1. A conformational RNA zipper promotes intron ejection during non‐conventional XBP1 mRNA splicing
- Author
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Peschek, Jirka, Acosta-Alvear, Diego, Mendez, Aaron S, and Walter, Peter
- Subjects
Biochemistry and Cell Biology ,Bioinformatics and Computational Biology ,Biological Sciences ,Genetics ,Generic health relevance ,Animals ,Base Sequence ,Conserved Sequence ,DNA-Binding Proteins ,Endoplasmic Reticulum ,Endoribonucleases ,Humans ,Introns ,Nucleic Acid Conformation ,Protein Folding ,Protein Serine-Threonine Kinases ,RNA Splicing ,RNA ,Messenger ,Regulatory Factor X Transcription Factors ,Sequence Alignment ,Sequence Analysis ,DNA ,Transcription Factors ,Transcription ,Genetic ,Unfolded Protein Response ,X-Box Binding Protein 1 ,endoribonuclease ,ER stress ,RNA conformational change ,unfolded protein response ,XBP1 splicing ,Developmental Biology ,Biochemistry and cell biology - Abstract
The kinase/endonuclease IRE1 is the most conserved signal transducer of the unfolded protein response (UPR), an intracellular signaling network that monitors and regulates the protein folding capacity of the endoplasmic reticulum (ER). Upon sensing protein folding perturbations in the ER, IRE1 initiates the unconventional splicing of XBP1 mRNA culminating in the production of the transcription factor XBP1s, which expands the ER's protein folding capacity. We show that an RNA-intrinsic conformational change causes the intron of XBP1 mRNA to be ejected and the exons to zipper up into an extended stem, juxtaposing the RNA ends for ligation. These conformational rearrangements are important for XBP1 mRNA splicing in vivo. The features that point to such active participation of XBP1 mRNA in the splicing reaction are highly conserved throughout metazoan evolution, supporting their importance in orchestrating XBP1 mRNA processing with efficiency and fidelity.
- Published
- 2015