EXPRESSION OF CHICKEN VINCULIN COMPLEMENTS THE ADHESION-DEFECTIVE PHENOTYPE OF A MUTANT MOUSE-F9 EMBRYONAL CARCINOMA CELL

A mutant cell line, derived from the mouse embryonal carcinoma cell li ne F9, is defective in cell-cell adhesion (compaction) and in cell-sub strate adhesion. We have previously shown that neither uvomorulin (E-c adherin) nor integrins are responsible for the mutant phenotype (Calog ero, A., M. Samuels, T. Darland, S. A. Edwards, R. Kemler, and E. D. A damson. 1991. Dev. Biol. 146:499-508). Several cytoskeleton proteins w ere assayed and only vinculin was found to be absent in mutant (5.51) cells. A chicken vinculin expression vector was transfected into the 5 .51 cells together with a neomycin-resistance vector. Clones that were adherent to the substrate were selected in medium containing G418. Tw o clones, 5.51Vin3 and Vin4, were analyzed by Nomarski differential in terference contrast and laser confocal microscopy as well as by bioche mical and molecular biological techniques. Both clones adhered well to substrates and both exhibited F-actin stress fibers with vinculin loc alized at stress fiber tips in focal contacts. This was in marked cont rast to 5.51 parental cells, which had no stress fibers and no vinculi n. The mutant and complemented F9 cell lines will be useful models for examining the complex interactions between cytoskeletal and cell adhe sion proteins.