Figure 2.

Changes in Rev activity during progression of clinical disease [8]. In vitro biological activity of Rev variants from pony 524 was quantified in transient transfection assays using 293T cells as previously described [3]. Briefly, Rev variant cDNAs were co-transfected with a chloramphenicol acetyltransferase (CAT) reporter plasmid (pERREAll) in HEK293T cells and CAT activity was quantified as percent acetylation. The results are presented as a percentage of activity compared to R1, the founder variant in the inoculum. The overall Rev activity for each time point was calculated as the average Rev activity of tested variants, weighted by the frequency of the tested variant in the sampled population. Solid bars indicate the rectal temperature of pony 524. The clinical stages of disease are indicated as: Acute, Chronic, Inapparent, and Rec (recrudescent).