Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Identification of novel maize miRNAs by measuring the precision of precursor processing | Jiao et al. BMC Plant Biology 2011 11 141 http 1471-2229 11 141 BMC Plant Biology RESEARCH ARTICLE Open Access Identification of novel maize miRNAs by measuring the precision of precursor processing Yinping Jiao Weibin Songt Mei Zhangt and Jinsheng Lai Abstract Background miRNAs are known to play important regulatory roles throughout plant development. Until recently nearly all the miRNAs in maize were identified by comparative analysis to miRNAs sequences of other plant species such as rice and Arabidopsis. Results To find new miRNA in this important crop small RNAs from mixed tissues were sequenced resulting in over 15 million unique sequences. Our sequencing effort validated 23 of the 28 known maize miRNA families including 49 unique miRNAs. Using a newly established criterion based on the precision of miRNA processing from precursors we identified 66 novel miRNAs in maize. These miRNAs can be grouped into 58 families 54 of which have not been identified in any other species. Five new miRNAs were validated by northern blot. Moreover we found targets for 23 of the 66 new miRNAs. The targets of two of these newly identified miRNAs were confirmed by 5 RACE. Conclusion We have implemented a novel method of identifying miRNA by measuring the precision of miRNA processing from precursors. Using this method 66 novel miRNAs and 50 potential miRNAs have been identified in maize. Background MiRNAs are known to play crucial roles in the regulation of gene expression in plants 1 including functions such as leaf polarity auxin response floral identity flowering time and stress response 2-7 . MiRNAs are typically 21 nucleotides in length. In plants miRNA genes are transcribed by RNA polymerasell into primary miRNA transcripts pri-miRNA which can form imperfect stem-loop secondary structure 8 9 . Then the pri-miRNAs are trimmed and spliced into miRNA miRNA duplex by Dicer-like1 DCL1 with the help of dsRNA binding protein HYL1 and dsRNA methylase HEN1 1 .
