Sucl+ encodes a predicted 13-kilodalton protein that is essential for cell viability and is directly involved in the division cycle of Schizosaccharomyces pombe

1987 ◽  
Vol 7 (1) ◽  
pp. 504-511 ◽  
Author(s):  
J Hindley ◽  
G Phear ◽  
M Stein ◽  
D Beach
Keyword(s):  
Cell Division ◽  
Schizosaccharomyces Pombe ◽  
Cell Cycle Control ◽  
Temperature Sensitive ◽  
Base Pairs ◽  
Direct Role ◽  
Protein Coding ◽  
Dna Fragment ◽  
Rna Transcript ◽  
Translational Product

Sucl+ was originally identified as a DNA sequence that, at high copy number, rescued Schizosaccharomyces pombe strains carrying certain temperature-sensitive alleles of the cdc2 cell cycle control gene. We determined the nucleotide sequence of a 1,083-base-pair Sucl+ DNA fragment and S1 mapped its 866-nucleotide RNA transcript. The protein-coding sequence of the gene is interrupted by two intervening sequences of 115 and 51 base pairs. The predicted translational product of the gene is a protein of 13 kilodaltons. A chromosomal gene disruption of Sucl+ was constructed in a diploid S. pombe strain. Germinating spores carrying a null allele of the gene were capable of very limited cell division, following which many cells became highly elongated. The Sucl+ gene was also strongly overexpressed under the control of a heterologous S. pombe promoter. Overexpression of Sucl+ is not lethal but causes a division delay such that cells are approximately twice the normal length at division. These data suggest that Sucl+ encodes a protein which plays a direct role in the cell division cycle of S. pombe.

scholarly journals Sucl+ encodes a predicted 13-kilodalton protein that is essential for cell viability and is directly involved in the division cycle of Schizosaccharomyces pombe.

1987 ◽  
Vol 7 (1) ◽  
pp. 504-511 ◽  
Author(s):  
J Hindley ◽  
G Phear ◽  
M Stein ◽  
D Beach
Keyword(s):  
Cell Division ◽  
Schizosaccharomyces Pombe ◽  
Cell Cycle Control ◽  
Temperature Sensitive ◽  
Base Pairs ◽  
Direct Role ◽  
Protein Coding ◽  
Dna Fragment ◽  
Rna Transcript ◽  
Translational Product

Sucl+ was originally identified as a DNA sequence that, at high copy number, rescued Schizosaccharomyces pombe strains carrying certain temperature-sensitive alleles of the cdc2 cell cycle control gene. We determined the nucleotide sequence of a 1,083-base-pair Sucl+ DNA fragment and S1 mapped its 866-nucleotide RNA transcript. The protein-coding sequence of the gene is interrupted by two intervening sequences of 115 and 51 base pairs. The predicted translational product of the gene is a protein of 13 kilodaltons. A chromosomal gene disruption of Sucl+ was constructed in a diploid S. pombe strain. Germinating spores carrying a null allele of the gene were capable of very limited cell division, following which many cells became highly elongated. The Sucl+ gene was also strongly overexpressed under the control of a heterologous S. pombe promoter. Overexpression of Sucl+ is not lethal but causes a division delay such that cells are approximately twice the normal length at division. These data suggest that Sucl+ encodes a protein which plays a direct role in the cell division cycle of S. pombe.

The Schizosaccharomyces pombe hus5 gene encodes a ubiquitin conjugating enzyme required for normal mitosis

1995 ◽  
Vol 108 (2) ◽  
pp. 475-486 ◽  
Author(s):  
F. al-Khodairy ◽  
T. Enoch ◽  
I.M. Hagan ◽  
A.M. Carr
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Schizosaccharomyces Pombe ◽  
Cell Cycle Control ◽  
S Phase ◽  
Temperature Sensitive ◽  
Checkpoint Control ◽  
Ubiquitin Conjugating Enzyme ◽  
Efficient Recovery ◽  
Mediate Cell

Normal eukaryotic cells do not enter mitosis unless DNA is fully replicated and repaired. Controls called ‘checkpoints’, mediate cell cycle arrest in response to unreplicated or damaged DNA. Two independent Schizosaccharomyces pombe mutant screens, both of which aimed to isolate new elements involved in checkpoint controls, have identified alleles of the hus5+ gene that are abnormally sensitive to both inhibitors of DNA synthesis and to ionizing radiation. We have cloned and sequenced the hus5+ gene. It is a novel member of the E2 family of ubiquitin conjugating enzymes (UBCs). To understand the role of hus5+ in cell cycle control we have characterized the phenotypes of the hus5 mutants and the hus5 gene disruption. We find that, whilst the mutants are sensitive to inhibitors of DNA synthesis and to irradiation, this is not due to an inability to undergo mitotic arrest. Thus, the hus5+ gene product is not directly involved in checkpoint control. However, in common with a large class of previously characterized checkpoint genes, it is required for efficient recovery from DNA damage or S-phase arrest and manifests a rapid death phenotype in combination with a temperature sensitive S phase and late S/G2 phase cdc mutants. In addition, hus5 deletion mutants are severely impaired in growth and exhibit high levels of abortive mitoses, suggesting a role for hus5+ in chromosome segregation. We conclude that this novel UBC enzyme plays multiple roles and is virtually essential for cell proliferation.

