During spindle pole body (SPB) duplication, the new SPB is assembled at a distinct site adjacent to the old SPB. Using quantitative fluorescence methods, we studied the assembly and dynamics of the core structural SPB component Spc110p. The SPB core exhibits both exchange and growth in a cell cycle-dependent manner. During G1/S phase, the old SPB exchanges approximately 50% of old Spc110p for n...

Wee1 is a protein kinase that negatively regulates mitotic entry in G2 phase by suppressing cyclin B-Cdc2 activity, but its spatiotemporal regulations remain to be elucidated. We observe the dynamic behavior of Wee1 in Schizosaccharomyces pombe cells and manipulate its localization and kinase activity to study its function. At late G2, nuclear Wee1 efficiently suppresses cyclin B-Cdc2 around th...

Microtubule-organizing centers (MTOCs), known as centrosomes in animals and spindle pole bodies (SPBs) in fungi, are important for the faithful distribution of chromosomes between daughter cells during mitosis as well as for other cellular functions. The cytoplasmic duplication cycle and regulation of the Schizosaccharomyces pombe SPB is analogous to centrosomes, making it an ideal model to stu...

Accurate duplication of the Saccharomyces cerevisiae spindle pole body (SPB) is required for formation of a bipolar mitotic spindle. We identified mutants in SPB assembly by screening a temperature-sensitive collection of yeast for defects in SPB incorporation of a fluorescently marked integral SPB component, Spc42p. One SPB assembly mutant contained a mutation in a previously uncharacterized o...

T o prevent chromosome segregation errors, cytokinesis in Saccharomyces cerevisiae awaits the arrival of a spindle pole body (SPB) in the bud. On page 335 , Fraschini et al. show that this arrival is announced by the mother-bound SPB, which heralds the onset of cytokinesis and mitotic exit. Mitotic exit relies on a G-protein called Tem1, which activates the destruction of mitotic cyclins. As Te...

Routine sun protection is recommended to prevent skin cancer. Skin cancer prevention may be particularly important for individuals at greater risk, such as those with a family history of melanoma. Our aims were to examine the prevalence of sun-protective behavior (SPB) in unaffected first-degree relatives (FDR) of individuals diagnosed with melanoma and to examine the relationship between prote...

The regulation and timing of spindle pole body (SPB) duplication and maturation in fission yeast was examined by transmission electron microscopy. When cells are arrested at G1 by nitrogen starvation, the SPB is unduplicated. On release from G1, the SPBs were duplicated after 1-2 h. In cells arrested at S by hydroxyurea, SPBs are duplicated but not mature. In G1 arrest/release experiments with ...

The budding yeast Polo-like kinase Cdc5 is a key regulator of many mitotic events. Cdc5 coordinates its functions spatially and temporally by changing its localization during the cell cycle: Cdc5 is imported into the nucleus in G2 phase and released to the cytoplasm in anaphase, where it accumulates at the bud neck. Cdc5 also localizes to the spindle pole bodies (SPBs) from S phase until the en...

Recent papers have described new bioreactor designs. Most innovations addressed either oxygen transfer, shear induced by stirring, control of water activity in organic phase systems or waste biotreatment. Innovations made during the past year were reported in mainly three areas: bioreactor designs for increases in oxygen transfer and decreases in shear stress; bioreactors for two-phase reaction...