Sequence Analysis & Identification Of Wheat Microrna

MicroRNAs(miRNAs), ranging in size from about 18 to 29 nucleotides, are a class of endogenous regulatory noncoding RNAs. MiRNAs play important role in gene expression mediation, for example, many miRNAs mediate the activity of transcription factors which are related with development. Now, plant miRNAs studies have been confirmed mainly to Arabidopsis and rice, two plant model species with fully sequenced genomes. wheat is one of the most important grain crops, the research on miRNAs in wheat are very important for the function of protein or other parts and the gene regulation in wheat.However, the genome of wheat is very huge and has not been sequenced completely yet. The related research on wheat miRNAs is very few. Considering the improtance of wheat research, the purpose of this study is to predict and identificate the miRNAs in wheat, which is necessary for the mechanism of miRNAs function in wheat.Firstly, select 10 sequences from the possible miRNAs whcih are cloned from wheat in our lab as the research object. And then, extract total RNAs from wheat leaves, stem and roots and enrich small-sized RNAs. Thirdly, certificate the possible small RNAs by Northern blotting, which shows 4 positive miRNAs sequences.Furthermore, it is necessary to analysis these 4 sequences whether they have the stem loop structure in their pri-miRNAs sequences. The Blast sofeware is used to search these 4 sequences in the wheat nucleotide sequence data. In the searching results which have EST sequence with the 4 sequences, choose 60-110 nt on the two sides of the positive sequences, and then, the DNAstructure program is used for the folding of these 4 positive sequences. Finally, dwindle the length of the pri-miRNAs to 60-220nt, and analysis the sequences again. As a result, the pri-miNAs which contain these 4 sequences all have the classical stem loop structure, which show that theses 4 sequences are new miRNAs sequences in wheat.