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Fulleborn, J. A.

Publications and source records attributed to Fulleborn, J. A..

2 recordsLinked to original sources

Cell cycle dynamics of redox state and lipid metabolism in S. cerevisiae, S. pombe and murine leukaemia cells

Coordination of metabolism, cell growth and cell division is essential to life. Recent single-cell measurements in S. cerevisiae have shown that metabolic processes and the cellular redox state are dynamic along the cell cycle. However, it is unknown whether similar metabolic oscillations also occur in other organisms. Until now, the dynamics of metabolism in other eukaryotes have predominantly been studied in cell cycle synchronised populations. Since cell cycle synchronisation methods can perturb metabolism, they may also introduce artefacts in the recorded dynamics. Here, we performed time-lapse microscopy analyses of exponentially growing single cells of the budding yeast S. cerevisiae, the fission yeast S. pombe and murine leukaemia L1210 cells. Measuring the NAD(P)H autofluorescence and the cell surface area growth rate in unsynchronised cells, we discovered oscillations along the cell cycle of the cellular redox state and lipid metabolism, respectively. Thus, our work shows that metabolism is dynamic along the cell cycle of these three evolutionarily distant eukaryotic organisms. This finding suggests that such metabolic oscillations could be a conserved characteristic among eukaryotes.

cell biology↗

OsTIR1F74G Expression Controls Basal and Auxin-Induced Degradation Rates of the AID System in Yeast

The auxin-inducible degron (AID) system has been widely used to conditionally and dynamically deplete proteins in yeast. In this system, the plant hormone auxin promotes OsTIR1-mediated degradation of proteins carrying an auxin-inducible degron tag. However, "basal" degradation of AID-tagged proteins in the absence of auxin has hampered work with essential proteins due to defective or non-viable strains. A second-generation AID system based on the OsTIRF47G mutant was recently introduced to overcome the limitations of basal degradation in budding yeast. However, it remained unclear to what extent the use of OsTIRF47G eliminates basal degradation and how it impacts auxin-induced degradation. Here, by performing a quantitative characterization of the basal and auxin-induced degradation dynamics using OsTIR1F74G in budding yeast, we find that basal degradation is still detectable and that it depends on OsTIR1F74G expression levels. We show that also the auxin-induced degradation rates and auxin-induced steady-state concentrations of AID-tagged proteins depend on OsTIR1F74G expression levels, in addition to the type of auxin used. Lastly, we showcase how increased basal degradation of AID-tagged functional proteins can impair cell growth and lead to unwanted phenotypes. We anticipate that our findings will guide future applications of the AID system in budding yeast by helping researchers select appropriate OsTIR1F74G expression levels, particularly in studies focused on precise control of degradation dynamics.

molecular biology↗