Abstract：microRNA(miRNA) plays an important role for lipid metabolism. To find the potential miRNAs regulating fatty acid metabolism of mammary gland of goat, Databases and MFOLD were used for predicting miRNA and analyzing ΔG, respectively. And pri-miRNA were cloned for further study. Prediction results showed that 50 miRNAs including 13 identical miRNAs predicted by 3 databases and 37 identical miRNAs predicted by 2 databases were obtained through predicting 30 genes regulating fatty acid metabolism of goat by MicroCosm, TargertScan and PicTar on line. There were 4 and 2 different miRNA predicted targeting FASN(fatty acid synthase) and BTN1A1(goat butyrophilin, subfamily 1, member A1), respectively. And no miRNA binding sites was predicted on 3'UTR of AGPAT6(1-acylaglycerol-3-phosphate O-acyltransferase 6). There were 3 and 2 numbers of different location respectively on 3'UTR of FASN and BTN1A1 targeting by miR-103. The results of ΔG analysis (ΔG ＞ -20 kcal/mol) of flanking regions of 50 miRNAs binding sites showed that 9 miRNA were related to fatty acid metabolism, miR-103/BTN1A1, miR-15/FASN, miR-23/LPL(lipoprotein lipase), miR-27/PPARγ(peroxisome proliferator-activated receptor γ), miR-29/GPR41(orphan g protein-coupled receptor family, member 41), miR-146/BTN1A1, miR-195/FASN, miR-200/SCD(Stearoyl-CoA desaturase) and miR-497/GPR41. And there were highly homology on the binding sites of miR-103/BTN1A1, miR-27/PPARγ, miR-195/FASN among species，which sthrengthened the possibility of the connection between miRNA and their targets. Also, the numbers of one side and two sides of flanking regions of miRNA/mRNA binding sites whose ΔG were smaller than threshold were 14 and 9, respectively. Among all the predicted targets, FASN, ACOX1(acyl-CoA oxidase 1), LPL and PPARγ were targets of miR-27. FASN, BTN1A1 and ACOX1 were both targets of miR-103 and miR-15. 5 pri-miRNA (pri-miR-103-1/23a/27a/146b/200a) were cloned from DNA template from blood of Xinong Saanen dairy goat(Capra hirus). The sequence and secondary structure analysis demonstrated that all the 5 primary miRNA(pri-miRNA) comprising completed pre-miRNA and the stem loop structure could generate functional miRNA in vivo. The results of homology analysis showed that the homology of 4 pre-miRNA of goat were 100 % with cow except for pre-miR-27a whose homology was 98 % (There was a G located in the 11 base from 3' end of pre-miR-27a of goat instead of A of cow). In conclusion, those 9 miRNAs can regulate fatty acid metabolism in goat mammary gland, and cloning of 5 pri-miRNAs provides a basis for their function studying.
