The Caenorhabditis elegans gene ncc-1 encodes a cdc2-related kinase required for M phase in meiotic and mitotic cell divisions, but not for S phase

We have identified six protein kinases that belong to the family of cdc2-related kinases in Caenorhabditis elegans. Results from RNA interference experiments indicate that at least one of these kinases is required for cell-cycle progression during meiosis and mitosis. This kinase, encoded by the ncc-1 gene, is closely related to human Cdk1/Cdc2, Cdk2 and Cdk3 and yeast CDC28/cdc2(+). We addressed whether ncc-1 acts to promote passage through a single transition or multiple transitions in the cell cycle, analogous to Cdks in vertebrates or yeasts, respectively. We isolated five recessive ncc-1 mutations in a genetic screen for mutants that resemble larval arrested ncc-1(RNAi) animals. Our results indicate that maternal ncc-1 product is sufficient for embryogenesis, and that zygotic expression is required for cell divisions during larval development. Cells that form the postembryonic lineages in wild-type animals do not enter mitosis in ncc-1 mutants, as indicated by lack of chromosome condensation and nuclear envelope breakdown. However, progression through G1 and S phase appears unaffected, as revealed by expression of ribonucleotide reductase, incorporation of BrdU and DNA quantitation. Our results indicate that C. elegans uses multiple Cdks to regulate cell-cycle transitions and that ncc-1 is the C. elegans ortholog of Cdk1/Cdc2 in other metazoans, required for M phase in meiotic as well as mitotic cell cycles.

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The Paramyxovirus Simian Virus 5 V Protein Slows Progression of the Cell Cycle

Journal of Virology ◽

10.1128/jvi.74.19.9152-9166.2000 ◽

2000 ◽

Vol 74 (19) ◽

pp. 9152-9166 ◽

Cited By ~ 89

Author(s):

Grace Y. Lin ◽

Robert A. Lamb

Keyword(s):

Cell Cycle ◽

Cell Cycle Progression ◽

Simian Virus ◽

S Phase ◽

V Protein ◽

Simian Virus 5 ◽

C Terminus ◽

M Phase ◽

Infected Cells ◽

Affect Cell Cycle Progression

ABSTRACT Infection of cells by many viruses affects the cell division cycle of the host cell to favor viral replication. We examined the ability of the paramyxovirus simian parainfluenza virus 5 (SV5) to affect cell cycle progression, and we found that SV5 slows the rate of proliferation of HeLa T4 cells. The SV5-infected cells had a delayed transition from G1 to S phase and prolonged progression through S phase, and some of the infected cells were arrested in G2 or M phase. The levels of p53 and p21CIP1were not increased in SV5-infected cells compared to mock-infected cells, suggesting that the changes in the cell cycle occur through a p53-independent mechanism. However, the phosphorylation of the retinoblastoma protein (pRB) was delayed and prolonged in SV5-infected cells. The changes in the cell cycle were also observed in cells expressing the SV5 V protein but not in the cells expressing the SV5 P protein or the V protein lacking its unique C terminus (VΔC). The unique C terminus of the V protein of SV5 was shown previously to interact with DDB1, which is the 127-kDa subunit of the multifunctional damage-specific DNA-binding protein (DDB) heterodimer. The coexpression of DDB1 with V can partially restore the changes in the cell cycle caused by expression of the V protein.

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Coupling Phosphate Homeostasis to Cell Cycle-Specific Transcription: Mitotic Activation of Saccharomyces cerevisiae PHO5 by Mcm1 and Forkhead Proteins

Molecular and Cellular Biology ◽

10.1128/mcb.00222-09 ◽

2009 ◽

Vol 29 (18) ◽

pp. 4891-4905 ◽

Cited By ~ 16

Author(s):

