Assembly of the Murine Leukemia Virus Is Directed towards Sites of Cell–Cell Contact
Figure 7
MLV assembly is directed towards sites of cell–cell contact.
(A–I) Analysis of nine representative time-lapse videos monitoring MLV assembly in HEK293 cells in contact with XC target cells as described in Figure 6B. The individual panels represent the merged images of all frames of each video. Single-particle tracking was applied to identify all de novo assembly events and to calculate assembly frequency within and outside the cell–cell contact zone. The resulting fold enhancement of MLV assembly at sites of cell–cell contact over the remaining plasma membrane is presented at the top right of each panel. For detailed analysis, see Table S2. For comparison, (A) depicts the analysis from Figure 6B. The corresponding videos for (A, B, and C) are Videos S3, S4, and S5, respectively. (J) An analysis as in (A) was performed for cocultures between a MLV-producing HEK293 cell that expresses dynamin2-CFP to label the cell–cell contact and a XC target cell expressing actin-binding Lifeact-CFP. The corresponding video for panel (J) is Video S6. (K) An analysis as in (A) was performed for cocultures between a MLV-producing HEK293 cells and a HEK293 cell expressing mCAT1-CFP. The corresponding video for panel (K) is Video S7. (L–N) An analysis as in (A) was performed for cocultures between MLV-producing Cos-1 cells and XC target cells. The corresponding video for (N) is Video S8. Size bars correspond to 15 µm.