Cell-Cycle Independent Chromosome Condensation in Schizosaccharomyces pombe Induced by High Hydrostatic Pressure Treatment

Abstract

We exposed Schizosaccharomyces pombe to high hydrostatic pressure treatment (HPT) of 75 MPa at 28 °C for 30 min and then observed that the DAPI-stained chromosomal DNA had shrunk compactly. We termed this phenomenon HPT-induced chromosome condensation (HPT-CC). HPT did not significantly decrease viability. The condensed state was released when HPT cells were cultured at 28 °C for 30 min. The condensation was not caused by shrinking of the nuclear envelope, which was visualized by YFP-tagged importin α. HPT-CC was cell cycle independent, because it was observed in almost all randomly cultured cells. The condensin complex (Cut3, Cut14, and three other proteins) is responsible for cell cycle dependent CC. Studies with Cut3-YFP and ts mutants of Cut3 and Cut14 confirmed that HPT-CC was independent of condensin molecules. HPT-CC was also observed in Saccharomyces cerevisiae. HPT-CC appears likely to be a temporal stress response to high hydrostatic pressure found at least in yeasts.