ï»?
è¿?/span>日,北京大学化学与分子工程学é™?/span>贾桂èŠ?/span>课题组在 ã€?/span>Molecular Plantã€?/span> ä¸?/span>在线发表了题ä¸?/span> â€?/span>Arabidopsis N6-methyladenosine reader CPSF30-L recognizes FUE signal to control polyadenylation site choice in liquid-like nuclear bodyâ€?/span> 的研究论æ–?/span>。该研究鉴定äº?/span>CPSF30-L为植物拟å�?/span>èŠ?/span>中的一个全æ–?/span>m6A结合蛋白ï¼?/span>揭示äº?/span>CPSF30-L依赖m6A识别促进ç›?/span>å�?/span>过程,以å�?/span>调控选择性多聚腺苷酸åŒ?/span>的分子机åˆ?/span>ã€?/span>
m6Aæ˜?/span>mRNAä¸?/span>丰度最é«?/span>çš?/span>化学修饰ï¼?/span>普遍存在于动物、植ç‰?/span>、真菌以å�?/span>RNA病毒之中ã€?/span>m6A可以分别在甲基转移酶复合物和去甲基酶的作用下è¢?/span>可逆地添加å’?/span>去除ï¼?/span>å¹?/span>ç”?/span>m6A结合蛋白识别å¹?/span>影响RNA代谢的各个方é�?/span>ã€?/span>尽管m6A相关蛋白在哺乳动物中已经被充分地鉴定及表征,ä½?/span>m6Aåœ?/span>植物生长发育ä¸?/span>以及RNA代谢ä¸?/span>çš?/span>调控功能研究ä»?/span>十分有限ã€?/span>
贾桂èŠ?/span>课题ç»?/span>致力于研ç©?/span>m6A在植物体中影响生长发育以及刺激响应的分子机制,在此前的研究中,该课题组绘制了植物拟å�?/span>èŠ?/span>和玉米的RNA修饰m6A全转å½?/span>图谱ï¼?/span>Nature Communications, 2014, 5, 5630ï¼?/span>Plant Physiology, 2020, 182, 332),鉴定了植物拟å�?/span>èŠ?/span>ä¸?/span>m6A去修饰酶ALKBH10Bå’?/span>第一ä¸?/span>m6A结合蛋白ECT2的生物功èƒ?/span>ï¼?/span>Plant Cell, 2018, 30, 968ï¼?/span>Plant Cell, 2017, 29, 2995ï¼?/span>,推动了植物中表è§?/span>转录ç»?/span>学的研究ã€?/span>不同çš?/span>m6A识别蛋白åœ?/span>mRNA的代谢过程中发挥着不同的调控功èƒ?/span>ï¼?/span> m6A结合结构åŸ?/span>YTH在拟å�?/span>èŠ?/span>中有13种同源蛋白之多,然而对于拟å�?/span>èŠ?/span>ä¸?/span>YTH结合家族蛋白的研究以å�?/span>调控机制相对较少ã€?/span>
该研究鉴定出拟南èŠ?/span>ä¸?/span>CPSF30-Lä¸?/span>m6A的结合蛋白,并且发现CPSF30-L可以通过m6A的结合能åŠ?/span>影响拟南èŠ?/span>的开花以å�?/span>ABA响应ã€?/span>亚细胞定位以å�?/span>FRAP实验表明CPSF30-L蛋白分布于细胞核中并发生液液相分离形成核体结构,并且CPSF30-Lçš?/span>m6A结合功能可以促进相分离的核体形成ã€?/span>
利用该课题组之前开å�?/span>çš?/span>甲醛交联-免疫共沉淀技术,åœ?/span>å…?/span>转录ç»?/span>水平上鉴定了CPSF30-L-RNA相互作用位点,揭ç¤?/span>äº?/span>CPSF30-L主要结合mRNAçš?/span>3'非翻译区 (3'UTR),并且倾向于结å�?/span>保守m6A基序以及聚腺苷酸化信å�?/span>â€?/span>UGUAã€?/span>GAAMHã€?/span>AAUAAA,暗ç¤?/span>CPSF30-L通过识别m6A修饰的聚腺苷酸化信号调控pre-mRNA 3'末端的加工过ç¨?/span>ã€?/span>随后,对野生型和CPSF30-Lçš?/span>T-DNA插入突变ä½?/span>cpsf30-l进行poly(A)位点测序分析ï¼?/span>发现CPSF30-L的破坏会整体影响polyï¼?/span>A)位点的选择,进一步的分析证实ï¼?/span>CPSF30-L通过识别 m6A修饰çš?/span>FUE聚腺苷酸化信号进è€?/span>精密控制polyï¼?/span>A)位点的选择ã€?/span>
ä¸?/span>拟南èŠ?/span>开花以å�?/span>ABA响应的三个基å›?/span>SOC1, RPN10å�?/span>FYVE1的转录本可以è¢?/span>m6A修饰且被CPSF30-L结合。相对于野生型而言ï¼?/span>åœ?/span>cpsf30-l中,SOC1, RPN10å�?/span>FYVE1çš?/span>pre-mRNAåœ?/span>3â€?/span>UTR加工过程中更倾向于远ç«?/span>poly(A)位点ï¼?/span>导致3â€?/span>UTR加长易被降解ï¼?/span>相应mRNA表达é‡?/span>下降,继而导è‡?/span>cpsf30-l突变体中呈现出晚花以å�?/span>ABA响应敏感的表åž?/span>(图一ï¼?/span>ã€?/span>这项研究发现了植物中m6A的全新功èƒ?/span>â€?/span>调控植物pre-mRNA聚腺苷酸化和植物相分离的分子机制ã€?/span>

图一. CPSF30-L 调控聚腺苷酸化的分子机制å›?/span>
北京大学化学与分子工程学院贾桂芳研究å‘?/span>为该论文的通讯作者,2017çº?/span>博士研究ç”?/span>生宋培哲,博士后杨军æ³?/span>为该论文çš?/span>共同第一作è€?/span>ï¼?/span>该研究得到了科技部、国家自然科学基金委、北京大学及北京分子科学国家研究中心çš?/span>资助ã€?/span>
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