The Improvement Of Purification Of MiRNA And The Identification And Expression Of MiRNA About Human Embryo Development

microRNA(miRNA) is the single strand small RNA that uncoding protein. It is known that 1/3 genes are regulate by miRNA, we need the profectional cloning methord for miRNA research because it is too small and has low abundance, sciencetists are focus on the new method, such as the approach designed by pro. QU from Zhongshan University and the approach designed by pro. ZHENG.The research improved the method of LMW RNA purification which is base on the method desigened by pro. ZHENG. Changed the concentration of the PEG and the precipitation time, we purified the LMW RNA from the total RNA successfully.miRNA is valuable for the embryo development especially for the early embryo development. Sciencsts found the miRNAs that are related to the embryo development and cell differentiation in c.elegan. We successfully got 8 small RNA sequences from the embryo of 45days, 55days and 90days as well as the cord blood using the improved method. After the BLAST and the second structure analysis, we identified that one of the small RNAs mightbe miRNA, named miR-X1 temporarily. Analysed by half quota RT-PCR miR-X1 could express truly, so that we identified miR-X1 was miRNA Initially. But for further identify, there should be Northern blot Evidence.Bioinformatics analysis showed that this miRNA is locate on intron of the forth chromatosome p16.3 of human, but we can't find its target gene.We found that this miRNA has high expression in the embryo before 60 days and cord blood, supposed that this miRNA might have the relationship with the cell differentiation and the development of human embryo, the result give the contribution to find the key miRNAs that control the development of human embryo as well as the cell differentiation.