FIG. 3.
Analysis of EBV latent-gene expression in EBV-infected PGE-5 cell clones. (A) Immunoblotting for detection of EBNAs and LMP1. The blots were probed with pooled human sera for EBNA1, EBNA2, EBNA3A, EBNA3B, and EBNA3C (top blot), MAb PE2 for EBNA2 (middle blot), and MAb CS1-4 for LMP1 (bottom blot). Protein samples extracted from 105 cells were loaded per slot. (B) In situ hybridization for EBER1. An EBV-infected PGE-5 clone was hybridized with the antisense oligoprobe (left) and with the sense oligoprobe (right). Intense nuclear signals are evident only with the antisense probe. (C) RT-PCR analysis of EBV latent-gene expression and EBNA promoter usage in EBV-infected clones. Akata cells were used as a positive control for detection of Qp-initiated EBNA mRNA, and LCL was used as a positive control for detection of LMP1, LMP2A, LMP2B, and BARF0 mRNAs and Cp- or Wp-initiated EBNA mRNAs. Parental PGE-5 cells served as a negative control.