Expression Profile And Function Prediction Of Chicken Mirna Let-7a And Genetic Variation Analysis Of Target Genes ADIPOR2

let-7is one of the frist discovered, most abundant and highly conservedmiRNA cross species, which plays an important regulatory role in tumor cell proliferation,differentiation, adipogenesis and drug sensitivity. Previous Solexa sequencing analysis frommiRNA in the hypothalamus of1-day-old and36-weeks gushi chickens demonstrated thatlet-7is one of the most abundant and differential expression miRNA during development ofchicken hypothalamus. This suggests that the miRNAlet-7may play an important role in thedevelopment of the hypothalamus in chicken, but the current research about let-7function ofchicken has not yet been reported.In this study, the let-7expression profiles in13tissues in four stages of Gushi chicken werecharacterized by real-time quantitative PCR. The total107target genes were predicted bytwo kinds of algorithm overlap with GO and KEGG analysis.In addition, According to theresults of the bioinformatics analysis, we analyzed expression characteristics of target geneADIPOR2.PCR-RFLP ware used to detect SNPs of target gene ADIPOR2to elucidate theirassociations with chicken performance traits in an F2resource population of Gushi chickenand Anka broilers.Conclusions:1.let-7was widely expressed in the detection tissue and the expression in hypothalamusfrom the Solexa sequencing was consistent with those from real-time RT-PCR measures.Let-7was varied among different tissues，with most abundant in the brain tissues andvisceral tissues of two embryonic period. At1-day-old chickens, let-7was highly expressedin the hypothalamus and kidney, low expressed in the lung and moderate expressed in othertissues. Except for the lung the let-7expression was lower at the age of36weeks than that at1day.2.The total107target genes were predicted by two kinds of algorithm overlap with GOand KEGG analysis, the results showed that target genes were rich in the regulationbiological processes, especially in the minerals and phosphorus metabolism regulationprocess and significant existed in the regulatory pathway of focal adhesions, extracellularmatrix receptor interaction, the MAPK signaling pathway (P<0.01).3. ADIPOR2was comprehensive expressed in different tissues of different stages. Withthe growth and development, ADIPOR2and let-7expression in brain and muscular stomachshowed a trend of negative correlation, while consistent with each other in lung. In other10tissues, two gene expression not present obvious relevant.4.Significant associations for g.34490C>T mutation in intron2were found with liver weight and globulin (P<0.05), and additive effects on both traits were also significant(p<0.05); the g.35363T>C polymorphism is significantly associated with body weights at6,10and12weeks of age, which with significant dominant effect on significant carcasstraits(p<0.05). Both polymorphisms have no significant effects on fat-related traits.