(A, B) The expression of BZLF1 , BRLF1 , BHRF1 (lytic) and BLLF1 examined by RT-PCR, and methylation of Zp and Rp analyzed by MSP in EBV-positive cell lines. M, methylated; U, unmethylated. (C, D) BGS analyses of Zp and Rp methylation status in Burkitt lymphoma (BL) and lymphoid (LCL) cell lines. Circles, CpG sites analyzed; row of circles, an individual promoter allele sequenced; Filled circle, methylated; empty circle, unmethylated. "x" circle, CpG site abolished by sequence variation or undetermined methylation status due to unconverted C in nearby CpN site.