Research On The Differences Of Expression Of MiRNAs Among The Main Organs Between Fetus And Adult

microRNA(miRNA) are a class of about 21-25 nucleotide non-protein coding single-stranded small molecule RNA. By binding to imperfect complementary sites in the 3'untranslated regions(UTRs) of target mRNA and cutting, degradation of target mRNA or inhibition of target mRNA translation,miRNA repress the expression of target gene post transcriptional.A large number of studies have shown that, miRNA plays an extremely important role in regulation of gene expression in the process of cell differentiation, proliferation and apoptosis, growth and development of organisms, the formation of tumors and a variety of disease.Researches show that miRNA exhibit tissue-specific and developmental stage-specific expression. In order to explore the trend of miRNAs during growth and development of organisms and speculate the biological function of the relevant miRNAs,we test and analysis the expression of miRNAs in seven pairs of tissues (Liver, lung, large intestine, spleen, kidney, brain, heart ) which come from an adult and a fetal.We use the following experimental method to detect the expression level of miRNAs:isolation of small RNA,adding the poly(A)-tail, purified the poly(A)-tailed small RNA through phenol/chloroform extraction and ethanol precipitation, reverse transcription, RT-PCR and real-time quantitative PCR under a specific PCR system.After statistical analysis, we found that the expression quantity of total miRNAs in fetal tissue samples is higher than that in adult samples. At the same time, the top ten types of miRNA in expression level are dissimilar between the embryonic and adult tissues.The expression quantity of the same miRNA in the adult and the fetal sample's same tissue is also very different.Through the analysis of miRNAs'target gene prediction, we discovered that the expression of miRNA is synergistically. Many miRNAs by collaborative expressing regulate the growth of related or the growing key gene.We speculate that during embryonic development, miRNA plays an essential role in the growth and development. In comparison, the regulation of miRNA in normal adult body is not so significant than that in embryonic period.