PLOS genetics:中科院逆境中心朱健康研究组揭示SnRK2蛋白激酶调控

2017年4月18日，国际知名学术期刊《PLOS genetics》发表了中国科学院上海植物逆境生物学研究中心朱健康研究组题为“The SnRK2 kinases modulate miRNA accumulation in Arabidopsis”的研究论文。该项研究揭示了植物ABA信号转导和渗透胁迫的关键蛋白激酶SnRK2参与了miRNA生物合成的调控。

micrornA(miRNA)是是一种广泛存在于动植物体内的长度为20-24个核苷酸的非编码的小RNA。通过调控mRNA的剪切和翻译，miRNA参与了植物生长发育、胁迫应答等许多生物学过程。III型核糖核酸酶DCL1、锌指蛋白SE以及双链RNA结合蛋白HYL1是miRNA合成复合体的核心组分。已知植物激素脱落酸和渗透胁迫应答途径能够影响miRNA的积累，但详细的分子机制并不清楚。

逆境中心朱健康研究组发现植物激素脱落酸和渗透胁迫应答途径的核心组分SnRK2蛋白激酶能调控mirna合成途径中的核心组分，并调控miRNA的合成。在模式植物拟南芥中，SnRK2蛋白激酶家族共有10个成员(SnRK2.1-SnRK2.10)。其中，snrk2.2/2.3/2.6三突变体对ABA不敏感，而缺失所有SnRK2成员的snrk2十突变体缺乏适应渗透胁迫的能力，对渗透胁迫敏感。朱健康研究组发现snrk2.2/2.3/2.6突变体中，miR160等miRNA的含量降低，对应的miRNA的前体(pri-miRNA)以及靶基因表达增加。在snrk2三突变体和十突变体中HYL1蛋白含量降低。进一步的研究表明HYL1和SE蛋白可能是SnRK2蛋白激酶的磷酸化底物 。该研究发现了SnRK2蛋白激酶在miRNA合成过程中的重要作用，并初步揭示了ABA和渗透胁迫调控miRNA合成的分子机制。

原文链接：

The SnRK2 kinases modulate miRNA accumulation inArabidopsis

原文摘要：

MicroRNAs (miRNAs) regulate gene expression and play critical roles in growth and development as well as stress responses in eukaryotes. miRNA biogenesis in plants requires a processing complex that consists of the core components DICER-LIKE 1 (DCL1), SERRATE (SE) and HYPONASTIC LEAVES (HYL1). Here we show that inactivation of functionally redundant members of the SnRK2 kinases, which are the core components of abscisic acid (ABA) and osmotic stress signaling pathways, leads to reduction in miRNA accumulation under stress conditions. Further analysis revealed that the steady state level of HYL1 protein in plants under osmotic stress is dependent on the SnRK2 kinases. Additionally, our results suggest that the SnRK2 kinases physically associate with the miRNA processing components SE and HYL1 and can phosphorylate these proteins in vitro. These findings reveal an important role for the SnRK2 kinases in the regulation of miRNA accumulation and establish a mechanism by which ABA and osmotic stress signaling is linked to miRNA biogenesis.

doi:10.1371/journal.pgen.1006753

作者：朱健康