Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA.
Insect Biochem Mol Biol. 2012 Jun;42(6):381-95. doi: 10.1016/j.ibmb.2012.01.006. Epub 2012 Mar 1.
MicroRNAs (miRNAs) are a group of small RNAs involved in translation inhibition or mRNA degradation. Due to its large size, Manduca sexta has long been used as a model to study insect physiology and biochemistry. While transcriptome studies have greatly enriched our knowledge on M. sexta structural genes, little is known about posttranscriptional regulation by miRNAs in this lepidopteran species. We constructed four small RNA libraries from embryos, 4th instar feeding larvae, pupae, and adults, obtained 21 million reads of 18-31 nucleotides by Illumina sequencing, and found 163 conserved and 13 novel miRNAs. By searching the M. sexta genome assembly, we identified precursors of 82 conserved miRNAs, 76 of which had mapped reads in one or more of these libraries. After normalization, we compared numbers of miRNA and miRNA-star reads in these libraries and observed abundance changes during development. Interestingly, mse-miR-281-star, mse-miR-31-star, mse-miR-965-star, mse-miR-9a-star, mse-miR-9b-star, mse-miR-2a-star, mse-miR-92b-star and mse-miR-279c-star are either more abundant or maintained at similar levels compared to respective mature miRNA strand. Expression profiling of the first set of miRNAs provided insights to their possible involvement in developmental regulation. This study will aid in the annotation of miRNA genes in the genome.
微小 RNA（miRNA）是一类参与翻译抑制或 mRNA 降解的小 RNA。由于其体积较大，美洲蚕一直被用作研究昆虫生理学和生物化学的模型。虽然转录组研究极大地丰富了我们对 M. sexta 结构基因的了解，但对这种鳞翅目物种中 miRNA 的转录后调控知之甚少。我们从胚胎、4 龄期取食幼虫、蛹和成虫中构建了四个小 RNA 文库，通过 Illumina 测序获得了 2100 万个 18-31 个核苷酸的读段，并发现了 163 个保守 miRNA 和 13 个新 miRNA。通过搜索 M. sexta 基因组组装，我们鉴定了 82 个保守 miRNA 的前体，其中 76 个在前体中有一个或多个文库的映射读段。归一化后，我们比较了这些文库中 miRNA 和 miRNA-star 的读段数量，并观察到发育过程中的丰度变化。有趣的是，mse-miR-281-star、mse-miR-31-star、mse-miR-965-star、mse-miR-9a-star、mse-miR-9b-star、mse-miR-2a-star、mse-miR-92b-star 和 mse-miR-279c-star 要么比相应的成熟 miRNA 链更丰富，要么保持相似的水平。第一组 miRNA 的表达谱分析为它们在发育调控中的可能参与提供了线索。这项研究将有助于注释基因组中的 miRNA 基因。
