, Xenopus/Amphibian,BP1 (1C4) Antibody

, Xenopus/Amphibian,BP1 (, Xenopus/Amphibian,-bo, Xenopus/Amphibian,-binding protein 1) is a transcription factor that regulates MHC class II genes by binding to a promoter element referred to as an , Xenopus/Amphibian, bo, Xenopus/Amphibian,. , Xenopus/Amphibian,BP1 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 e, Xenopus/Amphibian,pression 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 , Xenopus/Amphibian,BP1(S), which is the functionally active transcription factor. The isoform encoded by the unspliced mRNA, , Xenopus/Amphibian,BP1(U), is constitutively e, Xenopus/Amphibian,pressed, and thought to function as a negative feedback regulator of , Xenopus/Amphibian,BP1(S), which shuts off transcription of target genes during the recovery phase of ER stress.