Tissue-specific expression of hepatic functions. Genetic aspects.
Intertypic hybrids formed by fusing dissimilar cell types generally fail to express the tissue-specific products of either parent, a phenomenon termed extinction. To explore the genetic basis and phenotypic complexity of this phenomenon, 15 liver-specific cDNA clones have been used as probes to assay expression of the corresponding mRNAs in a series of hepatoma x fibroblast hybrids retaining different fibroblast chromosomes. Thirteen of the 15 liver-specific mRNAs were extinguished in karyotypically complete hepatoma x fibroblast hybrids, but were reexpressed in hybrid segregants that had eliminated fibroblast chromosomes. In three cases analyzed in detail, extinction of a particular hepatic marker required the presence of a single, specific fibroblast chromosome. These data define and localize a set of discrete genetic loci, the Tse loci, that negatively regulate liver-specific gene expression in trans.
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Fournier
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D000418:Albumins / Q000235:genetics; D000818:Animals; D002460:Cell Line; D004247:DNA / Q000235:genetics; D004274:DNA, Recombinant; D004622:Embryo, Mammalian; D005347:Fibroblasts; D005786:Gene Expression Regulation; D006822:Hybrid Cells; D008099:Liver / Q000378:metabolism*; D008114:Liver Neoplasms, Experimental / Q000235:genetics*; D051379:Mice; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats
D000418:Albumins; D004274:DNA, Recombinant; D012333:RNA, Messenger; D004247:DNA