Several opossum kidney epithelial cells join together to briefly form a circle early during the playback of this live cell time-lapse sequence. Shortly after, however, other cells migrate into the area and the geometrical configuration is lost. The highly active OK cells appear to be trying to fill in all available space in the imaging chamber to form a contiguous sheet of cells, similar to the epithelial sheets found in the vertebrate body. Epithelial sheets characteristically consist of tightly packed cells adjoined to one another via specialized junctions that are crucial for their primary function, which is to act as barriers to diffusion.

Many of the OK cells in the chamber can be observed undergoing cell division. Immediately prior to the process, the cells retract their flattened lamellipodia and narrow filopodia and assume a roughly spherical geometry. Cytokinesis generally occurs at the equator of the parent cell, where a temporary contractile ring composed of actin, myosin, and associated proteins is formed. When the cleavage furrow develops in this location, that daughter cells that result should be of similar size and consistency.

Blebbing of the surfaces of newly formed daughter cells is common. The dynamic hemispherical blebs gradually disappear, however, as the cells settle on the substratum and extend flattened lamellipodia around their peripheries. Notably, cultured OK epithelial cells have difficulty completing the division process if there is no available space along the substratum for the daughter cells to make contact with. One set of featured OK daughter cells formed late in the video experiences particular trouble, seeming to be pushed along by the surface movements of other cells all the way from the upper to the lower field of view before an opening is finally found and the cells are able to lose their spherical form as they stretch across the surface of the imaging chamber.