近日,，國際著名雜志PLoS ONE在線刊登了上海生化與細胞所張永蓮實驗室的最新研究成果“Identification and Characterization of a Novel Non-Coding RNA Involved in Sperm Maturation,”文章中，作者闡述了關(guān)于長鏈非編碼RNA以小RNA前體分子形式參與調(diào)節(jié)精子成熟的相關(guān)工作,。
小RNA分子近年來成為研究基因表達調(diào)控的熱門領(lǐng)域,，但其在精子附睪成熟過程中的作用的研究報道卻還很少。張永蓮組倪敏潔博士等利用大鼠附睪 cDNA 文庫篩選克隆到一個附睪特異的新長鏈非編碼RNA分子(HongrES2),。該RNA分子全長1.6kb,，有兩個exon，并且兩個exon來源于兩個不同的染色體,；具有類mRNA分子的5’端帽子和3’端polyA結(jié)構(gòu),，但卻沒有開放讀碼框。其3’端序列和另一個附睪特異編碼基因,，羧基酯酶ces7的3’端序列完全同源,，并能夠在細胞水平下調(diào)CES7的蛋白表達。
進一步的研究表明,，HongrES2能夠生成一個23bp的小RNA分子mil-Hongres2(microRNA like HongrES2),，而體內(nèi)外實驗都證明HongrES2對CES7的調(diào)節(jié)作用即為mil-hongres2對ces7 的直接靶向作用所致。另外該小RNA分子的生成量在正常生理水平很低,，受到附睪炎癥刺激后短時間內(nèi)激增,，表明其從前體到成熟體的過程受到嚴格調(diào)控；同時觀察到如果整體過表達其小分子成熟體,，大鼠精子的運動和獲能等精子附睪成熟過程均受到影響,。這些初期研究結(jié)果提示HongrES2以小分子調(diào)節(jié)RNA(small modulatory RNA，smRNA)的前體形式穩(wěn)定存在于大鼠附睪組織中,，參與維持附睪精子成熟所需特定的微環(huán)境,，而其是否會在附睪炎中發(fā)揮保衛(wèi)基因的作用還有待于后續(xù)的研究證實。該研究工作得到了中國科技部973項目的經(jīng)費支持,。（生物谷Bioon.com）
doi:10.1371/journal.pone.0026053
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Identification and Characterization of a Novel Non-Coding RNA Involved in Sperm Maturation
Min-Jie Ni1, Zhi-Hong Hu1, Qiang Liu1, Mo-Fang Liu2, Min-hua Lu2, Jin-Song Zhang1, Li Zhang1, Yong-Lian Zhang1,3*
The microRNA miR393 has been shown to play a role in plant development and in the stress response by targeting mRNAs that code for the auxin receptors in Arabidopsis. In this study, we verified that two rice auxin receptor gene homologs (OsTIR1 and OsAFB2) could be targeted by OsmiR393 (Os for Oryza sativa). Two new phenotypes (increased tillers and early flowering) and two previously observed phenotypes (reduced tolerance to salt and drought and hyposensitivity to auxin) were observed in the OsmiR393-overexpressing rice plants. The OsmiR393-overexpressing rice demonstrated hyposensitivity to synthetic auxin-analog treatments. These data indicated that the phenotypes of OsmiR393-overexpressing rice may be caused through hyposensitivity to the auxin signal by reduced expression of two auxin receptor genes (OsTIR1 and OsAFB2). The expression of an auxin transporter (OsAUX1) and a tillering inhibitor (OsTB1) were downregulated by overexpression of OsmiR393, which suggested that a gene chain from OsmiR393 to rice tillering may be from OsTIR1 and OsAFB2 to OsAUX1, which affected the transportation of auxin, then to OsTB1, which finally controlled tillering. The positive phenotypes (increased tillers and early flowering) and negative phenotypes (reduced tolerance to salt and hyposensitivity to auxin) of OsmiR393-overexpressing rice present a dilemma for molecular breeding.
