Popis: |
Experiments designed to test the hypothesis that imaginal disc evagination may be accomplished by a continuous circumferential constriction of the basally located microfilaments in disc cells [Fristrom, D., and Fristrom, J. W. (1975). Develop. Biol. 43, 1–23] are presented. Discs were cut in various planes so as to interrupt the hypothesized lines of constriction and the resulting fragments tested for the ability to evaginate in vitro. Fragments from each type of cut were able to undergo evagination without resealing of the would surfaces. Furthermore, sections of evaginated cut fragments showed no evidence for a general contraction of the basal cell surface. We conclude that the ability to evaginate is an intrinsic property of each fragment independent of its attachment to the rest of the disc. |