FIG. 1.
In situ hybridization for SV40 DNA in the DBA24 spontaneous LCL. A small fraction of cells (1 to 2 of every 500) was positive for SV40 DNA. At higher magnification (inset), the SV40 signal can be seen as dense grains over the nucleus. Bar = 20 μM (main panel) and 12.5 μM (inset).