Site-specific mutagenesis of cdc2+, a cell cycle control gene of the fission yeast Schizosaccharomyces pombe

1986 ◽  
Vol 6 (10) ◽  
pp. 3523-3530
Author(s):  
R Booher ◽  
D Beach
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Cell Cycle Control ◽  
Temperature Sensitive ◽  
Protein Kinase Activity ◽  
Atp Binding Site ◽  
Leu2 Gene ◽  
Cdc2 Gene ◽  
A Site

The cdc2+ gene of Schizosaccharomyces pombe is homologous to the CDC28 gene of Saccharomyces cerevisiae. Both genes share limited homology with vertebrate protein kinases and have protein kinase activity. cdc2+ has been subjected to mutagenesis in vitro. A null allele of the gene, constructed by insertion of the S. cerevisiae LEU2 gene into a site within the gene, has a phenotype similar to that of many temperature-sensitive alleles of cdc2. Mutations within the predicted ATP-binding site and in a region which may be a site of phosphorylation result in loss of cdc2+ activity. A single substitution of Gly-146 to Asp-146 has been identified in cdc2-1w, a dominant activated allele of the gene. The four introns within the cdc2+ gene have been deleted. The resulting gene not only functions in fission yeast but also rescues cdc28(Ts) strains of S. cerevisiae, a property which is not shared by the genomic cdc2+ gene.

scholarly journals Cell cycle arrest of cdc mutants and specificity of the RAD9 checkpoint.

Genetics ◽  
1993 ◽  
Vol 134 (1) ◽  
pp. 63-80 ◽  
Author(s):  
T A Weinert ◽  
L H Hartwell
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Dna Replication ◽  
Cell Cycle Control ◽  
Dna Lesions ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
A Cell ◽  
G2 Phase ◽  
Rad Mutants

Abstract In eucaryotes a cell cycle control called a checkpoint ensures that mitosis occurs only after chromosomes are completely replicated and any damage is repaired. The function of this checkpoint in budding yeast requires the RAD9 gene. Here we examine the role of the RAD9 gene in the arrest of the 12 cell division cycle (cdc) mutants, temperature-sensitive lethal mutants that arrest in specific phases of the cell cycle at a restrictive temperature. We found that in four cdc mutants the cdc rad9 cells failed to arrest after a shift to the restrictive temperature, rather they continued cell division and died rapidly, whereas the cdc RAD cells arrested and remained viable. The cell cycle and genetic phenotypes of the 12 cdc RAD mutants indicate the function of the RAD9 checkpoint is phase-specific and signal-specific. First, the four cdc RAD mutants that required RAD9 each arrested in the late S/G2 phase after a shift to the restrictive temperature when DNA replication was complete or nearly complete, and second, each leaves DNA lesions when the CDC gene product is limiting for cell division. Three of the four CDC genes are known to encode DNA replication enzymes. We found that the RAD17 gene is also essential for the function of the RAD9 checkpoint because it is required for phase-specific arrest of the same four cdc mutants. We also show that both X- or UV-irradiated cells require the RAD9 and RAD17 genes for delay in the G2 phase. Together, these results indicate that the RAD9 checkpoint is apparently activated only by DNA lesions and arrests cell division only in the late S/G2 phase.

scholarly journals Schizosaccharomyces pombe Noc3 Is Essential for Ribosome Biogenesis and Cell Division but Not DNA Replication

2008 ◽  
Vol 7 (9) ◽  
pp. 1433-1440 ◽  
Author(s):  
Christopher R. Houchens ◽  
Audrey Perreault ◽  
François Bachand ◽  
Thomas J. Kelly
Keyword(s):  
Cell Division ◽  
Dna Replication ◽  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Ribosome Biogenesis ◽  
Budding Yeast ◽  
Ribosomal Subunit ◽  
Dna Helicase ◽  
Yeast Cells ◽  
Direct Role

