Production of miRNAs starts with the transcription of genomic DNA into long primary transcripts called primiRNAs. The pri-miRNAs are subsequently cleaved by RNase III Drosha into shorter precursor transcriptswith hairpin structure calledpre-miRNAs. The pre-miRNAs are transported into the cytoplasm where they are processed by RNase III Dicer into ∼22 nt double-stranded miRNA molecules. Both strands of this duplex may become functional mature miRNAs.
Sequences of the miRNA oligonucleotides were obtained from the miRBase Release 21 (www.mirbase.org 我在这个网站中不能进行搜索，什么原因我也不清楚，推荐大家直接在Download中下载mature. fa，文件用记事本打开，输入miRNA名就可以直接搜索到成熟miRNA序列，各个物种都有).
