TransAM® Kits are DNA-binding ELISAs that facilitate the study of transcription factor activation in mammalian tissue and cell extracts. Assays are available for over 40 different targets (see the list at right). Each kit includes a 96-stripwell plate in which multiple copies of a specific double-stranded oligonucleotide have been immobilized. When nuclear or whole-cell extract is added, activated transcription factor of interest binds the oligonucleotide at its consensus binding site and is quantified using the included antibody, which is specific for the bound, active form of the transcription factor being studied. For complete details, click the TransAM® Method tab below.
TransAM® CREB Transcription Factor ELISA Kits
TransAM CREB and TransAM pCREB Kits provide everything needed to study activated Cyclic AMP Response Element Binding (CREB), including a positive control extract. The TransAM CREB kit will detect total CREB, independent of phosphorylation state, in human, mouse, rat and monkey extracts, while the TransAM pCREB kit will detect CREB phosphorylated at Ser133 in human, mouse, rat and hamster extracts as well as phosphorylated CREM-1 and ATF-1. Click the CREB Info tab below for data and more information; kit manuals can be downloaded under the Documents tab.
CREB Transcription Factor Info
Cyclic AMP Response Element-Binding (CREB) protein is critical in a variety of cellular processes such as cell proliferation, differentiation and hormonal control of metabolic pathways. CREB is a member of a large family of structurally related transcription factors and binds as a homodimer to specific DNA sequences called the cAMP-response element (CRE) (5´-TGACGTCA-3´). CREB proteins activate the transcription of target genes in response to a diverse array of stimuli, such as the introduction of peptide hormones or growth factors, and neuronal activity. CREB activation is mediated by a variety of protein kinases, including protein kinase A (PKA), mitogen-activated protein kinases (MAPKs), and Ca+2 calmodulin-dependent protein kinases (CaMKs). These phosphorylate CREB at the Ser133 residue. Both phosphorylation at Ser133 and the binding of coactivator CBP (CREB-binding protein) are required to induce CREB-mediated transcription. Phosphorylation of CREB at Ser133 may play a role in the regulation of circadian rhythmicity. TransAM CREB and pCREB Kits contain antibody directed against CREB and phosphorylated CREB, respectively.
Figure 1: Measurement of phosphorylated CREB.
Human fibroblast WI-38 cells are stimulated with Forskolin for 30 minutes. Increasing amounts of nuclear cell extracts are assayed using the TransAM pCREB Kit.
The TransAM® transcription factor ELISA 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® transcription factor ELISAs?
- 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 at 450 nm
- 96-stripwell format enables both high and low throughput
How TransAM® transcription factor ELISAs work
The TransAM format is perfect for assaying transcription factor binding to a consen