Submitted to: American Society for Virology Meeting
Publication Type: Abstract Only
Publication Acceptance Date: July 12, 2003
Publication Date: July 12, 2003
Citation: Neill, J.D., Ridpath, J.F. Serial analysis of gene expression in bovine viral diarrhea virus 2 infected cells provides evidence for inhibitionof cap-dependent translation initiation. American Society for Virology Meeting. 2003. p. 239. Abstract No. P25-7. Technical Abstract: Bovine viral diarrhea virus type 2 (BVDV2) strain 1373 , a highly virulent noncytopathic strain, causes high fever, thrombocytopenia, lymphoid depletion and immune suppression. The mechanisms by which these lesions are produced are unknown. Serial analysis of gene expression (SAGE) was used to develop a global overview of gene expression changes in BVDV2-infected cells. SAGE is a sequence-based technology that can quantitate virtually every transcript in a cell type without prior sequence information. Transcript expression levels were determined by sequencing libraries composed of 14 base DNA fragments (tags) derived from the 3' end of each mRNA transcript. Comparison of the gene expression levels between noninfected and BVDV2 1373-infected cells showed that transcription of genes encoding several translation initiation factors was decreased. These genes included eIF-1, eIF-2beta, eIF-4b, and eIF-4e cap binding protein and were down-regulated by >4-, 5-, 2.3-, and 4-fold, respectively. Interestingly, the gene encoding the negative regulator of eIF-4e, eIF-4e binding protein showed a 7-fold increase in transcription. Decreases in eIF-1 and the eIF-4 cap binding complex could indicate inhibition of cap-dependent translation initiation. Western blot analysis of infected cell lysates prepared at 48, 96 and 144 hours post-infection was done using anti-eIF-4e and eIF2alpha (native and phosphorylated proteins) antibodies. The native eIF-4e was detected at each time point, but concentration decreased with time. The phosphorylation that results in the activation of eIF-4e was not visible 96 and 144 hours post-infection. eIF-2alpha was present at near equivalent levels at all time points and showed little phosphorylation above control levels. Taken together, these data indicate that there may be inhibition of cap-dependent translation initiation caused by decrease in critical proteins. Lack of phosphorylation of eIF-2alpha indicates that there is no inhibition through mechanisms such as the double-stranded RNA-dependent protein kinase PKR.