A mutation in the AtPRP4 splicing factor gene suppresses seed development in Arabidopsis.

The spliceosome catalyzes alternative splicing of many genes in eucaryotic cells. This leads to the expression of distinct proteins. Components of the spliceosome are conserved in mammals and plants. Because splicing can be affected by environmental stress, we analyzed the regulation of splicing-related genes that encode small nuclear ribonucleoprotein particle (snRNP) proteins by the stress hormone abscisic acid (ABA). The transcript abundance of about 25 % of those genes was changed by at least 1.5-fold after addition of ABA. The U4/U6-specific snRNP gene AtPRP4 was strongly repressed by ABA. The homozygous knock-out of AtPRP4 resulted in the suppression of seed development suggesting that the gene product of this stress hormone-regulated gene is crucial for normal seed development.