Publishing A MicroRNA Catalog Of Swine Endothelial Cells And Screenning Out MicroRNAs Involved In CSFV Infection

MicroRNA(miRNA)are one class of noncoding small RNAs, which play impotant roles in the process of virus infection. In this study Illumina Solexa sequencing technology was applied to found the potential miRNA in swine umbilical vein endothelial cells (SUVEC)and screened out miRNA involved in Classical swine fever virus (CSFV) infection.(1)We gained 18721836 small RNAs which were less than 35nt, and 13612934 high-quality small RNAs were got by eliminating the low-quality small RNA and liner. SOAP (Short oligonucleotide alignment program)software was used to locate the sRNA in genome, 8547658 perfectly mapped to the pig genome (62.79% of total ). Then rRNA, scRNA, tRNA, snRNA, snoRNA and degradation fragments of mRNA were excluded by comparing to the NCBI GenBank, Rfam, repeat sequences, introns and exons. 5932143 miRNAs were identified which took up 43.58% of total sRNAs.The sequencing results was analyzed by bioinformatics. 154 genes were confirmed to code 116 mature miRNAs and 66 miRNA*, and 4 novel pig-specific miRNAs were found in SUVEC.(2)MiRNA Microarray was poformed to confirm the expresssion of the miRNAs, and screened out the diferential expression miRNAs in classical swine fever virus (CSFV) infected cells. The result showed that 8 miRNAs were up-redulated and 4 miRNAs were down-regulated.(3)The let-7 family that can bind to the CSFV 3'untranslation region(UTR) was predicted by software RNA22. Dual luciferase report vetor was constructed to verify the predicted results. Let-7a, let-7c and let-7i were identified couled bind to the CSFV 3'UTR. Further research on the regulation of let-7 effect on CSFV. The mimics or inhibitor of let-7a, let-7c and let-7i were transfected into SUVECs, then were infected by CSFV. The rsults showed that the mimcs of let-7a and let-7c inhibited the replication of CSFV. CSFV infection upregulated the expression of Nuclear ribonucleoproteins A1 (hnRNAP A1) which led to downregulation of let-7a in SUVEC.This study revealed the function of miRNA in the process of CSFV infection, which provided valuable scientific data for molecular pathogenesis mechanism of CSFV.