Activation of the galectin-1 (L-14-I) gene from nonexpressing differentiated cells by fusion with undifferentiated and tumorigenic cells.
Expression of the galectin-1 (L-14-I) gene, elevated in most differentiated and transformed cell lines, has been studied in cell hybrid systems. Fusion of L-14-I nonproducing rat liver differentiated FAO cells with dedifferentiated rat liver BRL3A cells leads to extinction of liver-specific gene expression while L-14-I mRNA levels remain high. Interspecific hybrids produced by fusion of tumorigenic human osteosarcoma 143TK- with FAO cells show loss of both differentiated functions and tumorigenic phenotype and activation of the FAO L-14-I alleles. Increased expression of rat L-14-I alleles was also observed in human osteosarcoma x rat thyroid cells transient heterokaryons. The data presented here show that expression of the L-14-I gene is subject to dominant positive control and that it correlates with loss of differentiation-specific functions, but it is independent from tumorigenicity. L-14-I activation in FAO cells is achieved by treatment with 5-azacytidine. This result suggests that DNA demethylation is responsible or a prerequisite for L-14-I activation in hybrids.
Chiariotti
L
L
Dipartimento di Biologia e Patologia Cellulare e Molecolare L. Califano, Università degli Studi di Napoli, Italy.
Benvenuto
G
G
Zarrilli
R
R
Rossi
E
E
Salvatore
P
P
Colantuoni
V
V
Bruni
C B
CB
D000483:Alleles; D000818:Animals; D001374:Azacitidine / Q000494:pharmacology; D001483:Base Sequence; D002454:Cell Differentiation / Q000235:genetics*; D002459:Cell Fusion; D002478:Cells, Cultured; D037483:Galectin 1; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D005799:Genes, Dominant; D006388:Hemagglutinins / Q000096:biosynthesis / Q000235:genetics*; D006801:Humans; D008099:Liver / Q000166:cytology; D008114:Liver Neoplasms, Experimental / Q000473:pathology; D008745:Methylation / Q000187:drug effects; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics*; D014411:Neoplastic Stem Cells / Q000378:metabolism*; D012516:Osteosarcoma / Q000473:pathology; D051381:Rats; D014407:Tumor Cells, Cultured
D037483:Galectin 1; D006388:Hemagglutinins; D009363:Neoplasm Proteins; D001374:Azacitidine