Fig. 8.

Cp within the endogenous EBV genome remains silent in superinfected Sal BL cells. The source of Cp-derived transcripts was determined based on a single-nucleotide polymorphism (P) resulting in an MscI restriction site (underlined) in the C1 exon of the superinfecting (Akata) strain of EBV (10). A 174-bp cDNA spanning the C1 and C2 exons (top) was amplified from RNA isolated from Sal cells ∼1 month postsuperinfection, end labeled with ³²P, digested with MscI, and then subjected to polyacrylamide gel electrophoresis and autoradiography; cDNAs generated from Kem III BL and Ak-LCL cells served as controls for detection of the absence and presence of the MscI site, respectively. The lack of detectable cDNA resistant to MscI digestion in the superinfection (SI) lanes indicates that Cp-derived transcripts originated from the superinfecting virus.