ABSTRACT The initiation of eukaryotic DNA replication is preceded by the assembly of prereplication complexes (pre-RCs) at chromosomal origins of DNA replication. Pre-RC assembly requires the essential DNA replication proteins ORC, Cdc6, and Cdt1 to load the MCM DNA helicase onto chromatin. Saccharomyces cerevisiae Noc3 (ScNoc3), an evolutionarily conserved protein originally implicated in 60S ribosomal subunit trafficking, has been proposed to be an essential regulator of DNA replication that plays a direct role during pre-RC formation in budding yeast. We have cloned Schizosaccharomyces pombe noc3 + (Spnoc3 +), the S. pombe homolog of the budding yeast ScNOC3 gene, and functionally characterized the requirement for the SpNoc3 protein during ribosome biogenesis, cell cycle progression, and DNA replication in fission yeast. We showed that fission yeast SpNoc3 is a functional homolog of budding yeast ScNoc3 that is essential for cell viability and ribosome biogenesis. We also showed that SpNoc3 is required for the normal completion of cell division in fission yeast. However, in contrast to the proposal that ScNoc3 plays an essential role during DNA replication in budding yeast, we demonstrated that fission yeast cells do enter and complete S phase in the absence of SpNoc3, suggesting that SpNoc3 is not essential for DNA replication in fission yeast.

scholarly journals Mcs4, a Two-Component System Response Regulator Homologue, Regulates the Schizosaccharomyces pombe Cell Cycle Control

Genetics ◽  
1997 ◽  
Vol 147 (3) ◽  
pp. 1043-1051 ◽  
Author(s):  
Guillaume Cottarel
Keyword(s):  
Cell Cycle ◽  
Schizosaccharomyces Pombe ◽  
Response Regulator ◽  
Cell Cycle Control ◽  
Mitotic Catastrophe ◽  
System Response ◽  
Temperature Sensitive ◽  
Two Component System ◽  
Component System ◽  
Two Component

The Schizosaccharomyces pombe cdc2-3w weel-50 double mutant displays a temperature-sensitive lethal phenotype termed mitotic catastrophe. Six mitotic catastrophe suppressor (mcs1-6) genes were identified in a genetic screen designed to identify regulators of cdc2. Mutations in mcs1-6 suppress the cdc2-3w weel-50 temperature-sensitive growth defect. Here, the cloning of mcs4 is described. The mcs4 gene product displays significant sequence homology to members of the two-component system response regulator protein family. Strains carrying the mcs4 and cdc25 mutations display a synthetic osmotic lethal phenotype along with an inability to grow on minimal synthetic medium. These phenotypes are suppressed by a mutation in wee1. In addition, the wis1 gene, encoding a stress-activated mitogen-activated protein kinase kinase, was identified as a dosage suppressor in this screen. These findings link the two-component signal transduction system to stress response and cell cycle control in S. pombe.

scholarly journals Site-specific mutagenesis of cdc2+, a cell cycle control gene of the fission yeast Schizosaccharomyces pombe.

1986 ◽  
Vol 6 (10) ◽  
pp. 3523-3530 ◽  
Author(s):  
R Booher ◽  
D Beach
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Fission Yeast ◽  
Cell Cycle Control ◽  
Temperature Sensitive ◽  
Protein Kinase Activity ◽  
Atp Binding Site ◽  
Leu2 Gene ◽  
Cdc2 Gene ◽  
A Site

The cdc2+ gene of Schizosaccharomyces pombe is homologous to the CDC28 gene of Saccharomyces cerevisiae. Both genes share limited homology with vertebrate protein kinases and have protein kinase activity. cdc2+ has been subjected to mutagenesis in vitro. A null allele of the gene, constructed by insertion of the S. cerevisiae LEU2 gene into a site within the gene, has a phenotype similar to that of many temperature-sensitive alleles of cdc2. Mutations within the predicted ATP-binding site and in a region which may be a site of phosphorylation result in loss of cdc2+ activity. A single substitution of Gly-146 to Asp-146 has been identified in cdc2-1w, a dominant activated allele of the gene. The four introns within the cdc2+ gene have been deleted. The resulting gene not only functions in fission yeast but also rescues cdc28(Ts) strains of S. cerevisiae, a property which is not shared by the genomic cdc2+ gene.

scholarly journals Genetic Analyses of Schizosaccharomyces pombe dna2+ Reveal That Dna2 Plays an Essential Role in Okazaki Fragment Metabolism

Genetics ◽  
2000 ◽  
Vol 155 (3) ◽  
pp. 1055-1067
Author(s):  
Ho-Young Kang ◽  
Eunjoo Choi ◽  
Sung-Ho Bae ◽  
Kyoung-Hwa Lee ◽  
Byung-Soo Gim ◽  
...  
Keyword(s):  
Schizosaccharomyces Pombe ◽  
S Phase ◽  
Dna Ligase ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Direct Role ◽  
Okazaki Fragment ◽  
Dna Ligase I ◽  
Genes Encoding

