Regulation of macronuclear DNA content in Chilodonella steini (Trithigmostoma steini)

Our presented studies describe a correlation between the content of macronuclear DNA in mother cells and their progeny after one cycle of cell growth in Chilodonella steini. We have found that the cells with a high level of macronuclear DNA produce daughter cells with a low DNA level and vice versa, and that the compensation of differences in the content of macronuclear DNA in sister cells requires several cell cycles. This compensation does not depend on the full replication rounds (as in the case of Tetrabymena) nor on the “increment” phenomenon (as in the case of Paramecium). Furthermore, we have found that in Chilodonella the length of the cell cycle is inversely proportional to the initial content of macronuclear DNA, i.e., the higher the Gl level, the shorter the cell cycle.