Figure 3.

Homeostatic regulation of splicing factor levels by AS‐NMD. Splicing activators and repressors can autoregulate their own protein levels through alternative splicing of their cognate pre‐mRNAs. When the splicing factor is present at high levels in the cell, it inhibits its own expression by stimulating the production of mRNA splice variants that will be targeted for degradation by NMD. Splicing activators stimulate the inclusion of stop codon exons, whereas splicing inhibitors repress the inclusion of a coding exon and hence generate PTC+ mRNAs. The relative levels of splicing activators and inhibitors further impact the alternative splicing of all other pre‐mRNAs in the cell.