Discovery and characterization of miRNAs in mouse thymus responses to ionizing radiation by deep sequencing

To investigate the potential regulatory roles of microRNA (miRNA) in mouse response to ionizing radiation (IR)-induced thymus injury, miRNA expression profiles of mouse thymus with or without IR were analyzed using deep sequencing technology. Potential target candidates of the identified miRNA were predicted using RNAhybrid and miRanda. Differently expressed miRNA targets functional annotation and pathways were noted using Swiss-Prot, Gene Ontology (GO), Clusters of Orthologous Groups (COG), Kyoto Encyclopedia of Genes and Genomes (KEGG) and non-redundant (NR) databases. In this study, there were 112 differently expressed miRNAs identified, including 45 known mature and 67 novel miRNAs, which meanwhile contained 77 up-regulated and 35 down-regulated miRNAs. The results of quantitative RT-polymerase chain reaction (qRT-PCR) verification were in agreement with the sequencing analysis. And the target genes of miRNA were annotated. These results revealed the differences of miRNA expression, further extended the biological knowledge and greatly facilitated future studies on the function of miRNA in IR-induced thymus injury.

为探究微小核糖核酸（microRNA, miRNA）在小鼠应对电离辐射（ionizing radiation, IR）诱导的胸腺损伤中的潜在调控作用，本研究采用深度测序技术，对受电离辐射与未受电离辐射小鼠的胸腺组织miRNA表达谱进行了分析。利用RNAhybrid与miRanda工具，对鉴定得到的miRNA潜在靶标候选基因进行了预测。借助Swiss-Prot、基因本体（Gene Ontology, GO）、直系同源基因簇（Clusters of Orthologous Groups, COG）、京都基因与基因组百科全书（Kyoto Encyclopedia of Genes and Genomes, KEGG）及非冗余（non-redundant, NR）数据库，完成了差异表达miRNA靶标的功能注释与通路分析。本研究共鉴定出112个差异表达miRNA，其中包含45个已知成熟miRNA与67个全新miRNA；上调表达与下调表达的miRNA分别为77个和35个。定量反转录聚合酶链反应（quantitative RT-polymerase chain reaction, qRT-PCR）验证结果与测序分析结果相符，且已完成miRNA靶基因的注释工作。上述研究结果揭示了miRNA表达的差异特征，进一步拓展了相关生物学认知，为后续开展miRNA在电离辐射诱导胸腺损伤中的功能研究提供了重要支撑。