最近的研究工作表明，微RNA（普遍存在的小型非編碼遺傳元素,，具有重要調(diào)控作用）在多細(xì)胞動(dòng)物復(fù)雜性的演化中起重要作用,。那么當(dāng)這些微RNA最初形成時(shí)其作用是什么呢？
對(duì)海生沙蠶（巖蟲）（Platynereis dumerilii）所做的一項(xiàng)深度測(cè)序研究及與其他兩側(cè)對(duì)稱動(dòng)物所做比較表明,，已知最古老的微RNA（即miR-100）最初在口腔周圍的神經(jīng)分泌細(xì)胞中是活躍的。其他高度保守的微RNA最初存在于特定組織和器官系統(tǒng)中,，如纖毛細(xì)胞,、神經(jīng)系統(tǒng)的部分地方,、肌肉組織和腸道。這項(xiàng)工作表明,，兩側(cè)對(duì)稱動(dòng)物的最后共同祖先已經(jīng)具有所有這些結(jié)構(gòu)了,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 463, 1084-1088 (25 February 2010) | doi:10.1038/nature08744
Ancient animal microRNAs and the evolution of tissue identity
Foteini Christodoulou1, Florian Raible1,2,4, Raju Tomer1, Oleg Simakov1, Kalliopi Trachana2, Sebastian Klaus1,4, Heidi Snyman1, Gregory J. Hannon3, Peer Bork2 & Detlev Arendt1
1 Developmental Biology Unit,
2 Computational Biology Unit, European Molecular Biology Laboratory, D-69117 Heidelberg, Germany
3 Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, New York 11724, USA
4 Present addresses: Max F. Perutz Laboratories, Campus Vienna Biocenter, Dr. Bohr-Gasse 9/4, A-1030 Vienna, Austria (F.R.); J. W. Goethe - Universit?t 5 Frankfurt Biologie-Campus, Siesmayerstrasse 70-72, D-60323 Frankfurt, Germany (S.K.).
6 Correspondence to: Detlev Arendt1 Correspondence and requests for materials should be addressed to D.A.
The spectacular escalation in complexity in early bilaterian evolution correlates with a strong increase in the number of microRNAs1, 2. To explore the link between the birth of ancient microRNAs and body plan evolution, we set out to determine the ancient sites of activity of conserved bilaterian microRNA families in a comparative approach. We reason that any specific localization shared between protostomes and deuterostomes (the two major superphyla of bilaterian animals) should probably reflect an ancient specificity of that microRNA in their last common ancestor. Here, we investigate the expression of conserved bilaterian microRNAs in Platynereis dumerilii, a protostome retaining ancestral bilaterian features3, 4, in Capitella, another marine annelid, in the sea urchin Strongylocentrotus, a deuterostome, and in sea anemone Nematostella, representing an outgroup to the bilaterians. Our comparative data indicate that the oldest known animal microRNA, miR-100, and the related miR-125 and let-7 were initially active in neurosecretory cells located around the mouth. Other sets of ancient microRNAs were first present in locomotor ciliated cells, specific brain centres, or, more broadly, one of four major organ systems: central nervous system, sensory tissue, musculature and gut. These findings reveal that microRNA evolution and the establishment of tissue identities were closely coupled in bilaterian evolution. Also, they outline a minimum set of cell types and tissues that existed in the protostome–deuterostome ancestor.
