RT Journal Article
SR Electronic
T1 Epistasis, aneuploidy, and gain-of-function mutations underlie the evolution of resistance to induced microtubule depolymerization
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.10.07.327759
DO 10.1101/2020.10.07.327759
A1 Mattia Pavani
A1 Paolo Bonaiuti
A1 Elena Chiroli
A1 Fridolin Gross
A1 Federica Natali
A1 Francesca Macaluso
A1 Adam Poti
A1 Sebastiano Pasqualato
A1 Simone Pompei
A1 Marco Cosentino-Lagomarsino
A1 Giulia Rancati
A1 David Szuts
A1 Andrea Ciliberto
YR 2020
UL http://biorxiv.org/content/early/2020/10/07/2020.10.07.327759.abstract
AB Microtubules, polymers of alpha- and beta-tubulin, are essential cellular components. When microtubule polymerization is hindered, cells are delayed in mitosis, but eventually they manage to proliferate with massive chromosome missegregation. Several studies have analyzed the first cell division upon microtubules impairing conditions. Here, we asked how cells cope on the long term. Taking advantage of mutations in beta-tubulin, we evolved in the lab for ∼150 generations 24 populations of yeast cells unable to properly polymerize microtubules. At the end of the evolution experiment, cells re-gained the ability to form microtubules, and were less sensitive to microtubule depolymerizing drugs. Whole genome sequencing allowed us to identify genes recurrently mutated (tubulins and kinesins) as well as the pervasive duplication of chromosome VIII. We confirmed that mutations found in these genes and disomy of chromosome VIII allow cells to compensate for the original mutation in beta-tubulin. The mutations we identified were mostly gain-of-function, likely re-allowing the proper use of the mutated form of beta-tubulin. When we analyzed the temporal order of mutations leading to resistance in independent populations, we observed multiple times the same series of events: disomy of chromosome VIII followed by one additional adaptive mutation in either tubulins or kinesins. Analyzing the epistatic interactions among different mutations, we observed that some mutations benefited from the disomy of chromosome VIII and others did not. Given that tubulins are highly conserved among eukaryotes, our results are potentially relevant for understanding the emergence of resistance to drugs targeting microtubules, widely used for cancer treatment.Competing Interest StatementThe authors have declared no competing interest.