Santhi Pondugula ◽

Daniel W. Neef ◽

Warren P. Voth ◽

Russell P. Darst ◽

Archana Dhasarathy ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Cycle ◽

Cell Cycle Progression ◽

Mitotic Cell ◽

Dependent Manner ◽

Phosphate Homeostasis ◽

Periodic Cell ◽

M Phase ◽

Cycle Dependent ◽

Nutrient Homeostasis

ABSTRACT Cells devote considerable resources to nutrient homeostasis, involving nutrient surveillance, acquisition, and storage at physiologically relevant concentrations. Many Saccharomyces cerevisiae transcripts coding for proteins with nutrient uptake functions exhibit peak periodic accumulation during M phase, indicating that an important aspect of nutrient homeostasis involves transcriptional regulation. Inorganic phosphate is a central macronutrient that we have previously shown oscillates inversely with mitotic activation of PHO5. The mechanism of this periodic cell cycle expression remains unknown. To date, only two sequence-specific activators, Pho4 and Pho2, were known to induce PHO5 transcription. We provide here evidence that Mcm1, a MADS-box protein, is essential for PHO5 mitotic activation. In addition, we found that cells simultaneously lacking the forkhead proteins, Fkh1 and Fkh2, exhibited a 2.5-fold decrease in PHO5 expression. The Mcm1-Fkh2 complex, first shown to transactivate genes within the CLB2 cluster that drive G2/M progression, also associated directly at the PHO5 promoter in a cell cycle-dependent manner in chromatin immunoprecipitation assays. Sds3, a component specific to the Rpd3L histone deacetylase complex, was also recruited to PHO5 in G1. These findings provide (i) further mechanistic insight into PHO5 mitotic activation, (ii) demonstrate that Mcm1-Fkh2 can function combinatorially with other activators to yield late M/G1 induction, and (iii) couple the mitotic cell cycle progression machinery to cellular phosphate homeostasis.

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Three genes of the MAP kinase cascade, mek-2, mpk-1/sur-1 and let-60 ras, are required for meiotic cell cycle progression in Caenorhabditis elegans

Development ◽

10.1242/dev.121.8.2525 ◽

1995 ◽

Vol 121 (8) ◽

pp. 2525-2535 ◽

Cited By ~ 34

Author(s):

D.L. Church ◽

K.L. Guan ◽

E.J. Lambie

Keyword(s):

Cell Cycle ◽

Caenorhabditis Elegans ◽

Map Kinase ◽

Germ Cells ◽

Cell Cycle Progression ◽

Extended Period ◽

Meiotic Cell ◽

Cycle Progression ◽

C Elegans ◽

Genetic Mosaic

In the germline of Caenorhabditis elegans hermaphrodites, meiotic cell cycle progression occurs in spatially restricted regions. Immediately after leaving the distal mitotic region, germ cells enter meiosis and thereafter remain in the pachytene stage of first meiotic prophase for an extended period. At the dorsoventral gonadal flexure, germ cells exit pachytene and subsequently become arrested in diakinesis. We have found that exit from pachytene is dependent on the function of three members of the MAP kinase signaling cascade. One of these genes, mek-2, is a newly identified C. elegans MEK (MAP kinase kinase). The other two genes, mpk-1/sur-1 (MAP kinase) and let-60 ras, were previously identified based on their roles in vulval induction and are shown here to act in combination with mek-2 to permit exit from pachytene. Through genetic mosaic analysis, we demonstrate that the expression of mpk-1/sur-1 is required within the germline to permit exit from pachytene.

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Control of cell cycle progression by phosphorylation of cyclin-dependent kinase (CDK) substrates

Bioscience Reports ◽

10.1042/bsr20090171 ◽

2010 ◽

Vol 30 (4) ◽

pp. 243-255 ◽

Cited By ~ 65

Author(s):

Randy Suryadinata ◽

Martin Sadowski ◽

Boris Sarcevic

Keyword(s):

