Gene Expression Analysis In PK-15 Cells Infected With Foot-and-mouth Disease Virus

It is very important to study viral pathogenesis and host how to resist infection of FMDV effectively. FMDV is a cytocidal virus that causes major changes in host cell machinery shortly after infecting cells. To define the consequences of FMDV infection on host gene expression, we used fluorescence quantitative PCR method to determine the changes of FMDV multiplication in PK-15 cells. Futhermore, we firstly used porcine IVT microarray of 23973 probe sets that interrogated appromixately 23256 transcripts to examine expression levels of mRNAs isolated at 1, 2 and 4h post infection from cultures of infected PK-15 cells. The concentration, purity and integrality of cellular total RNAs were determined. Our results showed that the expression levels of 656 genes were significantly changed during the course of FMDV infection. Among these genes, 429 genes were up-regulated and 227 genes showed down-regulated levels. Large number of infection-regulated genes is involved in molecular mechanisms characteristic of signal transduction, immunity, cellular metabolism, cell cycle, apoptosis, cytoskeleton and protein synthesis and so on. Our data also showed some genes involved in the early stage signal transduction of cellular innate immunity such as Chaperone Hsp90, which showed distinctive up-regulation. In order to study the effection of key molecular of native immunity signal pathway in host cells infected FMDV, the RIG-N and RIG-C genes with different domain was cloned into pEGFP-N1 expression vector separately, named pEGFP-RIG-N and pEGFP-RIG-C. PEGFP-RIG-N and pEGFP-RIG-C eukaryotic expression vectors were transfected PK-15 cells transiently. RIG-N and RIG-C gene express levels were determined by fluorescent quantitation PCR analysis. It was showed RIG-N genes overexpressed in PK-15 cells and activated downstream signal to induce the expression of IFN as well as supressed reproduction of FMDV. However, RIG-C genes overexpressioned in PK-15 cells could not increased the expression of IFN and reduced multiplication of FMDV. Therefore, the results will lay a foundation to study FMDV pathogenesis and the immediate-early signaling events among host and picornavirus interaction.