Purified anti-XBP-1s

Xbp-1 (X-box binding protein 1) is a ubiquitously expressed 29 kD member of the CREB/ATF transcription factor family, and a mammalian homologue of the yeast transcription factor Hac1. Xbp-1 regulates MHC class II genes by binding to the X-box promoter motif and can also bind to the enhancer in T cell leukemia virus type I promoter to increase viral protein expression by binding the viral transactivator. This transcription factor is essential for hepatocyte differentiation and can be upregulated by ER stress, IL-6, and IL-4. The PAX5 transcription factor downregulates Xbp-1; downregulation has been shown to correlate with tumor progression in prostate cancer. The Poly6195 antibody recognizes the C-terminal region of human and rat Xbp-1 and has been shown to be useful for Western blotting.