Cell Cycle ◽

Cell Division ◽

Cell Cycle Progression ◽

Genetic Material ◽

Eukaryotic Cell ◽

S Phase ◽

Cycle Progression ◽

M Phase ◽

Unicellular Organisms ◽

Multicellular Organisms

The eukaryotic cell cycle is a fundamental evolutionarily conserved process that regulates cell division from simple unicellular organisms, such as yeast, through to higher multicellular organisms, such as humans. The cell cycle comprises several phases, including the S-phase (DNA synthesis phase) and M-phase (mitotic phase). During S-phase, the genetic material is replicated, and is then segregated into two identical daughter cells following mitotic M-phase and cytokinesis. The S- and M-phases are separated by two gap phases (G1 and G2) that govern the readiness of cells to enter S- or M-phase. Genetic and biochemical studies demonstrate that cell division in eukaryotes is mediated by CDKs (cyclin-dependent kinases). Active CDKs comprise a protein kinase subunit whose catalytic activity is dependent on association with a regulatory cyclin subunit. Cell-cycle-stage-dependent accumulation and proteolytic degradation of different cyclin subunits regulates their association with CDKs to control different stages of cell division. CDKs promote cell cycle progression by phosphorylating critical downstream substrates to alter their activity. Here, we will review some of the well-characterized CDK substrates to provide mechanistic insights into how these kinases control different stages of cell division.

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The distribution pattern of proliferating cell nuclear antigen in the nuclei of Leishmania donovani

Microbiology ◽

10.1099/mic.0.033217-0 ◽

2009 ◽

Vol 155 (11) ◽

pp. 3748-3757 ◽

Cited By ~ 21

Author(s):

Devanand Kumar ◽

Neha Minocha ◽

Kalpana Rajanala ◽

Swati Saha

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Proliferating Cell Nuclear Antigen ◽

Cell Cycle Progression ◽

Leishmania Donovani ◽

Systemic Disease ◽

S Phase ◽

Nuclear Antigen ◽

M Phase ◽

Proliferating Cell

DNA replication in eukaryotes is a highly conserved process marked by the licensing of multiple origins, with pre-replication complex assembly in G1 phase, followed by the onset of replication at these origins in S phase. The two strands replicate by different mechanisms, and DNA synthesis is brought about by the activity of the replicative DNA polymerases Pol δ and Pol ϵ. Proliferating cell nuclear antigen (PCNA) augments the processivity of these polymerases by serving as a DNA sliding clamp protein. This study reports the cloning of PCNA from the protozoan Leishmania donovani, which is the causative agent of the systemic disease visceral leishmaniasis. PCNA was demonstrated to be robustly expressed in actively proliferating L. donovani promastigotes. We found that the protein was present primarily in the nucleus throughout the cell cycle, and it was found in both proliferating procyclic and metacyclic promastigotes. However, levels of expression of PCNA varied through cell cycle progression, with maximum expression evident in G1 and S phases. The subnuclear pattern of expression of PCNA differed in different stages of the cell cycle; it formed distinct subnuclear foci in S phase, while it was distributed in a more diffuse pattern in G2/M phase and post-mitotic phase cells. These subnuclear foci are the sites of active DNA replication, suggesting that replication factories exist in Leishmania, as they do in higher eukaryotes, thus opening avenues for investigating other Leishmania proteins that are involved in DNA replication as part of these replication factories.

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SCAPER, a novel cyclin A–interacting protein that regulates cell cycle progression

The Journal of Cell Biology ◽

10.1083/jcb.200701166 ◽

2007 ◽

Vol 178 (4) ◽

pp. 621-633 ◽

Cited By ~ 39

Author(s):

William Y. Tsang ◽

Leyu Wang ◽

Zhihong Chen ◽

Irma Sánchez ◽

Brian David Dynlacht

Keyword(s):

Cell Cycle ◽

Cell Cycle Progression ◽

Regulatory Protein ◽

Ectopic Expression ◽

Cyclin A ◽

Eukaryotic Cell ◽

S Phase ◽

Interacting Protein ◽

M Phase

Cyclin A/Cdk2 plays an important role during S and G2/M phases of the eukaryotic cell cycle, but the mechanisms by which it regulates cell cycle events are not fully understood. We have biochemically purified and identified SCAPER, a novel protein that specifically interacts with cyclin A/Cdk2 in vivo. Its expression is cell cycle independent, and it associates with cyclin A/Cdk2 at multiple phases of the cell cycle. SCAPER localizes primarily to the endoplasmic reticulum. Ectopic expression of SCAPER sequesters cyclin A from the nucleus and results specifically in an accumulation of cells in M phase of the cell cycle. RNAi-mediated depletion of SCAPER decreases the cytoplasmic pool of cyclin A and delays the G1/S phase transition upon cell cycle re-entry from quiescence. We propose that SCAPER represents a novel cyclin A/Cdk2 regulatory protein that transiently maintains this kinase in the cytoplasm. SCAPER could play a role in distinguishing S phase– from M phase–specific functions of cyclin A/Cdk2.

