Infection of cultured bovine cells with bovine herpesvirus 1 (BHV-1) or Sendai virus induces different beta interferon subtypes

Abstract

In contrast to mice or humans, cattle contain three beta interferon (IFN-β) genes with distinct transcriptional promoters suggesting IFN-β gene expression is not stimulated the same by different viruses. To test this hypothesis, we compared expression of the three IFN-β subtypes after infection with a RNA virus, Sendai, versus a large DNA virus, bovine herpesvirus 1 (BHV-1). Infection of low passage bovine kidney (BK) or established bovine kidney cells (CRIB) with Sendai virus has consistently led to high levels of IFN-β1 RNA. Conversely, infection of CRIB cells, but not BK cells, with BHV-1 increased IFN-β3 RNA levels and to a lesser extent the other two IFN-β subtypes. Inhibition of de novo protein synthesis with cycloheximide resulted in higher levels of IFN-β1 and IFN-β2 RNA levels after BHV-1 infection. Further studies demonstrated that BHV-1 immediate early and/or early genes were primarily responsible for inhibiting the IFN response in BK cells. The three bovine IFN-β promoters were cloned upstream of a reporter gene construct, and their properties analyzed in transient transfection assays. Only the IFN-β3 promoter was trans-activated by IRF3 (interferon responsive factor 3). IRF7 and double stranded RNA (polyIC) stimulated IFN-β1 and IFN-β3 promoter activity, but not IFN-β2. Relative to the human IFN-β promoter, the IFN-β3 promoter contained fewer nucleotide differences in the positive regulatory domain III (PRD III), PRD IV, and PRD I compared to the IFN-β1 and IFN-β2 promoter. Collectively, these studies provide evidence that virus infection differentially stimulates expression of the three bovine IFN-β genes.

Two MicroRNAs Encoded within the Bovine Herpesvirus 1 Latency-Related Gene Promote Cell Survival by Interacting with RIG-I and Stimulating NF-κB-Dependent Transcription and Beta Interferon Signaling Pathways

“…IFN-␤2 RNA levels were increased 3.5-fold at 8 h after infection, whereas a modest 2-fold increase was detected at 4 h after infection with wt BHV-1. Treatment with CHX led to higher levels of IFN-␤1 and IFN-␤2 mRNA by 4 h after infection with the LR mutant virus or wt BHV-1, which was consistent with a previous study (16). These studies demonstrated that IFN-␤1 RNA levels were readily detected in low-passage-number bovine cells following infection with the LR mutant virus but not with wt BHV-1.…”

“…In contrast to humans or mice, cattle contain three IFN-␤ genes (IFN-␤1, IFN-␤2, and IFN-␤3) that are regulated by distinct promoters (16,80,82). BHV-1 infection increases IFN-␤1 and IFN-␤3 RNA levels in established bovine cell lines (16,59) but not in low-passage-number bovine cells (16). When de novo protein synthesis is inhibited by cycloheximide (CHX) treatment, infection of low-passagenumber bovine cells with BHV-1 leads to increased IFN-␤1, but not IFN-␤3, RNA levels (16).…”

“…BHV-1 infection increases IFN-␤1 and IFN-␤3 RNA levels in established bovine cell lines (16,59) but not in low-passage-number bovine cells (16). When de novo protein synthesis is inhibited by cycloheximide (CHX) treatment, infection of low-passagenumber bovine cells with BHV-1 leads to increased IFN-␤1, but not IFN-␤3, RNA levels (16). Relative to wt BHV-1, the LR mutant virus induced higher levels of IFN-␤3 and other IFNstimulated genes in established bovine cells (59), suggesting that expression of an LR-encoded protein interfered with IFN-␤ signaling.…”

“…The bovine IFN-␤ promoters were described previously (16). The human IRF3 and IRF7 expression constructs were obtained from Luwen Zhang (University of Nebraska, Lincoln, NE).…”

“…Chloramphenicol acetyltransferase (CAT) IFN-␤ reporter assays were performed using BTest or 293 cells cultured in 60-mmdiameter dishes as described previously (16). The CAT assays were repeated at least three times to confirm the results.…”