Cytokeratin gene expression in hepatoma hybrid cells: evidence for regulation in cis.
The genes encoding intermediate filament (IF) proteins are expressed in a cell-lineage restricted fashion. To analyze the regulation of such genes, we studied cytokeratin and vimentin expression in hepatoma x fibroblast hybrids. These hybrids continued to express both hepatoma cell-derived cytokeratins and fibroblast-specific vimentin. Furthermore, the cytokeratin subunits that were produced were exclusively of rat hepatoma origin. Thus, IF protein genes were neither extinguished nor activated in cell hybrids, providing evidence for regulation in cis. This behavior contrasts sharply with that of most tissue-specific genes, which tend to be regulated in trans in hybrid cells.
Gourdeau
H
H
Department of Molecular Medicine, Fred Hutchinson Cancer Research Center, Seattle, Washington 98104.
Fournier
R E
RE
D000818:Animals; D005786:Gene Expression Regulation; D006822:Hybrid Cells; D015151:Immunoblotting; D007382:Intermediate Filaments / Q000378:metabolism; D007633:Keratins / Q000235:genetics*; D008114:Liver Neoplasms, Experimental / Q000378:metabolism; D011233:Precipitin Tests; D014746:Vimentin / Q000235:genetics
D014746:Vimentin; D007633:Keratins