Sp1 was one of the first cellular transcription factors to be identified, cloned and characterized for its ability to bind to GC-boxes in regulatory promoter elements. Sp1 has always been described as a ubiquitous transcription factor that is required for the constitutive and inducible expression of a variety of genes, such as in the cell cycle and in mammalian development. Identification of new members of the Sp family, e.g. Sp2, Sp3, Sp4 and BTEB have redefined the understanding of Sp1-regulated genes. TransAM Sp1 and Sp1/Sp3 Kits contain antibodies specific for the active form of either Sp1 or Sp1/Sp3 when bound to its target DNA.
The TransAM™ advantage
Historically, transcription factor studies have been conducted using gelshift, Western blot and reporter plasmid transfections, which are time-consuming, do not allow for high-throughput and provide only semi-quantitative results. TransAM assays are up to 100 times more sensitive than gelshift techniques, and can be completed in less than 5 hours. Because TransAM is an ELISA-based assay*, there is no radioactivity, and the high-throughput stripwell format enables simultaneous screening of 1-96 samples. Inconsistencies due to variable reporter plasmid transfections are eliminated, along with the need to construct stable cell lines.
Why use TransAM?
- Up to 100-fold more sensitive than gelshift assays
- Eliminates the use of radioactivity and the need to run gels
- Results in less than five hours
- Colorimetric readout enables easy, quantitative analysis with spectrophotometry
- 96-stripwell format enables both high and low throughput
How TransAM™ Kits work
The TransAM format is perfect for assaying transcription factor binding to a consensus-binding site. TransAM Kits contain a 96-stripwell plate to which the consensus-binding site oligo has been immobilized. Activated nuclear extract is added to each well and the transcription factor of interest binds specifically to this bound oligonucleotide. A primary antibody specific for an epitope on the bound and active form of the transcription factor is then added followed by subsequent incubation with secondary antibody and Developing Solution to provide an easily quantified, sensitive colorimetric or chemiluminescent readout (Figure 1).
Figure 1: Flow chart of the TransAM process.
* Technology covered under EAT-filed patents and licensed to Active Motif. Use of TransAM in NFκB-related drug discovery may be covered under U.S. Patent No. 6,150,090 and require a license from Ariad Pharmaceuticals (Cambridge, MA, USA).


