Analysis of KHV TK mRNA in KF-1 cell line infected with KHV. KF-1 cells were infected with KHV. At 0 to 7 days post infection total mRNA was prepared from the infected cells and was used in an RT-PCR reaction using primers TK-Rtforward- TK and RTr long (A). 0 time control mRNA was prepared immediately after infection. lanes: M- size markers, 1–8- mRNA of days 0–7 post infection, 9- direct PCR of KHV DNA, 10- uninfected KF-1 cells 11- RNase treated mRNA of day 5 post infection. To confirm the identity of the RT-PCR products, Southern blot hybridization (B) was performed using the cloned TK gene as probe and mRNA of days 0–7 lanes 1–8 consecutively, control KHV – lane 9, and uninfected KF-1 cells as negative control – lane10. The arrow marks the position of the 621 bp product.