“组织器”组织的生成是胚胎学上的一个核心事件。这一类细胞通常被称为Spemann“组织器”，是由一个名为Nodal的变形生长因子β配体所产生的信号作用中的一个不对称现象在发育中的胚胎的背侧诱导生成的。 人们对这一不对称性知之甚少。现在，Martello等人发现，微RNA参与了这一过程。两个微RNA，即miR-15 和miR-16，通过在Nodal受体Acvr2a的表达上产生一个背侧偏向来限制该“组织器”的大小。微RNA是小的单链RNA分子，它们帮助调控基因表达，它们的很多不同功能才刚刚开始被人们全面研究。这项新的研究工作表明，微RNA在胚胎成形过程中的一个关键阶段发挥作用，它们是将β-catenin和Nodal信号作用联系起来的一个环节。
原始出处:
Nature 449, 183-188 (13 September 2007) | doi:10.1038/nature06100; Received 5 February 2007; Accepted 18 July 2007; Published online 29 August 2007
MicroRNA control of Nodal signalling
Graziano Martello1, Luca Zacchigna1, Masafumi Inui1, Marco Montagner1, Maddalena Adorno1, Anant Mamidi1, Leonardo Morsut1, Sandra Soligo1, Uyen Tran2, Sirio Dupont1, Michelangelo Cordenonsi1, Oliver Wessely2 & Stefano Piccolo1
Department of Histology, Microbiology and Medical Biotechnologies, Section of Histology and Embryology, University of Padua, viale Colombo 3, 35126 Padua, Italy
Departments of Cell Biology & Anatomy and Genetics, LSU Health Sciences Center, 1901 Perdido Street, New Orleans, Louisiana 70112, USA
Correspondence to: Stefano Piccolo1 Correspondence and requests for materials should be addressed to S.P. (Email: piccolo@bio.unipd.it).
MicroRNAs are crucial modulators of gene expression, yet their involvement as effectors of growth factor signalling is largely unknown. Ligands of the transforming growth factor- superfamily are essential for development and adult tissue homeostasis. In early Xenopus embryos, signalling by the transforming growth factor- ligand Nodal is crucial for the dorsal induction of the Spemann's organizer. Here we report that Xenopus laevis microRNAs miR-15 and miR-16 restrict the size of the organizer by targeting the Nodal type II receptor Acvr2a. Endogenous miR-15 and miR-16 are ventrally enriched as they are negatively regulated by the dorsal Wnt/-catenin pathway. These findings exemplify the relevance of microRNAs as regulators of early embryonic patterning acting at the crossroads of fundamental signalling cascades.
