Detection of MCMV IE RNA by RT-PCR. All the eyeballs of the rats were divided into two parts: anterior segment tissue, including the dissected cornea, iris and ciliary body, and posterior segment tissue, including the retina. At each time point, samples from four independent rats in each group were pooled for RT-PCR examination. The results are representative of three separate experiments. Lane M, DNA marker; Lanes 1–3, 1–3 dpi; Lane 4, 7 dpi; Lane 5, 14 dpi; dpi, days postinfection.