The Effects of an Increased Amount of Mitochondrial DNA on the Yeast Metabolic Cycle

Abstract

When prototrophic yeast cells undergo continuous growth in nutrient-limited conditions, they experience robust metabolic oscillations. Additionally, the processes of metabolism in yeast cells have been shown to be coordinated with cell division; cell division can only occur in certain phases of the metabolic cycle. It has been hypothesized that certain mutations that influence the rate of cell division may also affect yeast metabolic oscillations. Abf2p is a mitochondrial DNA maintenance protein; overexpression of Abf2p increases the rate of cell division, however, the effects of the overexpression of Abf2p on yeast metabolism are not known. Using a chemostat apparatus, metabolic oscillations, in terms of fluctuating dissolved oxygen concentrations, of Abf2p were obtained. Remarkably, the period of the metabolic oscillations of cells over-expressing Abf2p was more variable, but always longer than the period of wild-type cells. This was due to a clear expansion of the reductive phase. If the role of Abf2p in promoting cell division can be determined, a possible mechanism of controlling cell division may be established