The extent and pattern of the rearrangements of microtubule arrays in interphase and mitotic PtK2 cells treated with deuterium oxide (2H2O) were evaluated using light, immunofluorescence and electron microscopy. Combined labelling with anti-tubulin antibodies and staining with a DNA-specific fluorochrome revealed that 2H2O influences the reassembly of the cytoplasmic microtubule complex (CMTC) ...

We have identified an F-actin cytoskeletal network that remains throughout interphase, mitosis, and cytokinesis of higher plant endosperm cells. Fluorescent labeling was obtained using actin monoclonal antibodies and/or rhodamine-phalloidin. Video-enhanced microscopy and ultrastructural observations of immunogold-labeled preparations illustrated microfilament-microtubule co-distribution and int...

γ-Tubulin plays a universal role in microtubule nucleation from microtubule organizing centers (MTOCs) such as the animal centrosome and fungal spindle pole body (SPB). γ-Tubulin functions as a multiprotein complex called the γ-tubulin complex (γ-TuC), consisting of GCP1-6 (GCP1 is γ-tubulin). In fungi and flies, it has been shown that GCP1-3 are core components, as they are indispensable for γ...

N ayak et al. reveal that ␥-tubulin, better known as a microtubule-nucleating protein, controls the cell cycle by switching off a key mitotic regulator during interphase. Evidence suggests that ␥-tubulin has microtubule-independent functions: a ␥-tubulin mutant called mipAD159 causes mitotic defects in Aspergillus nidulans, even though the fungus continues to assemble mitotic spindles and inter...

The specificity of the staining of CREST scleroderma patient serum was investigated by immunofluorescence and immunoelectron microscopy. The serum was found to stain the centromere region of mitotic chromosomes in many mammalian cell types by immunofluorescence. It also localized discrete spots in interphase nuclei which we have termed "presumptive kinetochores." The number of presumptive kinet...

The reorganization from a radial [corrected] interphase microtubule (MT) network into a bipolar spindle at the onset of mitosis involves a dramatic change in MT dynamics. Microtubule-associated proteins (MAPs) and other factors are thought to regulate MT dynamics both in interphase and in mitosis. In this study we report the purification and functional in vitro characterization of a 230-KD MAP ...

In vitro reconstitution is the fundamental test for identification of the core components of a biological process. In this issue, Moriwaki and Goshima (2016. J. Cell Biol. https://doi.org/10.1083/jcb.201604118) reconstitute all phases of microtubule dynamics through the inclusion of five key regulators and demonstrate that Polo kinase activity shifts the system from an interphase mode into an e...

The CDC25 cell cycle regulators are promising targets for new pharmacologic approaches in cancer therapy. Inhibitory compounds such as BN82685 have proven to be effective in specifically targeting CDC25 in cultured cells and in inhibiting tumor cell growth. Here, we report that BN82685 impairs microtubule dynamic instability and alters microtubule organization and assembly at the centrosome in ...

The human M phase phosphoprotein 1 (MPP1), previously identified through a screening of a subset of proteins specifically phosphorylated at the G2/M transition (Matsumoto-Taniura, N., Pirollet, F., Monroe, R., Gerace, L., and Westendorf, J. M. (1996) Mol. Biol. Cell 7, 1455-1469), is characterized as a plus-end-directed kinesin-related protein. Recombinant MPP1 exhibits in vitro microtubule-bin...

The conserved Prp19 (pre-RNA processing 19) complex is required for pre-mRNA splicing in eukaryotic nuclei. Recent RNAi screens indicated that knockdown of Prp19 complex subunits strongly delays cell proliferation. Here we show that knockdown of the smallest subunit, BCAS2/Spf27, destabilizes the entire complex and leads to specific mitotic defects in human cells. These could result from splici...