Open AccessOn the relevance of mitochondrial fusions for the accumulation of mitochondrial deletion mutants: A modelling study
Author(s) -
Kowald Axel,
Jendrach Marina,
Pohl Sandra,
BereiterHahn Jürgen,
Hammerstein Peter
Publication year - 2005
Publication title -
aging cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.103
H-Index - 140
eISSN - 1474-9726
pISSN - 1474-9718
DOI - 10.1111/j.1474-9726.2005.00169.x
Subject(s) - biology , mitochondrial dna , mitochondrion , mitochondrial fission , mutant , mitochondrial fusion , oxidative phosphorylation , genetics , mutation , organelle , microbiology and biotechnology , computational biology , gene , biochemistry
Summary The molecular mechanisms underlying the aging process are still unclear, but the clonal accumulation of mitochondrial deletion mutants is one of the prime candidates. An important question for the mitochondrial theory of aging is to discover how defective organelles might be selected at the expense of wild‐type mitochondria. We propose that mitochondrial fission and fusion events are of critical importance for resolving this apparent contradiction. We show that the occurrence of fusions removes the problems associated with the idea that smaller DNA molecules accumulate because they replicate in a shorter time – the survival of the tiny (SOT) hypothesis. Furthermore, stochastic simulations of mitochondrial replication, mutation and degradation show that two important experimental findings, namely the overall low mosaic pattern of oxidative phosphorylation (OXPHOS) impaired cells in old organisms and the distribution of deletion sizes, can be reproduced and explained by this hypothesis. Finally, we make predictions that can be tested experimentally to further verify our explanation for the age‐related accumulation of mitochondrial deletion mutants.