Figure 2
mt-nucleoids undergo frequent attachment and detachment during the cell cycle. (a) Time-lapse series of confocal images of mt-nucleoids (green) and mitochondria (red). mtDNAs were stained with SYBR Green I in HeLa cells expressing mitochondrially targeted DsRed (HeLa-Su9 cells). Lower panels show the fluorescence intensity of SYBR Green I as heat map images. Arrowheads show each mt-nucleoid. Scale bar, 1 μm. (b) Proportion of mt-nucleoids undergoing attachment or detachment per cell during the cell cycle mtDNAs were stained with SYBR Green I in Fucci2 cells. A total of 20 mt-nucleoids per cell were randomly selected and analyzed. Error bars indicate standard deviation (ncells = 5 for each phase). The statistical significance of differences in attachment and detachment was examined by analysis of variance (p = 0.1005). N.S., not significant. (c) The frequency of attachment and detachment per mt-nucleoid for 2 min during the cell cycle. mtDNAs were stained with SYBR Green I in Fucci2 cells. mt-nucleoids undergoing attachment and detachment were analyzed for the number of attachments and detachments. A total of 20 mt-nucleoids per cell were randomly selected and analyzed. Error bars indicate standard deviation (ncells = 5 for each phase). The statistical significance of differences in attachment and detachment was examined by paired t-test (G1, p = 0.1739; early-middle S, p = 0.9780; late S-G2, p = 0.2253). N.S., not significant.
