(158j) Nuclear Size Changes Caused By Local Motion of Cell Boundaries Unfold the Nuclear Lamina and Dilate Chromatin and Intranuclear Bodies

Katiyar, A., University of Florida
Dickinson, R., University of Florida
Tocco, V. J. Jr., University of Florida
Li, Y., University of Florida
Aggarwal, V., University of Florda
Tamashunas, A., University of Florida
Lele, T., University of Florida
The mechanisms by which mammalian nuclear shape and size are established in cells, and become abnormal in disease states are not understood. Here, we tracked motile cells that underwent systematic changes in cell morphology as they moved from 1-D to 2-D micro-patterned adhesive domains. Motion of the cell boundaries during cell motility caused a dynamic and systematic change in nuclear volume. Short time scales (~1 h) distinguished the dilation of the nucleus from the familiar increase that occurs during the cell cycle. Nuclear volume was systematically different between cells cultured in 3-D, 2-D and 1-D environments. Dilation of the nuclear volume was accompanied by dilation of chromatin, a decrease in the number of folds in the nuclear lamina, and an increase in nucleolar volume. Treatment of 2-D cells with non-muscle myosin-II inhibitors decreased cell volume, and proportionately caused a decrease in nuclear volume. These data suggest that nuclear size changes during cell migration may potentially impact gene expression through the modulation of intranuclear structure.