It was shown with a 3D MDCK cell culture model that the dynamics of PLLP expression increasing in the course of cyst formation in a 3D culture correlates with CRB3 accumulation in the regions of tight junctions and the formation of immature apical junction complexes (IAJCs), which then form mature adherens and tight junctions (TJs). The gene discussed is PLLP; the disease is cyst.