T84 human intestinal epithelial cells primarily grow as a monolayer with intact tight junctions (a & b) which are preserved during cell division (c).  T84 cells stably expressing an occludin anti-sense construct under the constitutively active CMV promoter show disrupted junctions and epithelial morphology (d-f).  Note that anti-sense cells lacks contact-inhibition of growth and continues to divide at all layers of the multilayer dysplasic epithelium.  Arrows point to cells in mitosis.  Arrowheads point to lack of tight junction in anti-sense cells (g & h).