Alterations in the expression and activity of the centrosomal kinase, Aurora-A/STK15, affect genomic stability, disrupt the fidelity of centrosome duplication, and induce cellular transformation. A mitotic spindle-associated protein, astrin/DEEPEST, was identified as an Aurora-A interacting protein by a two-hybrid screen. Astrin and Aurora-A co-express at mitosis and co-localize to mitotic spin...

Architectural integrity of the mitotic spindle is required for efficient chromosome congression and accurate chromosome segregation to ensure mitotic fidelity. Tumour suppressor PTEN has multiple functions in maintaining genome stability. Here we report an essential role of PTEN in mitosis through regulation of the mitotic kinesin motor EG5 for proper spindle architecture and chromosome congres...

Mitotic catastrophe is the response of mammalian cells to mitotic DNA damage. It produces tetraploid cells with a range of different nuclear morphologies from binucleated to multimicronucleated. In response to DNA damage, checkpoints are activated to delay cell cycle progression and to coordinate repair. Cells in different cell cycle phases use different mechanisms to arrest their cell cycle pr...

The mechanism whereby the fusion of EWSR1 with the ETS transcription factor FLI1 contributes to malignant transformation in Ewing sarcoma remains unclear. We show that injection of human or zebrafish EWSR1/FLI1 mRNA into developing zebrafish embryos leads to mitotic defects with multipolar and disorganized mitotic spindles. Expression of human EWSR1/FLI1 in HeLa cells also results in mitotic de...

B-type cyclins promote mitotic entry and inhibit mitotic exit. In Saccharomyces cerevisiae, four B-type cyclins, Clb1-4, carry out essential mitotic roles, with substantial but incomplete overlap of function among them. Previous work in many organisms has indicated that B-type cyclin-dependent inhibition of mitotic exit imposes a requirement for mitotic destruction of B-type cyclins. For instan...

A normal consequence of mitosis in eukaryotes is the repression of transcription. Using Xenopus egg extracts shifted to a mitotic state by the addition of purified cyclin, we have for the first time been able to reproduce a mitotic repression of transcription in vitro. Active RNA polymerase III transcription is observed in interphase extracts, but strongly repressed in extracts converted to mit...

BACKGROUND Counting mitoses is subjective and time-consuming. The adjunctive diagnostic utility of a recently reported mitotic marker, phosphohistone H3 (PHH3), was investigated in gastrointestinal stromal tumors (GISTs). METHODS We reviewed 77 GISTs for several proliferative indices. These included the mitotic count per 50 high power fields (HPFs), the immunohistochemical Ki- 67 labeling ind...

Oncogene-induced senescence (OIS) is a tumor suppression mechanism that blocks cell proliferation in response to oncogenic signaling. OIS is frequently accompanied by multinucleation; however, the origin of this is unknown. Here, we show that multinucleate OIS cells originate mostly from failed mitosis. Prior to senescence, mutant H-RasV12 activation in primary human fibroblasts compromised mit...

Orderly progression through mitosis is essential to reduce segregation errors in the cell's genetic material. We have used a cytological screen to identify a mutant that progresses through mitosis aberrantly and have cloned the complementing gene, nimU, which encodes a protein related to Pot1 and other telomere end-binding proteins. We show that loss of nimU function leads to premature mitotic ...