近日來(lái)自北京生命科學(xué)研究所的研究人員在《公共科學(xué)圖書館—遺傳學(xué)》（PLoS Genetics）雜志上發(fā)表題為“Transportin-SR Is Required for Proper Splicing of Resistance Genes and Plant Immunity”的文章,。
這篇文章的通訊作者是北京生命科學(xué)研究所的青年研究員張躍林博士,，其早年畢業(yè)于復(fù)旦大學(xué)遺傳學(xué)及遺傳工程專業(yè)，實(shí)驗(yàn)室的研究方向主要為先天性免疫和功能基因組學(xué),。博士研究生許少華為本文的第一作者,，參與此工作的還有張志斌、荊貝貝和丁金美以及University of British Columbia的Patrick Gannon,、徐芳和李昕教授,。
由植物抗性 (Resistance, R) 基因編碼的免疫受體在植物抗擊病原菌的免疫過(guò)程中發(fā)揮了重要作用。植物中很多R基因,，包括SNC1和RPS4都存在選擇性剪接,，然而植物體調(diào)控R基因剪接的機(jī)制目前還知之甚少。
在這篇文章中,，研究人員證實(shí)MOS14 (modifier of snc1-1, 14)的突變抑制了snc1植物中組成性激活的免疫反應(yīng),。圖位克隆和生物信息學(xué)分析顯示MOS14編碼了一個(gè)和動(dòng)物中Transportin-SR (TRN-SR) 存在序列相似性的蛋白。TRN-SR是importin-beta超家族的一個(gè)成員,，它負(fù)責(zé)serine-arginine rich (SR) 蛋白的入核轉(zhuǎn)運(yùn),，而SR蛋白在RNA代謝過(guò)程中發(fā)揮著重要作用。熒光共聚焦實(shí)驗(yàn)顯示MOS14定位在細(xì)胞核中,，酵母雙雜交顯示MOS14的C端可以和SR蛋白相互作用,，其N端可以和小G蛋白AtRAN1相互作用。SR蛋白在Col-0中定位于細(xì)胞核,，然而在mos14-1突變體中,，SR蛋白卻分散在整個(gè)細(xì)胞中。另外,，有幾個(gè)發(fā)生選擇性剪接的基因在mos14-1中的選擇性剪接模式發(fā)生了改變,，這些實(shí)驗(yàn)證明MOS14編碼了擬南芥中一個(gè)TRN-SR蛋白。
進(jìn)一步實(shí)驗(yàn)表明MOS14的突變導(dǎo)致了SNC1和RPS4這兩個(gè)R基因選擇性剪接模式的改變,，從而減弱了它們激活的免疫反應(yīng),。這些實(shí)驗(yàn)結(jié)果顯示，由MOS14介導(dǎo)的SR蛋白的入核對(duì)于這兩個(gè)R基因的正確剪接以及它們?cè)谥参镏薪閷?dǎo)的免疫反應(yīng)是非常重要的,。
此項(xiàng)研究為科技部和北京市科委資助課題,，在北京生命科學(xué)研究所完成。（生物谷Bioon.com）
生物谷推薦原文出處：
PLoS Genetics doi:10.1371/journal.pgen.1002159.g001
Transportin-SR Is Required for Proper Splicing of Resistance Genes and Plant Immunity
Shaohua Xu, Zhibin Zhang, Beibei Jing, Patrick Gannon, Jinmei Ding, Fang Xu, Xin Li, Yuelin Zhang
Transportin-SR (TRN-SR) is a member of the importin-β super-family that functions as the nuclear import receptor for serine-arginine rich (SR) proteins, which play diverse roles in RNA metabolism. Here we report the identification and cloning of mos14 (modifier of snc1-1, 14), a mutation that suppresses the immune responses conditioned by the auto-activated Resistance (R) protein snc1 (suppressor of npr1-1, constitutive 1). MOS14 encodes a nuclear protein with high similarity to previously characterized TRN-SR proteins in animals. Yeast two-hybrid assays showed that MOS14 interacts with AtRAN1 via its N-terminus and SR proteins via its C-terminus. In mos14-1, localization of several SR proteins to the nucleus was impaired, confirming that MOS14 functions as a TRN-SR. The mos14-1 mutation results in altered splicing patterns of SNC1 and another R gene RPS4 and compromised resistance mediated by snc1 and RPS4, suggesting that nuclear import of SR proteins by MOS14 is required for proper splicing of these two R genes and is important for their functions in plant immunity.
