Gu Jin, He Tao, Pei Yunfei, Li Fei, Wang Xiaowo, Zhang Jing, Zhang Xuegong, Li Yanda
Bioinformatics Division, Tsinghua National Laboratory for information Science and Technology, and Department of Automation, Tsinghua University, Beijing, 100084, China,
Mamm Genome. 2006 Oct;17(10):1033-41. doi: 10.1007/s00335-006-0007-9. Epub 2006 Oct 3.
MicroRNAs (miRNAs) are a class of approximately 22-nt small RNAs that regulate posttranscriptional gene expression. Thousands of expressed sequence tags (ESTs) have been identified by using upstream 2500-nt and downstream 4000-nt flanking sequences to BLAST in the dbEST database. The cotranscription of the miRNAs and their flanking sequences covered by the matched ESTs is verified by RT-PCR. It directly reveals that a large portion of mammalian intergenic miRNAs are first transcribed as long primary transcripts (pri-miRNAs). Also, the transcripts' ranges of tens of pri-miRNAs are predicted by the EST-extension method. We then extracted the tissue-specific expression information from the annotations of the matched ESTs and established the expression profile of the studied miRNAs for tens of tissues. This provided a new way to establish the expression profiles of miRNAs. Results show that the human brain, lung, liver, and eye and the mouse brain, eye, and mammary gland are tissues in which enriched numbers of miRNAs are expressed.
微小RNA（miRNA）是一类长度约为22个核苷酸的小RNA，可调控转录后基因表达。通过使用匹配EST的上游2500个核苷酸和下游4000个核苷酸侧翼序列在dbEST数据库中进行BLAST，已鉴定出数千个表达序列标签（EST）。通过RT-PCR验证了miRNA及其侧翼序列与匹配EST覆盖区域的共转录情况。这直接表明，大部分哺乳动物基因间miRNA最初转录为长的初级转录本（pri-miRNA）。此外，通过EST延伸法预测了数十个pri-miRNA的转录本范围。然后，我们从匹配EST的注释中提取了组织特异性表达信息，并建立了所研究miRNA在数十种组织中的表达谱。这为建立miRNA的表达谱提供了一种新方法。结果表明，人类的脑、肺、肝和眼睛以及小鼠的脑、眼睛和乳腺是表达丰富数量miRNA的组织。
