Figure 1

F and HN co-expression does not cause mitochondrial damage rather than maintaining its integrity. A Representative images of the colocalization between DsRed-Mito and endogenous TIM23 response to F and HN co-transfection. A549 cells were transfected with both viral plasmids (Flag-F and HA-HN) and DsRed-Mito. At 0, 6, 12, 18 and 24 hpt, the coverslips were examined via indirect immunofluorescence assay (IFA) in accordance with previously described protocol [4]. Syncytia formation can be observed on the basis of nuclei and indicated by a white dot circle. Blue (Nuclei), Green (endogenous TIM23), Red (mitochondria) and Yellow (Red + Green) denote overlapping of markers. The Person’s Rr, and the Overlap_R of zoomed out section were revealed, and both of them were calculated using Image J (National Institutes of Health, Bethesda, MD, USA). Pearson’s_Rr ranged from − 1.0 to 1.0, where 0 indicated no significant correlation and − 1.0 implied a complete negative correlation. Overlap_P ranged from 0 to 1.0, where 0.5 denoted that 50% of both selected channels were colocalized. B Representative images of colocalization between GFP-Mito and endogenous Tim23 response to F and HN co-transfection. A549 cells were transfected with both viral (Flag-F and HA-HN) and EGFP-Mito plasmids. Syncytium formation could be observed on the basis of nuclei and indicated by a white dot circle. All of the coverslip samples were collected at the corresponding marked time points, and this procedure was repeated at least twice. At 0, 6, 12, 18 and 24 hpt, the coverslips were examined via IFA in accordance with previously described protocol [4]. Blue (Nuclei), Green (mitochondria), Red (endogenous TIM23) and Yellow (Red + Green) denote overlapping of markers. The Person’s Rr, and the Overlap_R of zoomed out section were revealed, and both of them were calculated using Image J (National Institutes of Health, Bethesda, MD, USA).