Fig. 1. Cell-cell contact loss of RIE1-5, but not RIE1-5/1, cells after OXO treatment. (A) Stable cell lines ectopically expressing integrin 5 (RIE1-5) or tailless 5 (RIE1-5/1) were maintained, as described in Materials and Methods. Images for subconfluent cells in normal culture media were taken using a microscope equipped with a digital camera. Both cell lines generally form colonies. (B) Whole cell lysates from subconfluent cells were prepared for immunoblotting using an antibody against an extracellular region (5exo) or the cytoplasmic tail (5cyto) of the human integrin 5 subunit, or -tubulin. Data shown represent at least three independent experiments. (C) Chemical structure of 6-(1-oxobutyl)-5,8-dimethoxy-1,4-naphthoquinone (OXO). (D,E) Cells were seeded onto 10% FBS-DMEM-H-coated glass coverslips. Once confluent monolayers had been formed by incubation in 5% CO₂ at 37°C, cells were treated with either vehicle (DMSO) or OXO (10 µM) for 24 hours, prior to being immunostained for ZO1 (D) or -catenin (E). Data shown are representative of three different experiments.