is evaluated through EMSA or other means. Often implemented only in conserved motif positions or serially through all positions of a site.

Visual inspection of promoter region to identify putative binding sites based on previous knowledge

A Western blot (also frequently called immunoblot) is a gel-based technique used to determine the presence of specific proteins in a sample by means of separation (through gel electrophoresis) and detection (using a protein-specific antibody). Less frequent than the equivalent RNA Northern blot, it is typically used in TF-binding site analysis to validate differential regulation of target genes.