Dikaya Varvara, Rojas-Murcia Nelson, Benstein Ruben Maximilian, Eiserhardt Wolf L, Schmid Markus
Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Sweden.
Department of Plant Biology, Linnean Center for Plant Biology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
PLoS One. 2025 Mar 26;20(3):e0318163. doi: 10.1371/journal.pone.0318163. eCollection 2025.
Plants are prone to genome duplications and tend to preserve multiple gene copies. This is also the case for the genes encoding the Sm proteins of Arabidopsis thaliana (L). The Sm proteins are best known for their roles in RNA processing such as pre-mRNA splicing and nonsense-mediated mRNA decay. In this study, we have taken a closer look at the phylogeny and differential regulation of the SmE-coding genes found in A. thaliana, PCP/SmE1, best known for its cold-sensitive phenotype, and its paralog, PCPL/SmE2. The phylogeny of the PCP homologs in the green lineage shows that SmE duplications happened multiple times independently in different plant clades and that the duplication that gave rise to PCP and PCPL occurred only in the Brassicaceae family. Our analysis revealed that A. thaliana PCP and PCPL proteins, which only differ in two amino acids, exhibit a very high level of functional conservation and can perform the same function in the cell. However, our results indicate that PCP is the prevailing copy of the two SmE genes in A. thaliana as it is more highly expressed and that the main difference between PCP and PCPL resides in their transcriptional regulation, which is strongly linked to intronic sequences. Our results provide insight into the complex mechanisms that underlie the differentiation of the paralogous gene expression as an adaptation to stress.
植物容易发生基因组加倍，并且倾向于保留多个基因拷贝。拟南芥（L.）中编码Sm蛋白的基因也是如此。Sm蛋白因其在RNA加工中的作用而最为人所知，例如前体mRNA剪接和无义介导的mRNA降解。在本研究中，我们仔细研究了拟南芥中发现的SmE编码基因、以其冷敏感表型而闻名的PCP/SmE1及其旁系同源基因PCPL/SmE2的系统发育和差异调控。绿色植物谱系中PCP同源物的系统发育表明，SmE加倍在不同植物分支中多次独立发生，并且产生PCP和PCPL的加倍仅发生在十字花科家族中。我们的分析表明，仅在两个氨基酸上存在差异的拟南芥PCP和PCPL蛋白表现出非常高的功能保守性，并且可以在细胞中执行相同的功能。然而，我们的结果表明，PCP是拟南芥中两个SmE基因的主要拷贝，因为它表达水平更高，并且PCP和PCPL之间的主要差异在于它们的转录调控，这与内含子序列密切相关。我们的结果为同源基因表达分化作为对压力的适应所依据的复杂机制提供了见解。
