XBP1 (NM_005080) Human Recombinant Protein

This gene encodes a transcription factor that regulates MHC class II genes by binding to a promoter element referred to as an X box. This gene product is a bZIP protein, which was also identified as a cellular transcription factor that binds to an enhancer in the promoter of the T cell leukemia virus type 1 promoter. It may increase expression of viral proteins by acting as the DNA binding partner of a viral transactivator. It has been found that upon accumulation of unfolded proteins in the endoplasmic reticulum (ER), the mRNA of this gene is processed to an active form by an unconventional splicing mechanism that is mediated by the endonuclease inositol-requiring enzyme 1 (IRE1) . The resulting loss of 26 nt from the spliced mRNA causes a frame-shift and an isoform XBP1 (S), which is the functionally active transcription factor. The isoform encoded by the unspliced mRNA, XBP1 (U), is constitutively expressed, and thought to function as a negative feedback regulator of XBP1 (S), which shuts off transcription of target genes during the recovery phase of ER stress. A pseudogene of XBP1 has been identified and localized to chromosome 5. [provided by RefSeq, Jul 2008]

Purified recombinant protein of -Human X-box binding protein 1 (XBP1), transcript variant 1, full length, with N-terminal GST and C-terminal His tag, expressed in E. coli, 50ug

Stable for 1 year at -20°C or below from date of shipment. For maximum recovery of product, centrifuge the original vial after thawing and opening the cap. For long-term storage, aliquot and store at -20°C or below. Avoid repeated freeze-thaw cycles.