An identical ANOVA for spindle activity also revealed a significant main effect for HEMISPHERE (F 1,16) = 9.466, p = 0.008) and significant interactions for TYPE × FRONT/CENT (F 1,16) = 14.671, p = 0.002) as well for TYPE × HEMISPHERE (F 1,16) = 7.627, p = 0.015) indicating stronger spindle activity on the left hemisphere and on frontal regions.
The phenotype of many of these alleles is as severe as the strongest spindle-E phenotype, whereas alleles with mutations in other regions of Spindle-E did not affect these processes as much.
Staining for GFAP showed variable immunostaining in the neoplastic cells, i.e. weak and sparse in Antoni type B patterns and moderate to strong in spindle-shaped cells from the Antoni type A patterns, including intravascular located neoplastic cells (Fig. 2).
This hexagonal arrangement maximizes the interactions between a microtubule and its neighbors, which makes the spindle stronger and prevents it from buckling under the physical forces that act on it.
Surprisingly, whereas the majority of WT spindles exhibited strong D-TACC localisation, ∼85% of mutant spindles had weak or no D-TACC staining (Fig. 5D; p≤0.001).
Furthermore, there is strong activation of the spindle checkpoint complex (MD2a, MD2b and BUBR1), the cellular sensing system that normally prevents premature separation of chromosomes.
Strong dynein inhibition causes spindle defects.
Immunophenotyping, confirmed by biochemical analyses, showed a modulation of c-Kit expression which was faint in the spindle and strong in the epithelial component, respectively.
Furthermore, CALMODULIN, a calcium-binding protein known to interact with PERICENTRIN and ASPM, also exhibits strong staining at the spindle poles [ 91].
