Effect of PRAK gene knockout on the proliferation of mouse embryonic fibroblasts

Abstract

p38 regulated/activated protein kinase (PRAK) plays a key role in cell senescence and tumor suppression. The aim of this study was to investigate if PRAK had effect on cell proliferation. The growth of PRAK^+/+ and PRAK^{−/−} mouse embryonic fibroblast (MEF) cells was measured by methylthiazoletetrazolium (MTT) colorimetric assay, and the proportion of the cell number in different phases of the cell cycle was analyzed by flow cytometry. The growth curves showed that the growth rate was notably decreased, and cell double time was elongated in PRAK^{−/−} cells; moreover, the number of PRAK^{−/−} cells was decreased by 44.5% compared with that of PRAK^+/+ cells cultured for 96h, suggesting that G₂/M transition is inhibited in PRAK^{−/−} cells. Meanwhile, G₁/S transition was also inhibited in PRAK^{−/−} cells, observed with flow cytometry analysis. The ratios of G₀/G₁, G₂/M, and S phases of PRAK^+/+ cells were 44.9%, 12.2%, and 42.9%, respectively, while those of PRAK^{−/−} cells were 55.3%, 7.3%, and 37.4%, respectively. There were 23.1% increase and 12.7% decrease of the number of PRAK^{−/−} cells in G₁ and S phases comparison with that of PRAK^+/+ cells, respectively. Taken together, PRAK gene knockout in MEF cells leads to cell cycle arrest and proliferation inhibition.

Keywords

p38 regulated/activated protein kinase / gene knockout / cell cycle / cell proliferation