High impact information on Prometaphase

• SNM and MNM colocalize along with a repetitive rDNA sequence known to function as an X-Y pairing site to nucleolar foci during meiotic prophase and to a compact structure associated with the X-Y bivalent during prometaphase I and metaphase I [1].
• Diazepam induces mitotic arrest at prometaphase by inhibiting centriolar separation [2].
• In vertebrate cells, arm cohesion is largely lost during prophase and prometaphase in order to facilitate sister chromatid resolution, whereas centromeric cohesion is preserved until the bipolar attachment of sister chromatids is established [3].
• Thus it appears that MEI-S332 assembles into a multimeric protein complex that localizes to centromeric regions during prometaphase and is required for the maintenance of sister-chromatid cohesion until anaphase, rather than its establishment in S phase [4].
• The abundant coiled-coil protein NuMA is located in the nucleus during interphase, but when the nuclear envelope disassembles in prometaphase it rapidly redistributes to the developing spindle poles [5].

Biological context of Prometaphase

• Through a dynein-dependent mechanism, DCLK regulates the formation of bipolar mitotic spindles and the proper transition from prometaphase to metaphase during mitosis [6].
• After local photoactivation of fluorescence by UV microbeam, we observed poleward movement of fluorescein-marked microtubules at a rate of 3 microns/min, similar to rates of chromosome movement and spindle elongation during prometaphase and anaphase [7].
• MAD2 staining was primarily observed on mitotic kinetochores that lacked attached microtubules; i.e., at prometaphase or when the microtubules were depolymerized with oryzalin [8].
• We show that Bub1 kinase activity is not required for phosphorylation of 3F3/2 epitopes at prophase/prometaphase, but is needed for 3F3/2 dephosphorylation at metaphase [9].
• Unlike other known guanine nucleotide exchange factors for Rho GTPases, ECT2 exhibits nuclear localization in interphase, spreads throughout the cytoplasm in prometaphase, and is condensed in the midbody during cytokinesis [10].

Anatomical context of Prometaphase

• Colcemid-treated prometaphase cells lysed into polymerization-competent tubulin develop large asters in the region of the centrioles and short tubules at kinetochores, making it unlikely that all microtubule formation in lysed cell preparations is dependent on tubulin addition to short tubule fragments [11].
• To analyze the assembly mechanism of the contractile ring, we microinjected a small amount of rhodamine-labeled phalloidin (rh-pha) or rhodamine-labeled actin (rh-actin) into dividing normal rat kidney cells. rh-pha was microinjected during prometaphase or metaphase to label actin filaments that were present at that stage [12].
• The fragmented and dispersed Golgi membranes in prometaphase and later stages of mitosis do not contain activated MEK1 [13].
• Here we show that human Plk1-deficient cells are unable to separate their centrosomes, fail to form a bipolar spindle, and undergo a Mad2/BubR1-dependent prometaphase arrest [14].
• The human Zwilch protein (hZwilch) coimmunoprecipitates with hZW10 and hROD from HeLa cell extracts and localizes to the kinetochores at prometaphase [15].

Associations of Prometaphase with chemical compounds

• Tubulin derivatized with photoactivatable fluorescein was microinjected into prometaphase LLC-PK and PtK1 cells and allowed to incorporate to steady-state [16].
• These include a drastic reduction of histone H3 phosphorylation at serine 10 (a target of Aurora B kinase), a pronounced attenuation at prometaphase and multipolar spindles [17].
• Formation of these conjugates occurs throughout G1 and S, but not in cells arrested in prometaphase by nocodazole [18].
• We demonstrate that lithium and two structurally distinct inhibitors of GSK-3 promote defects in microtubule length and chromosomal alignment during prometaphase [19].
• Starfish oocytes or eggs were inseminated at various times between first prometaphase and pronuclear stage, and were subsequently labeled with the thymidine analogue 5-bromo-2'-deoxyuridine (BrdU) in order to detect the onset of DNA synthesis phase (S phase) during the first cell cycle using a monoclonal antibody against BrdU [20].

Gene context of Prometaphase

• A functional conjugate of dynamitin with green fluorescent protein accumulates rapidly at prometaphase kinetochores, and subsequently migrates off kinetochores towards the poles during late prometaphase and metaphase [21].
• HOXC10 appears to be a new prometaphase target of the anaphase-promoting complex (APC), since its degradation coincides with cyclin A destruction and is suppressed by expression of a dominant-negative form of UbcH10, an APC-associated ubiquitin-conjugating enzyme [22].
• In mitotic cycles, however, Emi1 is destroyed in every pro-metaphase, and accordingly, it is unclear why Emi1 should be required for CSF activity, which is seen only in meta-II [23].
• During prophase and prometaphase, preceding kinetochore-microtubule attachment, Bub3 localizes to kinetochores [24].
• We show that full-length RAE1 and BUB1 proteins interact in mammalian cells and accumulate both at the kinetochores of prometaphase chromosomes [25].

Analytical, diagnostic and therapeutic context of Prometaphase

• Dynein/dynactin inhibition did not block chromosome congression to the spindle equator in prometaphase, or segregation to the poles in anaphase when the spindle checkpoint was inactivated by microinjection with Mad2 antibodies [26].
• Immunofluorescence analysis showed that LIMK1 was localized at cell-cell adhesion sites in interphase and prophase, redistributed to the spindle poles during prometaphase to anaphase, and accumulated at the cleavage furrow in telophase [27].
• Confocal microscopy further established that 85% of the mitotic cell population had prometaphase characteristics suggesting that P2P-R overexpression restricts mitotic progression at prometaphase [28].
• This system, which is based on fluorescence in situ hybridization combined with replicated prometaphase R-bands, allows the direct visualization of signals on R-banded prometaphases stained with propidium iodide and provides a more rapid and efficient method for genome mapping of cosmid clones [29].

References