FIG. 1.

Inhibition of EBOV replication in Rat2-NZAP-Zeo cells. (A) Immunofluorescence analysis of NZAP-Zeo-expressing cells infected with Zaire-EBOV. Rat2-Zeo cells expressing the empty vector or Rat2-NZAP-Zeo cells expressing the N-terminal portion of ZAP fused to the product of the zeocin resistance gene were infected with Zaire-EBOV at an MOI of 1. Five days p.i., cells were fixed and immunofluorescence analysis was performed using a monoclonal antibody directed against Zaire-EBOV NP protein. (B) Growth kinetics of Zaire-EBOV. Rat2-Zeo cells or Rat2-NZAP-Zeo cells were infected with Zaire-EBOV at an MOI of 0.01 or 5. The amount of Zaire-EBOV-specific RNA in the supernatant was quantified using a Zaire-EBOV-specific real-time RT-PCR. The data represent the means and ranges of duplicate infection experiments. Dashed line, detection limit. (C) Determination of infectious virus titer. Rat2-Zeo or Rat2-NZAP-Zeo cells were infected with Zaire-EBOV or Sudan-EBOV at an MOI of 0.01 or 5. Seven days p.i., the amount of infectious virus released into the supernatant was determined by immunofocus assay on Vero-E6 cells. (D) Northern blot analysis of Zaire-EBOV NP-specific RNA. Rat2-Zeo or Rat2-NZAP-Zeo cells were infected with Zaire-EBOV at an MOI of 1. Five days p.i., total RNA was isolated and Northern blot hybridization was performed with a ³²P-labeled probe directed against Zaire-EBOV NP RNA. Noninfected cells served as a control. The methylene blue-stained 28S RNA is shown below the blot as a semiquantitative marker for gel loading and RNA transfer.