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.

Target	XBP1
Reactivity	Human
Host	Mouse
Clonality	Monoclonal
Tested Applications	ELISA, WB
Recommended dilutions	ELISA: 1/10000, WB: 1/500 - 1/2000. Optimal dilutions/concentrations should be determined by the end user.
Immunogen	Purified recombinant fragment of human XBP1 expressed in E. Coli.
Isotype	IgG1
Conjugation	Unconjugated
Storage	Aliquot and store at -20 °C. Avoid repeated freeze/thaw cycles.
Molecular Weight	28 kDa
Swiss Prot	P17861
Buffer	Ascitic fluid containing 0.03% sodium azide.
Availability	Shipped within 5-10 working days.
Note	This product is for research use only.