FIG 6.

rEBV lacking the BHLF1 ORF alone is unable to sustain Lat III. EBV latency gene expression was assessed in BL2 cells infected with ΔBHLF1 rEBV at 18 to 386 days p.i., as described in the legend for Fig. 4. (A) Detection of EBNA and LMP1 expression by immunoblotting. (B) Detection by endpoint RT-PCR of EBNA1 mRNAs from Cp/Wp or Qp and of EBNA3C mRNA at 18/23, 60, and 92 dpi. The smaller EBNA3C cDNA bands detected at 60 and 92 days p.i. in ΔBHLF1 rEBV-infected cell line 2 were determined by DNA sequence analysis to be splicing variants of the EBNA3C mRNA. BL2 cells infected in parallel with WT rEBV failed to transition to Lat I (data not shown), as also observed independently in Fig. 4.