Virus and cell RNAs expressed during Epstein-Barr virus replication

Changes in Epstein-Barr virus (EBV) and cell RNA levels were assayed following immunoglobulin G (IgG) cross-linking-induced replication in latency I-infected Akata Burkitt B lymphoblasts. EBV replication as assayed by membrane gp350 expression was similar to 5% before IgG cross-linking and increased to more than 50% 48 h after induction. Seventy-two hours after IgG cross-linking, gp350-positive cells excluded propidium iodide as well as gp350-negative cells. EBV RNA levels changed temporally in parallel with previously defined sensitivity to inhibitors of protein or viral DNA synthesis. BZLF1 immediate-early RNA levels doubled by 2 h and reached a peak at 4 h, whereas BMLF1 doubled by 4 h with a peak at 8 h, and BRLF1 doubled by 8 h with peak at 12 h. Early RNAs peaked at 8 to 12 h, and late RNAs peaked at 24 h. Hybridization to intergenic sequences resulted in evidence for new EBV RNAs. Surprisingly, latency III (LTIII) RNAs for LMPI, LMP2, EBNALP, EBNA2, EBNA3A, EBNA3C, and BARTs were detected at 8 to 12 h and reached maxima at 24 to 48 h. EBNA2 and LMP1 were at full LTIII levels by 48 h and localized to gp350-positive cells. Thus, LTIII expression is a characteristic of late EBV replication in both B lymphoblasts and epitheliall cells in immune-comprised people (J. Webster-Cyriaque, J. Middeldorp, and N. Raab-Traub, J. Virol. 74:7610-7618, 2000). EBV replication significantly altered levels of 401 Akata cell RNAs, of which 122 RNAs changed twofold or more relative to uninfected Akata cells. Mitogen-activated protein kinase levels were significantly affected. Late expression of LTIII was associated with induction of NF-kappa B responsive genes including I kappa B alpha and A20. The exclusion of propidium, expression of EBV LTIII RNAs and proteins, and up-regulation of specific cell RNAs are indicative of vital cell function late in EBV replication.