Mad1p, a component of the spindle assembly checkpoint in fission yeast, suppresses a novel septation-defective mutant, sun1, in a cell-division cycle.
To enhance our understanding of the cytokinesis, we have carried out a genetic screen for temperature-sensitive Schizosaccharomyces pombe mutants that show defects in septum formation and cell division. Here we present the isolation and characterization of a new temperature-sensitive mutant, sun1 (septum uncontrolled), which undergoes uncontrolled septation during cell-division cycle at restrictive temperature (37 degrees C). In sun1 mutant, the actin ring and septum are positioned at random locations and angles, and the nuclear division cycle continues. These observations suggest that the sun1 gene product is required for the proper placement of the actin ring as well as precise septation. In a screen for the sun1(+) gene to complement the sun1 mutant, we have isolated a mad1(+) (mitotic arrest deficient) gene, which encodes a component of the spindle checkpoint in the cell-division cycle. Analysis of crossing the sun1 cell with the mad1(+) null mutant indicates that mad1(+) suppresses the sun1 mutant defective in controlled septation in a cell-division cycle.
Kim
In G
IG
Department of Molecular Biology, Graduate School of Biotechnology, Korea University, 136-701, Seoul, South Korea.
Rhee
Dong K
DK
Jeong
Jae W
JW
Kim
Seong C
SC
Won
Misun
M
Lee
JooHun
J
Song
Ki W
KW
Kim
Hyong B
HB
D000199:Actins / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D002455:Cell Division / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics* / Q000302:isolation & purification; D016601:RNA-Binding Proteins; D012097:Repressor Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D012568:Schizosaccharomyces / Q000166:cytology / Q000235:genetics* / Q000254:growth & development; D029702:Schizosaccharomyces pombe Proteins; D008941:Spindle Apparatus / Q000378:metabolism; D013696:Temperature
D000199:Actins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; C501382:MAD1 protein, S cerevisiae; D009687:Nuclear Proteins; D010750:Phosphoproteins; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; D029702:Schizosaccharomyces pombe Proteins; C501383:mad1 protein, S pombe; C498507:pus1 protein, S pombe