Capitao Claudio, Shukla Neha, Wandrolova Aneta, Mittelsten Scheid Ortrun, Riha Karel
Gregor Mendel Institute of Molecular Plant Biology, Austrian Academy of Sciences, Vienna Biocenter, Vienna, Austria.
Central European Institute of Technology, Masaryk University, Brno, Czechia.
Front Plant Sci. 2018 Nov 6;9:1602. doi: 10.3389/fpls.2018.01602. eCollection 2018.
SMG7 proteins are evolutionary conserved across eukaryotes and primarily known for their function in nonsense mediated RNA decay (NMD). In contrast to other NMD factors, SMG7 proteins underwent independent expansions during evolution indicating their propensity to adopt novel functions. Here we characterized SMG7 and SMG7-like (SMG7L) paralogs in . SMG7 retained its role in NMD and additionally appears to have acquired another function in meiosis. We inactivated SMG7 by CRISPR/Cas9 mutagenesis and showed that, in contrast to our previous report, SMG7 is not an essential gene in Arabidopsis. Furthermore, our data indicate that the N-terminal phosphoserine-binding domain is required for both NMD and meiosis. Phenotypic analysis of SMG7 and SMG7L double mutants did not indicate any functional redundancy between the two genes, suggesting neofunctionalization of SMG7L. Finally, protein sequence comparison together with a phenotyping of T-DNA insertion mutants identified several conserved regions specific for SMG7 that may underlie its role in NMD and meiosis. This information provides a framework for deciphering the non-canonical functions of SMG7-family proteins.
SMG7蛋白在真核生物中具有进化保守性，主要因其在无义介导的RNA降解（NMD）中的功能而闻名。与其他NMD因子不同，SMG7蛋白在进化过程中经历了独立的扩增，这表明它们倾向于承担新功能。在这里，我们对[具体物种]中的SMG7和类SMG7（SMG7L）旁系同源物进行了表征。SMG7保留了其在NMD中的作用，此外似乎还在减数分裂中获得了另一种功能。我们通过CRISPR/Cas9诱变使SMG7失活，并表明，与我们之前的报告相反，SMG7在拟南芥中不是必需基因。此外，我们的数据表明，N端磷酸丝氨酸结合结构域对于NMD和减数分裂都是必需的。SMG7和SMG7L双突变体的表型分析并未表明这两个基因之间存在任何功能冗余，这表明SMG7L发生了新功能化。最后，蛋白质序列比较以及T-DNA插入突变体的表型分析确定了几个SMG7特有的保守区域，这些区域可能是其在NMD和减数分裂中发挥作用的基础。这些信息为解读SMG7家族蛋白的非经典功能提供了一个框架。
