Western blot of mammalian whole cell extract transfected with HA epitope tagged human ATF3. ATF3 polyclonal antibody (Cat # PAB10024) detects a band ~31 KDa corresponding to recombinant human ATF3. Immunostaining using anti-HA epitope tag antibody confirms the composition of the recombinant band (not shown). The protein was transferred to nitrocellulose in 30 minutes using standard methods. After blocking with 5% goat serum and 0.5% non-fat milk in PBS, the membrane was probed with the primary antibody diluted 1 : 200 in 0.2X blocking buffer in PBS overnight at 4°C. Reaction was followed by washes and reaction with a 1 : 5000 dilution of IRDye™800 conjugated Gt-a-Rabbit IgG [H&L] for 30 min at room temperature. LICOR's Odyssey® Infrared Imaging System was used to scan and process the image. Other detection systems willyield similar results.
Activating transcription factor 3 is a member of the mammalian activation transcription factor/cAMP responsive element-binding (CREB) protein family of transcription factors. Multiple transcript variants encoding two different isoforms have been found for this gene. The longer isoform represses rather than activates transcription from promoters with ATF binding elements. The shorter isoform (deltaZip2) lacks the leucine zipper protein-dimerization motif and does not bind to DNA, and it stimulates transcription presumably by sequestering inhibitory co-factors away from the promoter. It is possible that alternative splicing of the ATF3 gene may be physiologically important in the regulation of target genes. [provided by RefSeq