中国地方猪品种仔猪大肠杆菌抗性的调控机制和功能基因尚不清楚，已成为抗性育种中的瓶颈问题。课题组已对大肠杆菌抗性和敏感型梅山断奶仔猪circRNA、转录组和miRNA的测序结果进行综合分析，构建了ceRNA调控网络并初步确定circRNA_16225—miR-143-3p—TLR5和circ RNA_04962—miR-195—FUT2在大肠杆菌抗性过程中发挥了重要调控作用。本研究利用Northern blot、FISH、过表达和siRNA敲降等试验对这2个circRNA进行系统功能验证，并利用双荧光素酶报告系统、pull down和RIP技术验证circRNA-miRNA-mRNA的作用关系，最后通过细胞黏附等试验进一步分析circRNA及其靶基因与大肠杆菌抗性的关系，以期阐明circRNA对大肠杆菌抗性的调控机制并获得重要的抗性功能基因，解决地方猪品种抗大肠杆菌病育种的关键科学问题。

The functional genes and mechanism regulation of weaning piglet’ resistance to E. coli in Chinese native breeds remain unclear, which has become a bottleneck problem to solve the anti-E. coli disease breeding of Chinese native breeds. Our research group previously performed the comprehensive analysis of circRNAs, transcriptome, miRNAs sequencing of intestinal tissues between Meishan resistant and sensitive to E. coli piglets. On this basis, we preliminary constructed the ceRNA regulatory relationships among circRNA_16225—miR-143-3p—TLR5 and circRNA_04962—miR-195—FUT2, which further indicates circRNA (circRNA_16225, circRNA_04962) and target genes (FUT2, TLR5) play an important regulating role in the resistance to E. coli of weaning piglets. In this study, we systematically verified the function of two circRNAs by Northern blot, RNA-fluorescence in situhybridization, overexpression and siRNA interference. Then, the interaction among circRNA-miRNA-mRNA was verified by luciferase reporter system, RNA pull down, RNA immune coprecipitation (RIP). Finally, we further analyzed the relationship between two circRNAs and target genes and the resistance to E. coli infection by adhesion test of small intestinal epithelial cell in vitro. This research aims at clarifying the mechanism of two circRNAs regulating the resistance to E. coli, and is expected to obtain function genes related to E. coli infection, which provide guidance for solving key scientific problems about the breeding of disease resistance to E. coli in Chinese native pig breeds.