生物谷報道：在6月29日著名國際雜志Cell上發(fā)表的一篇文章中,，發(fā)布了一張microRNA表達圖譜,，該結果顯示，哺乳動物為數(shù)眾多的microRNA只是起源于少數(shù)幾個microRNA基因,，而且組織或細胞特異的microRNA很少,。
該圖譜對來自人類和嚙齒類的26種正常,、腫瘤組織的細胞的microRNA表達進行了定量測定。“他們掌握了一種極為有用的資源,，”Dartmouth醫(yī)學院Victor Ambros說（未參與實驗）,，他們在研究中收集的組織種類非常多，并對這些組織中的microRNA的特征進行了系統(tǒng)性分析,。 新繪制的microRNA表達圖譜含有許多關于microRNA結構,、序列、表達方式和進化的有用信息,。Ambros認為這是一個基本數(shù)據(jù)庫,，為研究發(fā)育和疾病有關的microRNA世界提供了重要線索。
microRNA是動物,、植物和病毒中普遍存在的非編碼小RNA,，通過干擾mRNA的功能調節(jié)基因表達?？蒲腥藛T已經鑒定出多種哺乳動物microRNA，但對這些microRNA中大多數(shù)的表達水平和特征都是未知的,。
洛克菲勒大學Pablo Landgraf率領的研究小組克隆并測序了256個哺乳動物小RNA數(shù)據(jù)庫中的30多萬個序列,，找到了大約400個在任何組織都表達的microRNA——比之前預期的要少,。約翰霍普金斯大學Joshua Mendell說，這個結果提示在其它研究中找到的幾個百microRNA是未知的,。
Landgraf等還發(fā)現(xiàn)他們測序的microRNA克隆中,，97％的來自不到300個microRNA。文章共同作者,、瑞士Basel大學Mihaela Zavolan認為許多microRNA在各種組織間是低背景水平表達的（low background level），現(xiàn)在不能確定這些“痕量”microRNA的功能,，但很有可能大多數(shù)microRNA的功能是不相關的,。他們還發(fā)現(xiàn)這些稀少的microRNA在物種間的保守性很差,。
研究人員發(fā)現(xiàn)組織或者細胞特異的microRNA種類很少，相反,，細胞系和組織之間的差異經常局限在一小部分普遍存在的microRNA的表達水平的變化,。Mendell說缺乏細胞,、組織特異的microRNA并不意味著microRNA沒有區(qū)分腫瘤起源、組織或細胞的作用,。真正重要的是一個給定樣本表達的所有microRNA。
此次研究只鑒別出33種新的哺乳動物microRNA,。“這真是一件重量級研究，”Ambros說,，意味著我們漸漸補全了哺乳動物microRNA的目錄，至少是豐富了主要器官和組織的microRNA,，還有可能某些功能重要的microRNA只在個別種類細胞中表達,，所以沒有被檢測到,。
Table 1. miRNAs Identified in This Study and Not Listed in miRBase (Release 9.1)
Table 1. miRNAs Identified in This Study and Not Listed in miRBase (Release 9.1)
Human miRNA Sequence Clone # Mouse miRNA
Sequence Clone # Rat miRNA Sequence Clone #
miR-872__FM AAGGUUACUUGUUAGUUCAGG 11 miR-872 AAGGUUACUUGUUAGUUCAGG 394 miR-872 AAGGUUACUUGUUAGUUCAGG 373
miR-879 AGAGGCUUAUAGCUCUAAGCC 33 miR-879 AGAGGCUUAUAGCUCUAAGCC 5
miR-8822 AGGAGAGAGUUAGCGCAUUAGU 1 miR-882a6 AUGGGAAUGUUAGAGCAUUAGC 0
miR-882b AUGGCAAUGUUAGAGCAUUAGC 0
miR-874 CUGCCCUGGCCCGAGGGACCGA 17 miR-874 CUGCCCUGGCCCGAGGGACCGA 2 miR-874 CUGCCCUGGCCCGAGGGACCGA 0
miR-877 GUAGAGGAGAUGGCGCAGGG 40 miR-877 GUAGAGGAGAUGGCGCAGGG 6 miR-877 GUAGAGGAGAUGGCGCAGGG 2
miR-297c3 AUGUAUGUGUGCAUGUACAUGU 16
| miR-743b4 GAAAGACAUCAUGCUGAAUAGA 8 | miR-743b7 GAAAGACACCAUACUGAAUAGA 0
| miR-883a UAACUGCAACAGCUCUCAGUAU 6
| miR-883b UAACUGCAACAUCUCUCAGUAU 1 | miR-883 UAACUGCAACAUCUCUCAGUAU 0
| miR-880 UACUCCAUCCUCUCUGAGUAGA 119 | miR-880 UACUCCAUUCAUUCUGAGUAGA 3
| miR-878 GCAUGACACCACACUGGGUAGA 22 | miR-878 GCAUGACACCAUACUGGGUAGA 1
| miR-874 AACUGUGUCUUUUCUGAAUAGA 60 | miR-881 AACUGUGGCAUUUCUGAAUAGA 0
miR-871__FM UAUUCAGAUUAGUGCCAGUCAUG 2 | miR-871 UAUUCAGAUUAGUGCCAGUCAUG 11 | miR-871 UAUUCAGAUUGGUGCCGGUCACA 0
| miR-8901 UACUUGGAAAGGCAUCAGUUG 10
| miR-888 UACUCAAAAAGCUGUCAGUCA 16
| miR-465d UAUUUAGAAUGGUACUGAUGUG 0
| miR-892b CACUGGCUCCUUUCUGGGUAGA 14 | miR-465c UAUUUAGAAUGGCGCUGAUCUG 42
| miR-891b UGCAACUUACCUGAGUCAUUGA 4
| miR-891a UGCAACGAACCUGAGCCACUGA 24
| miR-466f5 UACGUGUGUGUGCAUGUGCAUG 7
| miR-466e GAUGUGUGUGUACAUGUACAUA 1.5
| miR-466b GAUGUGUGUGUACAUGUACAUG 7
| miR-466b8 UAUGUGUGUGUGUAUGUCCAUG 1
| miR-466c GAUGUGUGUGUGCAUGUACAUA 11
| miR-466c UGUGAUGUGUGCAUGUACAUG 2
| miR-467e AUAAGUGUGAGCAUGUAUAUGU 125
| miR-466d UGUGUGUGCGUACAUGUACAUG 4
| miR-466g AUACAGACACAUGCACACACA 2
| miR-466h UGUGUGCAUGUGCUUGUGUGUA 4
miR-885 UCCAUUACACUACCCUGCCUCU 5
miR-887 GUGAACGGGCGCCAUCCCGAGG 3
miR-886 CGCGGGUGCUUACUGACCCUU 16
The predominantly cloned sequence and orthologs are indicated. Bars beside the name indicate clustered miRNAs.
[1] Part of the cluster-hsa-mir-888(6), epididymis-specific expression.
[2] Part of the cluster-mmu-mir-134(33), enriched in embryonic tissue.
[3] Part of the cluster-mmu-mir-297a-1(46).
[4] Part of the cluster-mmu-mir-463(19), epididymis (testis) enriched expression.
[5] Part of the cluster-mmu-mir-297a-3(43).
[6] Part of the cluster-rno-mir-134(41).
[7] Part of the cluster-rno-mir-463(12).
[8] Part of the cluster-rno-mir-297c(4); Abbreviations are as follows: FM: “from mouse”; the same miRNA sequence as in mouse was cloned but could not be found in the current human assembly.
原始出處:
Cell, Vol 129, 1401-1414, 29 June 2007
