University of Nordland, Faculty of Biosciences and Aquaculture, Postbox 1490, 8049 Bodø, Norway.
BMC Genomics. 2012 Jan 10;13:11. doi: 10.1186/1471-2164-13-11.
MicroRNAs (miRNAs) play a major role in animal ontogenesis. Size variants of miRNAs, isomiRs, are observed along with the main miRNA types, but their origin and possible biological role are uncovered yet. Developmental profiles of miRNAs have been reported in few fish species only and, to our knowledge, differential expressions of isomiRs have not yet been shown during fish development. Atlantic halibut, Hippoglossus hippoglossus L., undergoes dramatic metamorphosis during early development from symmetrical pelagic larval stage to unsymmetrical flatfish. No data exist on role of miRNAs in halibut metamorphosis.
miRNA profiling using SOLiD deep sequencing technology revealed a total of 199 conserved, one novel antisense, and one miRNA* mature form. Digital expression profiles of selected miRNAs were validated using reverse transcription quantitative PCR. We found developmental transition-specific miRNA expression. Expression of some miRNA* exceeded the guide strand miRNA. We revealed that nucleotide truncations and/or additions at the 3' end of mature miRNAs resulted in size variants showing differential expression patterns during the development in a number of miRNA families. We confirmed the presence of isomiRs by cloning and Sanger sequencing. Also, we found inverse relationship between expression levels of sense/antisense miRNAs during halibut development.
Developmental transitions during early development of Atlantic halibut are associated with expression of certain miRNA types. IsomiRs are abundant and often show differential expression during the development.
MicroRNAs（miRNAs）在动物个体发生中起着重要作用。miRNAs 的大小变体，即 isomiRs，与主要的 miRNA 类型一起被观察到，但它们的起源和可能的生物学功能尚未被揭示。目前仅在少数几种鱼类中报道了 miRNAs 的发育情况，据我们所知，在鱼类发育过程中尚未显示 isomiRs 的差异表达。大西洋比目鱼（Hippoglossus hippoglossus L.）在早期发育过程中经历了从对称的浮游幼体阶段到不对称的扁形鱼阶段的剧烈变态。目前还没有关于 miRNAs 在比目鱼变态过程中的作用的数据。
使用 SOLiD 深度测序技术进行 miRNA 分析共揭示了 199 种保守的、一种新的反义 miRNA 和一种 miRNA成熟形式。使用反转录定量 PCR 验证了所选 miRNA 的数字表达谱。我们发现了发育过渡特异性的 miRNA 表达。一些 miRNA的表达超过了指导链 miRNA。我们揭示了成熟 miRNA 的 3' 端核苷酸截断和/或添加导致了大小变体，这些变体在许多 miRNA 家族的发育过程中表现出不同的表达模式。我们通过克隆和 Sanger 测序证实了 isomiRs 的存在。此外，我们还发现了在大西洋比目鱼发育过程中 sense/antisense miRNAs 表达水平之间存在反相关关系。
大西洋比目鱼早期发育过程中的发育过渡与某些 miRNA 类型的表达有关。isomiRs 丰富，并且在发育过程中经常表现出差异表达。
