FIG 3.
SRPK1 regulation of EBOV transcription/replication. (A) Dose-dependent effect of SRPK1 in the EBOV minigenome assay. HEK293 cells were transfected with plasmids encoding EBOV minigenome assay components (NP, VP35, L, the EBOV-specific minigenome, T7 polymerase, the absence or presence of each VP30 phenotype, and a plasmid encoding firefly luciferase for normalization). Different amounts of the SRPK1-encoding plasmid (0, 100, or 500 ng) were cotransfected. The results obtained with phosphorylation-independent VP306A were set to 100%. Samples prepared in the absence of VP30 (ΔVP30) represent the baseline levels of the assay. Statistical analysis by a t test was applied between 0 ng of SRPK1-coding plasmid-transfected cells and either of the other treatments. (B) Effects of specific inhibition of SRPK1 by the inhibitor SRPIN340 on EBOV transcription/replication. HEK293 cells were transfected with plasmids encoding EBOV minigenome assay components (see above). At 30 h p.t., cells were incubated with either DMSO (control), 25 nM OA, or a mixture of 25 nM OA and 30 μM SRPIN340. At 48 h p.t., cells were lysed, and reporter gene activity was analyzed as indicated above for panel A. The means and SD from three independent experiments are indicated. Statistical analysis by a t test was applied between 25 nM OA and a mixture of 25 nM OA and 30 μM SRPIN340. Asterisks indicate statistical significance (*, P < 0.05; ****, P < 0.0001).