Mph1, a member of the Mps1-like family of dual specificity protein kinases, is required for the spindle checkpoint in S. pombe.

The spindle assembly checkpoint pathway is not essential for normal mitosis but ensures accurate nuclear division by blocking the metaphase to anaphase transition in response to a defective spindle. Here, we report the isolation of a new spindle checkpoint gene, mph1 (Mps1p-like pombe homolog), in the fission yeast Schizosaccharomyces pombe, that is required for checkpoint activation in response to spindle defects. mph1 functions upstream of mad2, a previously characterized component of the spindle checkpoint. Overexpression of mph1, like overexpression of mad2, mimics activation of the checkpoint and imposes a metaphase arrest. mph1 protein shares sequence similarity with Mps1p, a dual specificity kinase that functions in the spindle checkpoint of the budding yeast Saccharomyces cerevisiae. Complementation analysis demonstrates that mph1 and Mps1p are functionally related. They differ in that Mps1p, but not mph1, has an additional essential role in spindle pole body duplication. We propose that mph1 is the MPS1 equivalent in the spindle checkpoint pathway but not in the SPB duplication pathway. Overexpression of mad2 does not require mph1 to impose a metaphase arrest, which indicates a mechanism of spindle checkpoint activation other than mph1/Mps1p kinase-dependent phosphorylation. In the same screen which led to the isolation of mad2 and mph1, we also isolated dph1, a cDNA that encodes a protein 46% identical to an S. cerevisiae SPB duplication protein, Dsk2p. Our initial characterization indicates that S.p. dph1 and S.c. DSK2 are functionally similar. Together these results suggest that the budding and fission yeasts share common elements for SPB duplication, despite differences in SPB structure and the timing of SPB duplication relative to mitotic entry.

[1]  F. Bischoff,et al.  The identification of cDNAs that affect the mitosis-to-interphase transition in Schizosaccharomyces pombe, including sbp1, which encodes a spi1p-GTP-binding protein. , 1998, Genetics.

[2]  J. McIntosh,et al.  The spindle pole body of Schizosaccharomyces pombe enters and leaves the nuclear envelope as the cell cycle proceeds. , 1997, Molecular biology of the cell.

[3]  T. Davis,et al.  Calmodulin localizes to the spindle pole body of Schizosaccharomyces pombe and performs an essential function in chromosome segregation. , 1997, Journal of cell science.

[4]  S. Sazer,et al.  The Schizosaccharomyces pombe spindle checkpoint protein mad2p blocks anaphase and genetically interacts with the anaphase-promoting complex. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[5]  N. Cole,et al.  Saccharomyces cerevisiae genes required in the absence of the CIN8-encoded spindle motor act in functionally diverse mitotic pathways. , 1997, Molecular biology of the cell.

[6]  Stephen S. Taylor,et al.  Kinetochore Localization of Murine Bub1 Is Required for Normal Mitotic Timing and Checkpoint Response to Spindle Damage , 1997, Cell.

[7]  R. Nicklas,et al.  Tension-sensitive kinetochore phosphorylation and the chromosome distribution checkpoint in praying mantid spermatocytes. , 1997, Journal of cell science.

[8]  D. Burke,et al.  Cdc55p, the B-type regulatory subunit of protein phosphatase 2A, has multiple functions in mitosis and is required for the kinetochore/spindle checkpoint in Saccharomyces cerevisiae , 1997, Molecular and cellular biology.

[9]  M. Kirschner,et al.  Anaphase initiation in Saccharomyces cerevisiae is controlled by the APC-dependent degradation of the anaphase inhibitor Pds1p. , 1996, Genes & development.

[10]  A. Murray,et al.  The spindle assembly checkpoint. , 1996, Current opinion in cell biology.

[11]  V. Simanis,et al.  The fission yeast dma1 gene is a component of the spindle assembly checkpoint, required to prevent septum formation and premature exit from mitosis if spindle function is compromised. , 1996, The EMBO journal.

[12]  Andrew W. Murray,et al.  Association of Spindle Assembly Checkpoint Component XMAD2 with Unattached Kinetochores , 1996, Science.

[13]  R. Benezra,et al.  Identification of a Human Mitotic Checkpoint Gene: hsMAD2 , 1996, Science.

[14]  T. Hunt,et al.  The role of proteolysis in cell cycle progression in Schizosaccharomyces pombe. , 1996, The EMBO journal.

[15]  A. Murray,et al.  Activation of the Budding Yeast Spindle Assembly Checkpoint Without Mitotic Spindle Disruption , 1996, Science.

[16]  S. Biggins,et al.  Yeast ubiquitin-like genes are involved in duplication of the microtubule organizing center , 1996, The Journal of cell biology.

[17]  Tim Hunt,et al.  Cut2 proteolysis required for sister-chromatid separation in fission yeast , 1996, Nature.

[18]  Eric L. Weiss,et al.  The Saccharomyces cerevisiae spindle pole body duplication gene MPS1 is part of a mitotic checkpoint , 1996, The Journal of cell biology.

[19]  T. Shibata,et al.  Role of gamma-tubulin in mitosis-specific microtubule nucleation from the Schizosaccharomyces pombe spindle pole body. , 1996, Journal of cell science.

[20]  A. Murray,et al.  Mad1p, a phosphoprotein component of the spindle assembly checkpoint in budding yeast , 1995, The Journal of cell biology.

