The effects of nucleotide import into the mitochondrion on the mtDNA replication rate.

Each point is the mean mtDNA replication rate from 100 simulations with different randomly chosen initial concentrations of deoxynucleosides and deoxynucleotides. The X-axis represents the total amount of additional deoxynucleosides or deoxynucleotides supplied (sum total of equal amounts for each of the four species). Additional supply of dN, dNMP, dNDP or dNTP were simulated separately. The dNTP output from mitochondrial salvage alone is insufficient to support a replication rate of as long as 10 hours. Additional supply of dNs and dNMPs was insufficient to support a replication duration of 2 hours indicating that additional dNDPs or dNTPs are essential. The results were essentially identical for supply of either dNDPs or dNTPs.