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The isolation of an antimycin A-resistant human cell line
Abstract:
An antimycin A-resistant derivative of the human cell line, D98, has been obtained by selective mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. The derivative, designed MA65, is capable of continuous growth in 15 microM antimycin and the resistant phenotype is stable in the absence of selection. MA65 is not cross-resistant to chloramphenicol or triethyl tin. Crude membrane preparations from MA65 after propagation in medium containing antimycin have normal succinate-cytochrome c oxidoreductase activity and the respiratory activity of whole cells continues in the presence of the drug. The mitochondrially synthesized proteins of D98 and MA65 are similar when compared on sodium dodecyl sulphate (SDS), or isoelectric focusing gels, but there is a reproducible difference in the extent of labelling of one band detected by isoelectric focusing. Genetic analysis is consistent with the existence of a cytoplasmically localized determinant conferring resistance.
Insights
Researchers developed a new human cell line, MA65, resistant to antimycin A. This antimycin A resistance is stable and cytoplasmically inherited, offering a valuable tool for mitochondrial research.
Area of Science:
- Cell Biology
- Biochemistry
- Genetics
Background:
- Antimycin A is a potent inhibitor of mitochondrial complex III.
- Understanding resistance mechanisms is crucial for studying mitochondrial function and drug development.
Purpose of the Study:
- To develop and characterize a human cell line resistant to antimycin A.
- To investigate the genetic and biochemical basis of antimycin A resistance.
Main Methods:
- Selective mutagenesis of the D98 human cell line using N-methyl-N'-nitro-N-nitrosoguanidine.
- Phenotypic characterization of the resistant cell line (MA65) for growth, stability, and cross-resistance.
- Biochemical assays of mitochondrial respiratory chain activity (succinate-cytochrome c oxidoreductase).
- Analysis of mitochondrially synthesized proteins using SDS-PAGE and isoelectric focusing.
- Genetic analysis to determine the inheritance pattern of resistance.
Main Results:
- A stable antimycin A-resistant human cell line (MA65) was generated, capable of continuous growth in 15 microM antimycin A.
- MA65 exhibited resistance specifically to antimycin A, with no cross-resistance to chloramphenicol or triethyl tin.
- Membrane preparations and whole cells showed normal respiratory activity in the presence of antimycin A.
- Mitochondrial protein analysis revealed a reproducible difference in the labeling of one protein band between D98 and MA65 cells.
- Genetic analysis indicated a cytoplasmically localized determinant for resistance.
Conclusions:
- MA65 is a valuable tool for studying antimycin A's effects on mitochondrial function.
- The resistance is stable, specific, and likely conferred by a cytoplasmically inherited factor.
- A specific mitochondrial protein may be involved in the observed antimycin A resistance.