Dual roles of the serine/arginine-rich splicing factor SR45a in promoting and interacting with nuclear cap-binding complex to modulate the salt-stress response in Arabidopsis
Dual roles of the serine/arginine-rich splicing factor SR45a in promoting and interacting with nuclear cap-binding complex to modulate the salt-stress response in Arabidopsis
复制标题
富含丝氨酸/精氨酸的剪接因子 SR45a 在促进和与核帽结合复合物相互作用以调节拟南芥盐胁迫反应中的双重作用
DOI：
10.1111/nph.17175
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发表时间：
2021-02-10
期刊：
影响因子：
9.4
通讯作者：
Yan, Kang
中科院分区：
文献类型：
--
作者：
Li, Ying;Guo, Qianhuan;Yan, Kang
选择性剪接（alternative splicing，AS）是植物响应环境胁迫的一种重要的共转录调控机制。我们发现一个保守的富含丝氨酸/丝氨酸（serine/targetine-rich，SR）的类蛋白SR 45 a作为剪接体的一个组成部分，参与了拟南芥耐盐性的转录后调控。此外，SR 45 a是AS和信使RNA（mRNA）成熟的几个耐盐基因所必需的。盐胁迫诱导产生了两种SR 45 a的选择性剪接变异体，分别为全长SR 45 a-1a和截短的SR 45 a-1b。SR 45 a-1a和SR 45 a-1b过表达的植株对盐胁迫表现出高度敏感性，表明SR 45 a直接与介导盐胁迫反应的帽结合复合物（CBC）亚基帽结合蛋白20（CBP 20）相互作用。SR 45 a-1b不与其他剪接体成分结合，而是促进SR 45 a-1a与CBP 20的结合，从而介导盐胁迫信号转导途径。此外，SR 45 a和CBP 20的突变导致了不同的盐胁迫表型，这些结果表明SR 45 a-CBP 20作为一种调控复合物，通过调控机制来微调剪接因子，调节植物对盐胁迫的响应，特别是在胁迫条件下。
Alternative splicing (AS) is emerging as a critical co-transcriptional regulation for plants in response to environmental stresses. Although multiple splicing factors have been linked to the salt-sensitive signaling network, the molecular mechanism remains unclear.We discovered that a conserved serine/arginine-rich (SR)-like protein, SR45a, as a component of the spliceosome, was involved in post-transcriptional regulation of salinity tolerance in Arabidopsis thaliana. Furthermore, SR45a was required for the AS and messenger RNA (mRNA) maturation of several salt-tolerance genes. Two alternatively spliced variants of SR45a were induced by salt stress, full-length SR45a-1a and the truncated isoform SR45a-1b, respectively. Lines with overexpression of SR45a-1a and SR45a-1b exhibited hypersensitive to salt stress.Our data indicated that SR45a directly interacted with the cap-binding complex (CBC) subunit cap-binding protein 20 (CBP20) which mediated salt-stress responses. Instead of binding to other spliceosome components, SR45a-1b promoted the association of SR45a-1a with CBP20, therefore mediating salt-stress signal transduction pathways. Additionally, the mutations in SR45a and CBP20 led to different salt-stress phenotypes.Together, these results provide the evidence that SR45a-CBP20 acts as a regulatory complex to regulate the plant response to salt stress, through a regulatory mechanism to fine-tune the splicing factors, especially in stressful conditions.