Morton Sarah U, Scherz Paul J, Cordes Kimberly R, Ivey Kathryn N, Stainier Didier Y R, Srivastava Deepak
Gladstone Institute of Cardiovascular Disease, Department of Pediatrics, University of California, San Francisco, CA 94158, USA.
Proc Natl Acad Sci U S A. 2008 Nov 18;105(46):17830-5. doi: 10.1073/pnas.0804673105. Epub 2008 Nov 12.
Organ patterning during embryonic development requires precise temporal and spatial regulation of protein activity. microRNAs (miRNAs), small noncoding RNAs that typically inhibit protein expression, are broadly important for proper development, but their individual functions during organogenesis are largely unknown. We report that miR-138 is expressed in specific domains in the zebrafish heart and is required to establish appropriate chamber-specific gene expression patterns. Disruption of miR-138 function led to ventricular expansion of gene expression normally restricted to the atrio-ventricular valve region and, ultimately, to disrupted ventricular cardiomyocyte morphology and cardiac function. Temporal-specific knockdown of miR-138 by antagomiRs showed miR-138 function was required during a discrete developmental window, 24-34 h post-fertilization (hpf). miR-138 functioned partially by repressing the retinoic acid synthesis enzyme, aldehyde dehydrogenase-1a2, in the ventricle. This activity was complemented by miR-138-mediated ventricular repression of the gene encoding versican (cspg2), which was positively regulated by retinoic-acid signaling. Our findings demonstrate that miR-138 helps establish discrete domains of gene expression during cardiac morphogenesis by targeting multiple members of a common pathway, and also establish the use of antagomiRs in fish for temporal knockdown of miRNA function.
胚胎发育过程中的器官模式形成需要对蛋白质活性进行精确的时空调节。微小RNA（miRNA）是一类通常抑制蛋白质表达的小型非编码RNA，对正常发育至关重要，但其在器官发生过程中的个体功能 largely unknown。我们报告称，miR-138在斑马鱼心脏的特定区域表达，是建立适当的腔室特异性基因表达模式所必需的。miR-138功能的破坏导致基因表达的心室扩张，而这些基因通常局限于房室瓣区域，最终导致心室心肌细胞形态和心脏功能紊乱。通过抗miR对miR-138进行时间特异性敲低表明，在受精后24-34小时（hpf）的离散发育窗口期间需要miR-138功能。miR-138部分通过抑制心室中的视黄酸合成酶醛脱氢酶-1a2发挥作用。这种活性通过miR-138介导的对编码多功能蛋白聚糖（cspg2）的基因的心室抑制得到补充，该基因受视黄酸信号的正向调节。我们的研究结果表明，miR-138通过靶向共同途径的多个成员，有助于在心脏形态发生过程中建立离散的基因表达域，同时也确立了在鱼类中使用抗miR进行miRNA功能的时间敲低。
