SKU5-Similar3 gene could be alternatively spliced into two variants at an unreported splicing site in Arabidopsis

Alternative splicing largely enhanced the diversity of transcriptome and proteome in eukaryas. Along with technical development, more and more alternatively splicing was demonstrated. Here, we report an unexpected alternative splicing of SKU5-Similar 3 (SKS3) within a special splicing site in Arabidopsis. Based on bioinformatics database, SKS3 was predicted to be alternatively transcribed into two variants, SKS3.1 and SKS3.2, which encoded a GPI-anchored protein and a soluble secretory protein respectively. But, instead of SKS3.2, a novel variant, SKS3.3, which encoded a protein with transmembrane region at its C-terminus, was demonstrated based on our experimental data. Interestingly, it exhibited a different organ-specific expression pattern from SKS3.1, and its intron splicing site did not follow GT-AG rule or any reported rules.