GAPDH and infection: As we previously reported with non-PNA-treated E. chaffeensis (Lin et al., 2016), based on the levels of E. chaffeensis 16S rRNA/human GAPDH mRNA, Etf-1-GFP-transfection of HEK293 cells enhanced infection of CTL PNA-treated E. chaffeensis compared to the GFP-transfection CTL (Figure 3A).