THE FATE OF GENETICALLY MARKED HUMAN ORAL KERATINOCYTES IN-VITRO

The fate of the progeny of human oral gingival keratinocytes was mappe d in stratified epithelial tissues in vitro by following the expressio n of a marker gene in genetically related clones. Oral epithelial prog enitor cells were genetically marked at high efficiency by transducing them with a retrovirus vector that carried the gene for a histochemic ally detectable product, Escherichia coli beta-galactosidase (beta-gal ). These cells were then grown in submerged cultures and on collagen r afts at the air-liquid interface to demonstrate the distribution of ge netically marked cells in a differentiating tissue in vitro. The dynam ics of transduced cells showed that clonally related cells were arrang ed in discrete units of labelled cells and these clusters were defined as 'clonal proliferation units'. The size and configuration of these units were related to the proliferative potential and differentiating capacity of the cell that was initially transduced. This model demonst rates the relation between clonally related cells and tissue architect ure for oral keratinocytes in vitro.