A collection of pre-mRNA splicing mutants in Arabidopsis thaliana

To investigate factors influencing pre-mRNA splicing in plants, we conducted a forward genetic screen using an alternatively-spliced GFP reporter gene in Arabidopsis thaliana. This effort generated a collection of eighteen mutants defective in various splicing-related proteins, many of which have not yet been characterized or recovered in any prior genetic screen in plants. The factors are predicted to act at different steps of the spliceosomal cycle, snRNP biogenesis pathway, transcription, and mRNA transport. Eleven of the mutants have been described in recent publications. Here we reveal the identity of the final seven mutants retrieved in the screen. We present new RNA-sequencing data and analyses of differential gene expression and alternative splicing patterns in a new mutant that is defective in CAP BINDING PROTEIN 80 (CBP80) and in several previously published mutants for which such information was not yet available. We discuss the cumulative findings and their implications for the regulation of pre-mRNA splicing efficiency and alternative splicing in plants. The mutant collection provides a unique resource for further studies on a coherent set of splicing factors and their roles in gene expression, alternative splicing and plant development.