Submitted to: Virology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/22/2010
Publication Date: 5/23/2010
Citation: Zhu, J.J., Weiss, M., Grubman, M.J., De Los Santos, T.B. 2010. Differential gene expression in bovine cells infected with wild type and leaderless foot-and-mouth disease virus. Virology. 404(1):32-40. Interpretive Summary: Foot-and-mouth disease virus (FMDV) causes an economically devastating disease of cloven-hoofed animals. To develop strategies necessary to control this disease it is important to understand how the virus and host interact. Identification of mechanisms that the host can utilize to rapidly control and contain virus replication may result in disease control approaches that are able to augment current and potential new vaccine strategies. We have developed a weakened version of FMDV, a leaderless virus, that lacks a portion of the viral genome, the protein coding region. This virus is highly attenuated when inoculated into cattle or swine, but can replicate to a limited extent. However, after aerosol infection of cattle the leaderless virus remained localized in the lungs and in contrast to virulent virus did not spread to other areas of the animal and cause disease. In certain cell cultures, we found that leaderless virus infection induced a host antiviral response that blocked virus spread and we have identified host proteins that directly inhibit virus replication. Over the past few years we have initiated a program to understand the mechanism by which leaderless virus is attenuated. We have demonstrated that the FMDV leader protein is involved in degrading a cellular protein, nuclear factor-kappa B which participates in inducing the host cell antiviral response. To gain a more comprehensive understanding of the mechanism of L protein inhibition of the host antiviral response we used a genomics approach and performed microarray analysis of bovine cells infected with wild type or leaderless virus. We identified 39 genes that were selectively up-regulated in leaderless vs wild type virus infection. Most of the up-regulated genes corresponded to interferon-inducible genes, chemokines or transcription factors. Promoter sequence analysis suggested that the transcription factors nuclear factor kappa-B, interferon stimulated gene factor -3 and interferon regulatory factor-1 specifically contributed to the differential gene expression and statistical analysis indicated that the transcription factor nuclear factor kappa-B is the primary effector of the differential expression. Understanding the mechanism of FMDV inhibition of the host antiviral response at the molecular level should be helpful in the development of specific antiviral strategies that can rapidly inhibit or limit virus spread.
Technical Abstract: The leader proteinase (Lpro) of foot-and-mouth disease virus (FMDV) plays a critical role in viral pathogenesis. Molecular studies have demonstrated that Lpro inhibits the translation of host capped mRNAs and transcription of some genes involved in the innate immune response to viral infection. Here we have used microarray technology to study the gene expression profiles in primary embryonic bovine kidney cells infected with wild type (WT) or leaderless virus. Out of 43,803 gene probes, 39 genes were significantly up-regulated in leaderless as compared to WT virus infected cells. Most of the up-regulated genes corresponded to interferon inducible genes, chemokines or transcription factors. Promoter sequence analysis suggested that the transcription factors nuclear factor–kappa-B, interferon stimulated gene factor-3 and interferon regulatory factor-1specifically contributed to the differential gene expression. Statistical analysis indicates that the transcription factor nuclear factor–kappa-B is primarily responsible of the differential expression between wild type and leaderless FMDV infected cells.