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Differential function and expression of Saccharomyces cerevisiae B-type cyclins in mitosis and meiosis

Molecular and Cellular Biology ◽

10.1128/mcb.13.4.2113-2125.1993 ◽

1993 ◽

Vol 13 (4) ◽

pp. 2113-2125

Author(s):

N Grandin ◽

S I Reed

Keyword(s):

Saccharomyces Cerevisiae ◽

Cell Cycle ◽

Kinase Activity ◽

Mitotic Cell ◽

S Phase ◽

Mitotic Cell Cycle ◽

Meiotic Cell ◽

Cell Cycles ◽

M Phase ◽

Mitotic Cyclin

We have studied the patterns of expression of four B-type cyclins (Clbs), Clb1, Clb2, Clb3, and Clb4, and their ability to activate p34cdc28 during the mitotic and meiotic cell cycles of Saccharomyces cerevisiae. During the mitotic cell cycle, Clb3 and Clb4 were expressed and induced a kinase activity in association with p34cdc28 from early S phase up to mitosis. On the other hand, Clb1 and Clb2 were expressed and activated p34cdc28 later in the mitotic cell cycle, starting in late S phase and continuing up to mitosis. The pattern of expression of Clb3 and Clb4 suggests a possible role in the regulation of DNA replication as well as mitosis. Clb1 and Clb2, whose pattern of expression is similar to that of other known Clbs, are likely to have a role predominantly in the regulation of M phase. During the meiotic cell cycle, Clb1, Clb3, and Clb4 were expressed and induced a p34cdc28-associated kinase activity just before the first meiotic division. The fact that Clb3 and Clb4 were not synthesized earlier, in S phase, suggests that these cyclins, which probably have a role in S phase during the mitotic cell cycle, are not implicated in premeiotic S phase. Clb2, the primary mitotic cyclin in S. cerevisiae, was not detectable during meiosis. Sporulation experiments on strains deleted for one, two, or three Clbs indicate, in agreement with the biochemical data, that Clb1 is the primary cyclin for the regulation of meiosis, while Clb2 is not involved at all.

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Bimodal Degradation of MLL Protein by the Cell Cycle SCFSkp2 and APCCdc20 E3 Lilgases Assures Cell Cycle Execution: A Critical Regulatory Circuit Lost in Leukemogenic MLL-Fusions.

Blood ◽

10.1182/blood.v110.11.828.828 ◽

2007 ◽

Vol 110 (11) ◽

pp. 828-828 ◽

Cited By ~ 1

Author(s):

Han Liu ◽

David Chen ◽

Todd Westergard ◽

Shugaku Takeda ◽

Satoru Sasagawa ◽

...

Keyword(s):