Abstract In this report, we investigated the phenotypes caused by temperature-sensitive (ts) mutant alleles of dna2+ of Schizosaccharomyces pombe, a homologue of DNA2 of budding yeast, in an attempt to further define its function in vivo with respect to lagging-strand synthesis during the S-phase of the cell cycle. At the restrictive temperature, dna2 (ts) cells arrested at late S-phase but were unaffected in bulk DNA synthesis. Moreover, they exhibited aberrant mitosis when combined with checkpoint mutations, in keeping with a role for Dna2 in Okazaki fragment maturation. Similarly, spores in which dna2+ was disrupted duplicated their DNA content during germination and also arrested at late S-phase. Inactivation of dna2+ led to chromosome fragmentation strikingly similar to that seen when cdc17+, the DNA ligase I gene, is inactivated. The temperature-dependent lethality of dna2 (ts) mutants was suppressed by overexpression of genes encoding subunits of polymerase δ (cdc1+ and cdc27+), DNA ligase I (cdc17+), and Fen-1 (rad2+). Each of these gene products plays a role in the elongation or maturation of Okazaki fragments. Moreover, they all interacted with S. pombe Dna2 in a yeast two-hybrid assay, albeit to different extents. On the basis of these results, we conclude that dna2+ plays a direct role in the Okazaki fragment elongation and maturation. We propose that dna2+ acts as a central protein to form a complex with other proteins required to coordinate the multienzyme process for Okazaki fragment elongation and maturation.

scholarly journals Rho3p Regulates Cell Separation by Modulating Exocyst Function in Schizosaccharomyces pombe

Genetics ◽  
2003 ◽  
Vol 164 (4) ◽  
pp. 1323-1331
Author(s):  
Hongyan Wang ◽  
Xie Tang ◽  
Mohan K Balasubramanian
Keyword(s):  
Cell Division ◽  
Schizosaccharomyces Pombe ◽  
Cell Separation ◽  
Model Organism ◽  
Temperature Sensitive ◽  
Complex Cells ◽  
Exocyst Complex ◽  
Primary Septum ◽  
Rho Family ◽  
Growth Phenotype

Abstract Cytokinesis is the final stage of the cell division cycle in which the mother cell is physically divided into two daughters. In recent years the fission yeast Schizosaccharomyces pombe has emerged as an attractive model organism for the study of cytokinesis, since it divides using an actomyosin ring whose constriction is coordinated with the centripetal deposition of new membranes and a division septum. The final step of cytokinesis in S. pombe requires the digestion of the primary septum to liberate two daughters. We have previously shown that the multiprotein exocyst complex is essential for this process. Here we report the isolation of rho3+, encoding a Rho family GTPase, as a high-copy suppressor of an exocyst mutant, sec8-1. Overproduction of Rho3p also suppressed the temperature-sensitive growth phenotype observed in cells lacking Exo70p, another conserved component of the S. pombe exocyst complex. Cells deleted for rho3 arrest at higher growth temperatures with two or more nuclei and uncleaved division septa between pairs of nuclei. rho3Δ cells accumulate ∼100-nm vesicle-like structures. These phenotypes are all similar to those observed in exocyst component mutants, consistent with a role for Rho3p in modulation of exocyst function. Taken together, our results suggest the possibility that S. pombe Rho3p regulates cell separation by modulation of exocyst function.

scholarly journals Pseudoreversion analysis indicates a direct role of cell division genes in polar morphogenesis and differentiation in Caulobacter crescentus.

Genetics ◽  
1991 ◽  
Vol 129 (3) ◽  
pp. 623-630 ◽  
Author(s):  
J M Sommer ◽  
A Newton
Keyword(s):  
Cell Division ◽  
Caulobacter Crescentus ◽  
Temperature Sensitive ◽  
Sensitive Cell ◽  
Direct Role ◽  
Pleiotropic Gene ◽  
Cold Sensitive ◽  
Extragenic Suppressors ◽  
Pleiotropic Mutation

Abstract A pseudoreversion analysis was used to examine the role of cell division genes in polar morphogenesis in Caulobacter crescentus. Extragenic suppressors of temperature sensitive mutations in pleC, a pleiotropic gene required for cell motility, formation of polar phi CbK bacteriophage receptors, and stalk formation, were isolated. These suppressors, which restored motility at 37 degrees C, simultaneously conferred a cold sensitive cell division phenotype and they were mapped to the three new cell division genes divJ, divL and divK. The cold-sensitive mutations in divL, and to a lesser extent divJ, exhibited a relatively narrow range of suppression. The cold-sensitive cell division mutation in divK, by contrast, suppressed all pleC mutations examined and behaved as a classical bypass suppressor. The direct role of this cell division gene in the regulation of motility is suggested by the observation that divK341 mapped to the same locus as pleD301, a pleiotropic mutation that prevents loss of motility and stalk formation. These results provide strong evidence that the cell division and developmental pathways are interconnected and they support our earlier conclusion that cell division is required for the regulation of polar morphogenesis and differentiation in C. crescentus.

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