Isolation and characterization of new fission yeast cytokinesis mutants.
Schizosaccharomyces pombe is an excellent organism in which to study cytokinesis as it divides by medial fission using an F-actin contractile ring. To enhance our understanding of the cell division process, a large genetic screen was carried out in which 17 genetic loci essential for cytokinesis were identified, 5 of which are novel. Mutants identifying three genes, rng3(+), rng4(+), and rng5(+), were defective in organizing an actin contractile ring. Four mutants defective in septum deposition, septum initiation defective (sid)1, sid2, sid3, and sid4, were also identified and characterized. Genetic analyses revealed that the sid mutants display strong negative interactions with the previously described septation mutants cdc7-24, cdc11-123, and cdc14-118. The rng5(+), sid2(+), and sid3(+) genes were cloned and shown to encode Myo2p (a myosin heavy chain), a protein kinase related to budding yeast Dbf2p, and Spg1p, a GTP binding protein that is a member of the ras superfamily of GTPases, respectively. The ability of Spg1p to promote septum formation from any point in the cell cycle depends on the activity of Sid4p. In addition, we have characterized a phenotype that has not been described previously in cytokinesis mutants, namely the failure to reorganize actin patches to the medial region of the cell in preparation for septum formation.
Balasubramanian
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MK
Howard Hughes Medical Institute and Department of Cell Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
McCollum
D
D
Chang
L
L
Wong
K C
KC
Naqvi
N I
NI
He
X
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Sazer
S
S
Gould
K L
KL
D000199:Actins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins; D002455:Cell Division / Q000235:genetics*; D003001:Cloning, Molecular; D017931:DNA Primers; D004268:DNA-Binding Proteins; D005800:Genes, Fungal; D005838:Genotype; D008969:Molecular Sequence Data; D016296:Mutagenesis; D016133:Polymerase Chain Reaction; D011494:Protein Kinases / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D012568:Schizosaccharomyces / Q000166:cytology* / Q000235:genetics; D029702:Schizosaccharomyces pombe Proteins; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D000199:Actins; D018797:Cell Cycle Proteins; D017931:DNA Primers; D004268:DNA-Binding Proteins; D029702:Schizosaccharomyces pombe Proteins; C406818:cdt1 protein, S pombe; D011494:Protein Kinases; C113816:Sid2 protein, S pombe