Showing papers by "Kathleen L. Gould published in 1997"
TL;DR: Study of S. pombe mutants has begun to shed light on how septum formation and cytokinesis are regulated both spatially and temporally, to achieve proper co-ordination with mitosis.
Abstract: If cell division is to produce two daughter cells that are viable, faithful copies of the parent cell, the landmark events of the cell division cycle, S phase, mitosis, and cytokinesis, must be executed in the correct order and with high fidelity. Though considerable advances have been made toward understanding the mechanisms that control the onset of S phase and mitosis, regulation of the events that occur at the end of the cell cycle, such as the reorganization of the cytoskeleton and the initiation of cell separation or cytokinesis, are less well understood. The fission yeast Schizosaccharomyces pombe provides a simple eukaryotic model for the study of cytokinesis. S. pombe cells are rod shaped, grow mainly by elongation at their ends, and divide by binary fission after forming a centrally placed division septum. Study of S. pombe mutants has begun to shed light on how septum formation and cytokinesis are regulated both spatially and temporally, to achieve proper co-ordination with mitosis. Some of the genes defined by these mutants have been functionally conserved through eukaryotic evolution, suggesting that aspects of this control will be common to all eukaryotic cells.
185 citations
TL;DR: This chapter discusses the cytokinesis in fission yeast Schizosaccharomyces pombe, which is particularly well suited for the study of cytokineis, because like higher eukaryotes, S. pom be divides by medial fission through the use of an F-actin contractile ring.
Abstract: Publisher Summary This chapter discusses the cytokinesis in fission yeast Schizosaccharomyces pombe. The process of cytokinesis in animal cells has been the subject of a large number of ingenious embryological experiments. While these experiments have revealed a great deal at a mechanistic level about what factors influence cleavage furrow formation, much less is known at a molecular level. Because much of the current understanding of the eukaryotic cell cycle at a molecular level is derived from genetic studies in the two yeasts, Saccharomyces cerevisiae and Schizosaccharomyces pombe, it seems likely that the study of cytokinesis in yeast will also be revealing. Schizosaccharomyces pombe is particularly well suited for the study of cytokinesis, because like higher eukaryotes, S. pombe divides by medial fission through the use of an F-actin contractile ring. The actin cytoskeleton in fission yeast contains three major types of actin structures.
114 citations
TL;DR: It is concluded that Dim1p plays a fundamental, evolutionarily conserved role as a protein essential for entry into mitosis as well as for chromosome segregation during mitosis.
Abstract: In a screen for second site mutations capable of reducing the restrictive temperature of the fission yeast mutant cdc2-D217N, we have isolated a novel temperature-sensitive mutant, dim1-35. When shifted to restrictive temperature, dim1-35 mutant cells arrest before entry into mitosis or proceed through mitosis in the absence of nuclear division, demonstrating an uncoupling of proper DNA segregation from other cell cycle events. Deletion of dim1 from the Schizosaccharomyces pombe genome produces a lethal G2 arrest phenotype. Lethality is rescued by overexpression of the mouse dim1 homolog, mdim1. Likewise, deletion of the Saccharomyces cerevisiae dim1 homolog, CDH1, is lethal. Both mdim1 and dim1(+) are capable of rescuing lethality in the cdh1::HIS3 mutant. Although dim1-35 displays no striking genetic interactions with various other G2/M or mitotic mutants, dim1-35 cells incubated at restrictive temperature arrest with low histone H1 kinase activity. Morevoer, dim1-35 displays sensitivity to the microtubule destabilizing drug, thiabendazole (TBZ). We conclude that Dim1p plays a fundamental, evolutionarily conserved role as a protein essential for entry into mitosis as well as for chromosome segregation during mitosis. Based on TBZ sensitivity and failed chromosome segregation in dim1-35, we further speculate that Dim1p may play a role in mitotic spindle formation and/or function.
43 citations
TL;DR: It is suggested that wat1+ is required directly or indirectly for polarized cell growth in S. pombe and a functional, epitope-tagged, version of Wat1p can be overproduced without inducing alterations in cell morphology.
Abstract: The organization of the actin cytoskeleton plays an integral role in cell morphogenesis of all eukaryotes. We have isolated a temperature-sensitive mutant in Schizosaccharomyces pombe, wat1-1, in which acting patches are delocalized, resulting in an elliptically shaped cell phenotype. Molecular cloning and DNA sequencing of wat1+ showed that the gene encodes a 314 residue protein containing WD-40 repeats. Cells lacking wat1+ are slow growing but viable at 25 degrees C and temperature-sensitive for growth above 33 degrees C. At restrictive temperature, wat1-d strains are phenotypically indistinguishable from wat1-1. When combined with a deletion for the wat1+ gene, cdc mutants failed to elongate at restrictive temperature and exhibited alterations in actin patch localization. This analysis suggests that wat1+ is required directly or indirectly for polarized cell growth in S. pombe. Wat1p and a functional, epitope-tagged, version of Wat1p can be overproduced without inducing alterations in cell morphology.
19 citations