Expression of M148R and M149R mRNA in cell culture. RK13 cells were infected with wild type MYXV. At different times p.i., mRNA were extracted, subjected to reverse transcription using oligodT primers, following which, PCR was performed using specific primers for M148R, M149R, or M150R. Lane +, positive control, i.e. PCR on T1 DNA; lane –, negative control, i.e. PCR without template; lanes T₀ through T₁₆, cells infected with wild-type MYXV for 0, 2, 4, 8, 12, or 16 h, respectively; lane n.i., mock-infected cells; lane AraC, cells infected with wild-type MYXV for 16 h and incubated with AraC at the time of infection. T₀ corresponds to RNA extractions performed after 1 h of virus adsorption.