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来源 Nature 2008-10-30 9:06:55 ; G) ~' u- r+ s+ K
3 ]6 o+ F- K! j$ _Nature：MicroRNAs是后生动物的一个早期特征
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( u7 M6 R) o7 F5 M微RNA（MicroRNAs）是1993年在线虫中发现的抑制性小RNA分子，广泛分布在复杂动物中。人们普遍假设，它们是当动物形成双侧对称性（即动物身体结构复杂到有前部和后部以及上部和下部）时作为微调基因表达的一种方式而出现的。5 z K+ e1 q) S5 t9 b
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新的研究工作（这项工作是基于对三种“基底后生动物门”的代表动物（一种扁盘动物、一种海绵和一种海葵）及一种单细胞“领鞭毛虫”的总RNA内容所做测序进行的）表明，微RNA出现的时间要比人们以前所想的长得多。调控性微RNA通道似乎是在后生动物演化过程中非常早的时候出现的——是当多细胞生命方式出现时出现的，尽管这种机制后来在一些生命分支中丢失了。（生物谷Bioon.com）
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Nature 455, 1193-1197 (30 October 2008) | doi:10.1038/nature07415( u" C3 s7 G. M8 h; Y1 ]6 U
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Early origins and evolution of microRNAs and Piwi-interacting RNAs in animals
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Andrew Grimson1,2, Mansi Srivastava4, Bryony Fahey3, Ben J. Woodcroft3, H. Rosaria Chiang1,2, Nicole King4, Bernard M. Degnan3, Daniel S. Rokhsar4,5 & David P. Bartel1,27 O$ K: U+ U2 @8 p. U" a
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1 Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, Massachusetts 02142, USA2 e1 O9 l: G6 b
2 Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA8 C) c* v6 @5 i* r* I0 O: ]
3 School of Integrative Biology, University of Queensland, Brisbane 4072, Australia( V. q0 b; c2 d* |4 }- T0 R; s
4 Department of Molecular and Cell Biology and Center for Integrative Genomics, University of California at Berkeley, Berkeley, California 94720, USA
n4 {" L. p! a) W# O$ _) `+ U5 Department of Energy, Joint Genome Institute, Walnut Creek, California 94598, USA1 j8 B6 ]) x/ j. E2 w2 A
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In bilaterian animals, such as humans, flies and worms, hundreds of microRNAs (miRNAs), some conserved throughout bilaterian evolution, collectively regulate a substantial fraction of the transcriptome. In addition to miRNAs, other bilaterian small RNAs, known as Piwi-interacting RNAs (piRNAs), protect the genome from transposons. Here we identify small RNAs from animal phyla that diverged before the emergence of the Bilateria. The cnidarian Nematostella vectensis (starlet sea anemone), a close relative to the Bilateria, possesses an extensive repertoire of miRNA genes, two classes of piRNAs and a complement of proteins specific to small-RNA biology comparable to that of humans. The poriferan Amphimedon queenslandica (sponge), one of the simplest animals and a distant relative of the Bilateria, also possesses miRNAs, both classes of piRNAs and a full complement of the small-RNA machinery. Animal miRNA evolution seems to have been relatively dynamic, with precursor sizes and mature miRNA sequences differing greatly between poriferans, cnidarians and bilaterians. Nonetheless, miRNAs and piRNAs have been available as classes of riboregulators to shape gene expression throughout the evolution and radiation of animal phyla.. j% o9 I2 S4 C7 e$ w
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发表于 2011-4-19 23:12
