title: Establishment and characterization of ethidium bromide resistance in simian virus 40-transformed hamster cells. Effects on mitochondria in vivo.
abstract: This study describes the isolation and subsequent characterization of four mammalian cell lines resistant to ethidium bromide (EB). Treatment of the simian virus 40- (SV40) transformed hamster cell line F5-1 first led to the establishment of the F2 cell line, which is resistant to 2 microg EB/ml. At this concentration cytochromes c and b are present in almost normal or only slightly diminished amounts, whereas cytochromes a + a(3) show an obvious decrease. The mitochondria of the F2 cell show a normal ultrastructure, not distinct from the parental cell line F5-1, and contain closed circular DNA. The sensitive parental F5-1 cells, however, when exposed to the same dye concentration exhibit the typical EB-induced ultrastructural changes in the mitochondria, and no more component I mitochondrial DNA can be demonstrated. 1 yr after establishment we derived from the F2 cell three more cell lines, resistant against 4, 8, and 16 microg of EB/ml. These cell lines, termed F4, F8, and F16, respectively, also revealed relatively intact-appearing mitochondria, although distinguishable from F5-1 and F2 mitochondria by a more condensed or unorthodox cristae conformation. F4, F8, and F16 cell lines contained closed circular mitochondrial DNA in the same position as that of the parental F5-1 cells, when analyzed in an isopycnic CsCl-EB gradient. A small shoulder at the lower density side of the DNA I peaks was observed. The newly acquired drug resistance of the F cells is hereditarily transmitted to the progeny cells and retained even after a period of growth in EB-free medium.
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000187:drug effects*; D002499:Centrifugation, Density Gradient; D002999:Clone Cells; D006224:Cricetinae; D003580:Cytochromes / Q000032:analysis; D004270:DNA, Circular / Q000032:analysis; D004272:DNA, Mitochondrial / Q000032:analysis; D004351:Drug Resistance; D004622:Embryo, Mammalian; D004996:Ethidium / Q000494:pharmacology; D005260:Female; D000882:Haplorhini; D006367:HeLa Cells; D007668:Kidney; D008854:Microscopy, Electron; D008928:Mitochondria / Q000032:analysis; D010617:Phenanthridines / Q000494:pharmacology*; D013539:Simian virus 40; D013053:Spectrophotometry
chemical_list: D000998:Antiviral Agents; D003580:Cytochromes; D004270:DNA, Circular; D004272:DNA, Mitochondrial; D010617:Phenanthridines; D004996:Ethidium