Engineering ER-stress dependent non-conventional mRNA splicing

The endoplasmic reticulum (ER) protein folding capacity is balanced with the protein folding burden to prevent accumulation of un- or misfolded proteins. The ER membrane-resident kinase/RNase Ire1 maintains ER protein homeostasis through two fundamentally distinct processes. First, Ire1 can initiate a transcriptional response through a non-conventional mRNA splicing reaction to increase the ER folding capacity. Second, Ire1 can decrease the ER folding burden through selective mRNA decay. InSaccharomyces cerevisiae andSchizosaccharomyces pombe, the two Ire1 functions have been evolutionarily separated. Here, we show that the respective Ire1 orthologs have become specialized for their functional outputs by divergence of their RNase specificities. In addition, RNA structural features separate the splicing substrates from the decay substrates. Using these insights, we engineered anS. pombe Ire1 cleavage substrate into a splicing substrate, which confersS. pombe with both Ire1 functional outputs.
Source: eLife - Category: Biomedical Science Tags: Biochemistry and Chemical Biology Cell Biology Source Type: research