Mitotic Spindle in HeLa Cell Rotates According to the Local Temperature Gradient

Abstract

The temperature gradient is present at the surface of living organisms, and also inside of the bodies. Each cell has to adapt to the change in the temperature over short and long timescale to precisely perform cellular processes. Ishizaka has reported that the position of mitotic spindle in grasshopper spermatocyte shifted under temperature gradient, resulting in unequal cell division (Ishizaka, S. Dev. Growth Differ. 11, 179–85, 1969). Here we created the temperature gradient within single HeLa cells in mitosis, and show that the mitotic spindle is rearranged so that the pole-to-pole axis is to be perpendicular to the gradient. Our results suggest that one of the key components of this response is the temperature-dependent polymerization dynamics of microtubule cytoskeleton, a scaffold of the spindle. Then, we further confirmed that the elongation rate was increased according to the temperature gradient in the spindle. Due to this anisotropy in the astral microtubules, these microtubules could produce pushing and pulling forces such that the pole closer to the heat source can move down the slope of the temperature until the temperature at this pole is equal to that at another.