Gene Expression ◽

Cell Cycle ◽

Cell Cycle Progression ◽

Hox Genes ◽

S Phase ◽

Polycomb Group ◽

Cell Cycle Gene ◽

E3 Ligases ◽

M Phase ◽

Phase Progression

Abstract The MLL (mixed lineage leukemia) gene encodes a highly conserved 3,969 aa histone H3 K4 methyl transferase, of which chromosome translocations result in poor prognostic infant and therapy-related leukemias. Mysteriously, the pathognomonic MLL leukemia fusions consist of a common amino(N)-terminal ∼1400 aa of MLL fused in frame with more than 60 different partners with no shared characteristics. The most well known genetic function of MLL is to antagonize polycomb group of proteins for proper Hox gene expression. Consequently deregulated Hox genes caused by MLL translocations contribute to the MLL leukemogenesis. Besides Hox genes, it remains largely undetermined whether MLL participates in other biological processes. The 500kD MLL precursor undergoes evolutionarily conserved proteolytic maturation mediated by Taspase1 (Hsieh et al. 2003, MCB, 23, 186–194; Hsieh et al. 2003, Cell, 115, 293–303). Our recent studies on Taspase1 knockout cells established an MLL-E2F axis in orchestrating core cell cycle gene expression including Cyclins and possibly Cdk inhibitors (Takeda et al. 2006, Genes & Development, 20, 2397–2409). As MLL actively participates in the cell cycle regulation, we investigated the regulation of MLL through cell cycle transition. We uncovered a unique biphasic expression of MLL conferred by defined windows of degradation mediated by specialized cell cycle E3 ligases. Specifically, SCFSkp2 and APCCdc20 mark MLL for degradation at S phase and late M phase, respectively. Abolished peak expression of MLL incurs corresponding defects in G1/S transition and M phase progression. Conversely, over-expression of MLL blocks S phase progression. Remarkably, MLL degradation initiates at its N-terminal ∼1400 aa that is retained in all MLL leukemia fusions. We examined prevalent MLL-fusions, including MLL-AF4, MLL-AF9, MLL-ELL and MLL-ELL, and observed their increased resistance to degradation. Furthermore, the same resistance was observed with the leukemogenic MLL-lacZ but not the non-leukemogenic MLL-Myc tag fusion. Thus, non-oscillating expression of MLL-fusions through the cell cycle, resulted from impaired degradation, likely constitutes the universal mechanism underlying all MLL leukemias. Our data conclude an essential post-translational regulation of MLL by the cell cycle ubiquitin/proteasome system (UPS) to assure the temporal necessity of MLL in coordinating cell cycle progression. Future studies aim at providing a comprehensive analysis on the cell cycle consequences associated with MLL-fusions using genetically modified cells derived from mice carrying various MLL-fusion knockin alleles, including MLL-AF4, MLL-AF9, and MLL-CBP.

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NPP-16/Nup50 Function and CDK-1 Inactivation Are Associated with Anoxia-induced Prophase Arrest in Caenorhabditis elegans

Molecular Biology of the Cell ◽

10.1091/mbc.e09-09-0787 ◽

2010 ◽

Vol 21 (5) ◽

pp. 712-724 ◽

Cited By ~ 12

Author(s):

Vinita A. Hajeri ◽

Brent A. Little ◽

Mary L. Ladage ◽

Pamela A. Padilla

Keyword(s):

Caenorhabditis Elegans ◽

Cell Cycle Progression ◽

Nuclear Periphery ◽

Oxygen Deprivation ◽

Wild Type ◽

Cycle Progression ◽

C Elegans ◽

Nuclear Envelope Breakdown ◽

Inactive Form ◽

Essential Nutrient

Oxygen, an essential nutrient, is sensed by a multiple of cellular pathways that facilitate the responses to and survival of oxygen deprivation. The Caenorhabditis elegans embryo exposed to severe oxygen deprivation (anoxia) enters a state of suspended animation in which cell cycle progression reversibly arrests at specific stages. The mechanisms regulating interphase, prophase, or metaphase arrest in response to anoxia are not completely understood. Characteristics of arrested prophase blastomeres and oocytes are the alignment of condensed chromosomes at the nuclear periphery and an arrest of nuclear envelope breakdown. Notably, anoxia-induced prophase arrest is suppressed in mutant embryos lacking nucleoporin NPP-16/NUP50 function, indicating that this nucleoporin plays an important role in prophase arrest in wild-type embryos. Although the inactive form of cyclin-dependent kinase (CDK-1) is detected in wild-type–arrested prophase blastomeres, the inactive state is not detected in the anoxia exposed npp-16 mutant. Furthermore, we found that CDK-1 localizes near chromosomes in anoxia-exposed embryos. These data support the notion that NPP-16 and CDK-1 function to arrest prophase blastomeres in C. elegans embryos. The anoxia-induced shift of cells from an actively dividing state to an arrested state reveals a previously uncharacterized prophase checkpoint in the C. elegans embryo.

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