Systematic characterization of branch point binding protein, splicing factor 1, gene family in plant development and stress responses

Abstract

Among eukaryotic organisms, the splicing of nuclear precursor messenger RNA (pre-mRNA) is a process of introns excision and sequentially joining of exons, leading multi-exonic genes to generate multiple splicing isoforms at transcription level. This process is carried out by a super-protein complex defined as spliceosome. Specifically, splicing factor 1/branchpoint binding protein (SF1/BBP) is a single protein that can bind to the intronic branchpoint sequence (BPS), connecting 5’ and 3’ splice site binding complexes during early spliceosome assembly. The molecular function of this protein has been extensively investigated in yeast, metazoan and mammals. However, their counterparts in plants are seldomly reported. To this end, we conducted a systematic characterization of SF1 gene family across plant lineage. In this work, a total of 92 sequences from 59 plant species were identified. Phylogenetic relationships of these sequences were constructed and subsequent bioinformatic analysis suggested that this family is likely originated from an ancient gene transposition duplication event. Most plant species were shown to maintain a single copy of this gene. Furthermore, an additional RNA binding motif (RRM) existed in most members of this gene family in comparison to their animal and yeast counterparts, indicating their potential role conserved in plant lineage. Our analysis presents general feature of gene and protein structure of this splicing factor family and will provide fundamental information for further functional studies in plants.