[21]  G. Gorbsky,et al.  Kinetochore chemistry is sensitive to tension and may link mitotic forces to a cell cycle checkpoint , 1995, The Journal of cell biology.

[22]  K Nasmyth,et al.  Cdc6 is an unstable protein whose de novo synthesis in G1 is important for the onset of S phase and for preventing a ‘reductional’ anaphase in the budding yeast Saccharomyces cerevisiae. , 1995, The EMBO journal.

[23]  M. Yanagida,et al.  The product of the spindle formation gene sad1+ associates with the fission yeast spindle pole body and is essential for viability , 1995, The Journal of cell biology.

[24]  M. Kirschner,et al.  A 20s complex containing CDC27 and CDC16 catalyzes the mitosis-specific conjugation of ubiquitin to cyclin B , 1995, Cell.

[25]  Kim Nasmyth,et al.  Genes involved in sister chromatid separation are needed for b-type cyclin proteolysis in budding yeast , 1995, Cell.

[26]  Eric L. Weiss,et al.  Yeast spindle pole body duplication gene MPS1 encodes an essential dual specificity protein kinase. , 1995, The EMBO journal.

[27]  R. Nicklas,et al.  Mitotic forces control a cell-cycle checkpoint , 1995, Nature.

[28]  B. Roberts,et al.  The Saccharomyces cerevisiae checkpoint gene BUB1 encodes a novel protein kinase. , 1994, Molecular and cellular biology.

[29]  A. Murray,et al.  A MAP kinase-dependent spindle assembly checkpoint in Xenopus egg extracts , 1994, Cell.

[30]  W. Ricketts,et al.  Differential expression of a phosphoepitope at the kinetochores of moving chromosomes , 1993, The Journal of cell biology.

[31]  Andrew W. Murray,et al.  Anaphase is initiated by proteolysis rather than by the inactivation of maturation-promoting factor , 1993, Cell.

[32]  A. Reymond,et al.  The S. pombe cdc16 gene is required both for maintenance of p34cdc2 kinase activity and regulation of septum formation: a link between mitosis and cytokinesis? , 1993, The EMBO journal.

[33]  S. Forsburg Comparison of Schizosaccharomyces pombe expression systems. , 1993, Nucleic acids research.

[34]  K Nasmyth,et al.  Destruction of the CDC28/CLB mitotic kinase is not required for the metaphase to anaphase transition in budding yeast. , 1993, The EMBO journal.

[35]  Hans Lehrach,et al.  High resolution cosmid and P1 maps spanning the 14 Mb genome of the fission yeast S. pombe , 1993, Cell.

[36]  K. Maundrell Thiamine-repressible expression vectors pREP and pRIP for fission yeast. , 1993, Gene.

[37]  M. Snyder,et al.  Chromosome segregation in yeast. , 1993, Annual review of microbiology.

[38]  G. Mills,et al.  Expression of TTK, a novel human protein kinase, is associated with cell proliferation. , 1992, The Journal of biological chemistry.

[39]  T. Pawson,et al.  Multiple cDNAs encoding the esk kinase predict transmembrane and intracellular enzyme isoforms , 1992, Molecular and cellular biology.

[40]  Andrew W. Murray,et al.  Feedback control of mitosis in budding yeast , 1991, Cell.

[41]  B. Roberts,et al.  S. cerevisiae genes required for cell cycle arrest in response to loss of microtubule function , 1991, Cell.

[42]  M. Winey,et al.  MPS1 and MPS2: novel yeast genes defining distinct steps of spindle pole body duplication , 1991, The Journal of cell biology.

[43]  S. Moreno,et al.  Molecular genetic analysis of fission yeast Schizosaccharomyces pombe. , 1991, Methods in enzymology.

[44]  M. Yanagida,et al.  The transition of cells of the fission yeast beta-tubulin mutant nda3-311 as seen by freeze-substitution electron microscopy. Requirement of functional tubulin for spindle pole body duplication. , 1990, Journal of cell science.

[45]  Sergio Moreno,et al.  Regulation of p34cdc2 protein kinase during mitosis , 1989, Cell.

[46]  K. Gull,et al.  Definition of individual components within the cytoskeleton of Trypanosoma brucei by a library of monoclonal antibodies. , 1989, Journal of cell science.

[47]  R. Sikorski,et al.  A system of shuttle vectors and yeast host strains designed for efficient manipulation of DNA in Saccharomyces cerevisiae. , 1989, Genetics.

[48]  M. Yamamoto Fission yeast. , 1989, Biotechnology.

[49]  I. Hagan,et al.  The use of cell division cycle mutants to investigate the control of microtubule distribution in the fission yeast Schizosaccharomyces pombe. , 1988, Journal of cell science.

[50]  G. Fink,et al.  KAR1, a gene required for function of both intranuclear and extranuclear microtubules in yeast , 1987, Cell.

[51]  T. Toda,et al.  The NDA3 gene of fission yeast encodes β-tubulin: A cold-sensitive nda3 mutation reversibly blocks spindle formation and chromosome movement in mitosis , 1984, Cell.

[52]  H. Eipel,et al.  Microbial determinations by flow cytometry. , 1979, Journal of general microbiology.

[53]  S. Phillips,et al.  INDEPENDENCE OF CENTRIOLE FORMATION AND DNA SYNTHESIS , 1973, The Journal of cell biology.