Ecdysteroid induction of cell surface contacts in a Drosophila cell line.

Drosophila Kc cells are usually spherical in shape and are relatively free of cell-cell contacts. Soon after exposure to 20-hydroxyecdysone they develop extensions, assume a fibroblastic shape, and closely adhere to adjacent cells by means of cell-cell contacts to form large multicellular aggregates. This adhesive nature is enhanced with trypsin treatment without disruption of cell shape. Simultaneous addition of 20-hydroxyecdysone and juvenile hormone results in diminished aggregate formation without preventing the changes in cell shape. These factors point to the possibility that 20-hydroxyecdysone stimulates modifications in the cell surface that may be important during embryological differentiation. Key words Kc cells, aggregations, recognition, juvenile hormone.