A small epithelial cell is tethered to an unusually large trinucleated cell by a thin strand of membrane-enclosed cytoplasm. Similar to many other animal cells in culture, the large LLC-MK2 cell assumes a roughly spherical shape prior to division. Even during the cell’s drastic transfigurement, however, the strand of material connecting it to its partner cell is not broken. Following cytokinesis, it becomes clear that three daughter cells, each containing only a single nucleus, are produced by the division of the trinucleated cell.

The new daughter cells undergo various contortions for a brief time before they begin to settle on the surface of the imaging chamber. The broad, flattened lamellipodia they extend around their peripheries gives the cells an appearance similar to irregularly shaped fried eggs. Assuming their own polarity, the daughter cells begin to migrate in different directions, but are not able to stay apart for long. The tendency of epithelial cells to group into small colonies in culture is demonstrated by their activity.

The initial steps of cell death can be observed in the small aforementioned epithelial cell near the end of the time-lapse sequence. The surface extensions of the LLC-MK2 cell are retracted and it appears to experience cytoplasmic shrinking. Also, the central region of the cell, where the nucleus and mitochondria had formerly been clearly identifiable, takes on a disorganized appearance. Though the cell is still intact at the end of the video, many cells that die in culture eventually experience cytoplasmic fragmentation, resulting in the cell debris that often flows into the field of view during time-lapse studies.