Fig. 3

a–t Detection of EGFP, MCMV-E1 and MCMV-M45 in rMCMV1373- or 448-infected MEF and primary neuronal cultures. Either rMCMV was allowed to infect both cell cultures at a MOI of 1. Virus-infected MEF and primary neuronal cultures were sampled at 2 and 4 dpi, respectively. a–d rMCMV1373-infected MEFs. e–h rMCMV448-infected MEFs. i–n rMCMV1373-infected primary neuronal culture. o–t rMCMV448-infected primary neuronal culture. In each rMCMV-infected culture, phase contrast (a, e, i, o) and fluorescence views of EGFP (b, f, j, n, p, t), immunofluorescence for MCMV-E1 (red) (c, g, k, q) and MCMV-45 (red) (m, s) and merged images of EGFP and MCMV-E1 (d, h, l, r) are shown. Arrow heads in p–t indicate EGFP⁺ cells. Scale bar: 50 µm. u, v Comparison of the numbers of EGFP⁺- or MCMV-E1⁺ cells in MEF (u) and primary neuronal cultures (v) infected with rMCMV1373 or rMCMV448. MEF and primary neuronal cultures were infected with rMCMVs at three different MOIs and analyzed at 2 and 4 dpi, respectively. Additionally, in primary neuronal cultures (v) the numbers of cells doubly positive for EGFP and NeuN as shown in Fig. 4 were counted. The cell counts of 3 different fields (292 × 220 µm; 0.064 mm²/a field) were averaged in each coverslip. Mean ± SEM of 3 different coverslips in each experimental group are shown (E1⁺, white bar; EGFP⁺, gray bar; EGFP^+/NeuN⁺, black bar). Averaged numbers of total cells as DAPI⁺ nuclei were 339 ± 31/0.01 mm² and 305 ± 20/0.01 mm², in virus-infected MEF and primary neuronal cultures, respectively. The averaged percentage of NeuN⁺ cells in primary neuronal cultures infected with rMCMVs was 87.6 ± 3.6%. *p < 0.01 vs. corresponding rMCMV1373-infected culture in each experimental group by an unpaired 2-tailed Student’s t-test