In Signosis' TF filter plate assays, a specific biotin-labeled TF DNA binding sequence is mixed with nuclear extracts to allow formation of TF-DNA complexes. A filter plate is used to retain bound DNA probe and remove free probe. The bound pre-labeled DNA probe is then eluted from the filter and collected for quantitative analysis through DNA plate hybridization. The captured DNA probe is further detected with streptavidin-HRP. Luminescence is reported as relative light units (RLUs) on a microplate luminometer.