Preferential amplification and phenotypic selection in a population of deleted and wild-type mitochondrial DNA in cultured cells.
In order to study the still poorly understood dynamics of mitochondrial gene segregation, we attempted to alter the percentage of deleted mtDNA (del-mtDNA) over wild-type mtDNA in cell-culture by manipulating respiratory chain capacity. For this purpose, we used a cell-line harbouring a 6-kb mtDNA-deletion which normally was present in 70% of the molecules. The results show that in the presence of low concentrations of doxycycline (DC), an inhibitor of mitochondrial protein synthesis, the average percentage of del-mtDNA in culture steadily declined. After short-term DC treatment most cells still contained del-mtDNA and removal of DC led to a rapid increase in the proportion of del-mtDNA. In contrast, long-term DC treatment rendered del-mtDNA undetectable by Southern analysis, reflecting the complete absence of del-mtDNA in most cells. In this case, del-mtDNA in culture remained at a constant low level after removal of the drug. The results clearly show the importance of phenotypic selection in the segregation of a deleterious mtDNA mutation.
Spelbrink
J N
JN
Department of Biochemistry, Academic Medical Center, University of Amsterdam, PO Box 22700, 1100 DE Amsterdam, The Netherlands.
Zwart
R
R
Van Galen
M J
MJ
Van den Bogert
C
C
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002455:Cell Division / Q000235:genetics; D002478:Cells, Cultured; D002950:Citrate (si)-Synthase / Q000378:metabolism; D004272:DNA, Mitochondrial / Q000187:drug effects / Q000235:genetics*; D004318:Doxycycline / Q000494:pharmacology; D003576:Electron Transport Complex IV / Q000378:metabolism; D005784:Gene Amplification; D006801:Humans; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology*; D010182:Pancreatic Diseases / Q000235:genetics* / Q000473:pathology; D010641:Phenotype; D012641:Selection, Genetic; D017384:Sequence Deletion; D013577:Syndrome
D000900:Anti-Bacterial Agents; D004272:DNA, Mitochondrial; D003576:Electron Transport Complex IV; D002950:Citrate (si)-Synthase; D004318:Doxycycline