Liu Shiping, Zhang Liang, Li Qibin, Zhao Ping, Duan Jun, Cheng Daojun, Xiang Zhonghuai, Xia Qingyou
The Key Sericultural Laboratory of Agricultural Ministry, College of Biotechnology, Southwest University, Chongqing 400715, PR China.
BMC Genomics. 2009 Sep 28;10:455. doi: 10.1186/1471-2164-10-455.
MicroRNAs (miRNAs) are expressed by a wide range of eukaryotic organisms, and function in diverse biological processes. Numerous miRNAs have been identified in Bombyx mori, but the temporal expression profiles of miRNAs corresponding to each stage transition over the entire life cycle of the silkworm remain to be established. To obtain a comprehensive overview of the correlation between miRNA expression and stage transitions, we performed a whole-life test and subsequent stage-by-stage examinations on nearly one hundred miRNAs in the silkworm.
Our results show that miRNAs display a wide variety of expression profiles over the whole life of the silkworm, including continuous expression from embryo to adult (miR-184), up-regulation over the entire life cycle (let-7 and miR-100), down-regulation over the entire life cycle (miR-124), expression associated with embryogenesis (miR-29 and miR-92), up-regulation from early 3rd instar to pupa (miR-275), and complementary pulses in expression between miR-34b and miR-275. Stage-by-stage examinations revealed further expression patterns, such as emergence at specific time-points during embryogenesis and up-regulation of miRNA groups in late embryos (miR-1 and bantam), expression associated with stage transition between instar and molt larval stages (miR-34b), expression associated with silk gland growth and spinning activity (miR-274), continuous high expression from the spinning larval to pupal and adult stages (miR-252 and miR-31a), a coordinate expression trough in day 3 pupae of both sexes (miR-10b and miR-281), up-regulation in pupal metamorphosis of both sexes (miR-29b), and down-regulation in pupal metamorphosis of both sexes (miR-275).
We present the full-scale expression profiles of miRNAs throughout the life cycle of Bombyx mori. The whole-life expression profile was further investigated via stage-by-stage analysis. Our data provide an important resource for more detailed functional analysis of miRNAs in this animal.
微小RNA（miRNA）由多种真核生物表达，并在多种生物学过程中发挥作用。家蚕中已鉴定出许多miRNA，但对应于家蚕整个生命周期中每个阶段转变的miRNA的时间表达谱仍有待确定。为了全面了解miRNA表达与阶段转变之间的相关性，我们对家蚕中近100种miRNA进行了全生命周期测试和随后的逐阶段检测。
我们的结果表明，miRNA在家蚕的整个生命周期中表现出多种多样的表达谱，包括从胚胎到成虫的持续表达（miR-184）、在整个生命周期中上调（let-7和miR-100）、在整个生命周期中下调（miR-124）、与胚胎发生相关的表达（miR-29和miR-92）、从三龄初期到蛹期上调（miR-275），以及miR-34b和miR-275之间表达的互补脉冲。逐阶段检测揭示了进一步的表达模式，例如在胚胎发生期间特定时间点出现以及晚期胚胎中miRNA组上调（miR-1和bantam）、与幼虫龄期和蜕皮阶段之间的阶段转变相关的表达（miR-34b）、与丝腺生长和吐丝活动相关的表达（miR-274）、从吐丝幼虫到蛹期和成虫期的持续高表达（miR-252和miR-31a）、两性蛹期第3天的协同表达低谷（miR-10b和miR-281）、两性蛹变态期上调（miR-29b）以及两性蛹变态期下调（miR-275）。
我们展示了家蚕整个生命周期中miRNA的全面表达谱。通过逐阶段分析进一步研究了全生命周期表达谱。我们的数据为该动物中miRNA更详细的功能分析提供了重要资源。
