Abstract: 【Objective】The previous study made by the authors’ group had screened out two microRNAs with extremely significantly increased expression for E.coli F18 infection: miR-192 and miR-215, using Illumina Solexa high-throughput sequencing technology combined with fluorescence quantitative determination. The objective of this study is to understand the miR-192/ miR-215 expression and further screen out the key target genes of miR-192 and miR-215 regulating E.coli F18 infection, which will lay a foundation for probing into the molecular mechanisms of regulating E.coli F18 infection in weaned piglets. 【Method】Real-time PCR was used to detect the miR-192/miR-215 expression in different tissues of Meishan piglets at 35 days of age, meanwhile conservative sequence was analyzed using MEGA 5.0 software. The algorithms TargetScan was used to predict miR-192/miR-215 putative target genes, whose enrichment of Gene Ontology and Pathway was analyzed, respectively. Then the functional classification of target protein was further conducted using DAVID, finally, the intersection between predicted target genes and regulatory genes was taken for the resistance to E. coli F18 infection of weaned piglets which were screened out by the previous study. 【Result】 The results indicated that miR-192/miR-215 were highly expressed in the duodenum and jejunum tissues of Meishan piglets at 35 days of age. The mature sequences of miR-192 and miR-215 are highly conservative in vertebrates. A total of 156 target genes of miR-192/miR-215 were exactly the same, which were significant enrichment in Axon guidance pathway and in 25 GO function (P＜0.05). Target proteins were divided into 12 categories according to the function, and most of the target proteins belonged to phosphoprotein with signal transduction function and DNA binding protein. Through intersection between target genes and regulatory genes (Gene Expression Omnibus, Accession number: GSE26854) for the resistance to E. coli F18 infection, five important target genes such as ALCAM【Conclusion】The results of this study revealed that miR-192 and miR-215 were two important factors of participating in maintaining the intestines function and resisting the E.coli F18 infection, DLG5 was likely to be the important target gene of miR-192 and miR-215 regulating E.coli F18 infection, and further analyses should be conducted to testify whether the DLG5 could be an effective genetic marker for the resistance to E.coli F18 infection in Chinese native pig breeds., DLG5, FRMD4B, MIPOL1 and ZFHX3 were attained. From the point of target genes function, DLG5 was an important factor for maintaining epithelial cells structural integrity.

Key words: pig, miR-192, miR-215, expression profile, target gene, E.coli F18