Figure 1
From: The transcription factor X-box binding protein-1 in neurodegenerative diseases
Unconventional splicing of XBP-1. Xbp-1 gene is constitutively transcribed into a mature mRNA (hXBP-1Unspliced; panel A) The resulting mRNA (U, panel B) contains a 26 nucleotides long intron that is translated into an unstable and short 261 amino acids-long protein (U, panel C). Upon ER stress, IRE1 autoactivates and triggers an unconventional excision of the 26 nucleotides long intron. This splicing results in a lower molecular weight of the semi quantitative PCR fragment (S, panel B) yielded by primers a and b used for PCR (flanking the splicing region of XBP-1, see panel A) but results in a modified reading frame resulting in a longer protein (S, panel C).