A Balance between Nuclear and Cytoplasmic Volumes Controls Spindle Length
Fig 4
Overexpression of TPX2 has no effect on spindle length.
(A) Left panel: Blastomeres of mouse 2-cell embryos were microinjected with cRNAs encoding Histone-H2B fused to mCherry and Tubulin fused to EGFP with (bottom) or without (top) cRNA encoding TPX2 protein. Following microinjection, one of the two blastomeres in each embryo was enucleated and then both fused together. Right panel shows representative movie frames from time lapse imaging of each cell type in interphase and in mitosis, chromosomes are in red, spindle is in green, scale bar represents 10 μm. (B) In some experiments, TXP2 was used with fluorescent tag. Representative images of cells before (left panels, 10 min) and during NEBD (right panel, 0 min) show the nuclear localization of exogenous TPX2 in interphase and its relocalization to the cytoplasm before spindle assembly. Chromosomes are in red, TPX2 in cyan, scale bar represents 10 μm. (C) The length of the spindle in 2 fused enucleated cells with overexpressed TPX2 (41.14 ± 4.07 μm, n = 18) was not significantly different (p = 0.3961) compared to the length of the spindle in 2 fused enucleated cells (40.14 ± 2.64 μm, n = 17).
