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 在植物中，热应激诱导选择性剪接的变化，包括内含子保留；这些事件可以迅速改变蛋白质或下调蛋白质活性，产生非功能性亚型或诱导无义介导的mRNA衰变。亲核环素（CYPs）是多细胞真核生物剪接体复合体中的辅助蛋白。然而，植物CYPs是否参与前体mRNA剪接仍不清楚。在这里，我们发现拟南芥CYP18-1对于有效去除内含子是必需的，内含子是在萌发过程中因热应激而保留的。CYP18-1与第二步剪接因子（PRP18a、PRP22和SMP1）相互作用，并与热应激时的U2和U5小核RNA相关。CYP18-1与磷酸化PRP18a结合，CYP18-1浓度的增加与PRP18a去磷酸化的增加有关。此外，相互作用和原生质体转染实验显示，CYP18-1和PP2A型磷酸酶PP2A BʹȠ共同调节PRP18a去磷酸化。热应激下，qpr-RNA剪接和qprt-seqns是必需的。总的来说，我们揭示了CYP18-1激活PRP18去磷酸化的作用机制，并表明CYP18-1对于植物中保留内含子的有效剪接和对热应激的快速反应至关重要。
In plants, heat stress induces changes in alternative splicing, including intron retention; these events can rapidly alter proteins or downregulate protein activity, producing non-functional isoforms or inducing nonsense-mediated decay of mRNA. Nuclear cyclophilins (CYPs) are accessory proteins in the spliceosome complexes of multicellular eukaryotes. However, whether plant CYPs are involved in pre-mRNA splicing remains unknown. Here, we found that Arabidopsis thaliana CYP18-1 is necessary for the efficient removal of introns that are retained in response to heat stress during germination. CYP18-1 interacts with step II splicing factors (PRP18a, PRP22, and SMP1) and associates with the U2 and U5 small nuclear RNAs in response to heat stress. CYP18-1 binds to phospho-PRP18a, and increasing concentrations of CYP18-1 are associated with increasing dephosphorylation of PRP18a. Furthermore, interaction and protoplast transfection assays revealed that CYP18-1 and the PP2A-type phosphatase PP2A BʹȠ co-regulate PRP18a dephosphorylation. RNA-seq and RT-qPCR analysis confirmed that CYP18-1 is essential for splicing introns that are retained under heat stress. Overall, we reveal the mechanism of action by which CYP18-1 activates the dephosphorylation of PRP18 and show that CYP18-1 is crucial for the efficient splicing of retained introns and rapid responses to heat stress in plants. 【免责声明】图文来自网络，版权属于原作者，如有侵权或非授权发布之嫌，请联系我们，我们将及时更正、删除。转载目的在于促进信息交流，并不代表本公众号赞同其观点或对其内容真实性负责。 |
