scholarly journals Control of DNA replication licensing in a cell cycle

2002 ◽  
Vol 7 (6) ◽  
pp. 523-534 ◽  
Author(s):  
Hideo Nishitani ◽  
Zoi Lygerou
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
A Cell

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 Evidence for a dual role for TC4 protein in regulating nuclear structure and cell cycle progression.

1994 ◽  
Vol 125 (4) ◽  
pp. 705-719 ◽  
Author(s):  
S Kornbluth ◽  
M Dasso ◽  
J Newport
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Nuclear Structure ◽  
Cell Cycle Progression ◽  
Cycle Progression ◽  
Nuclear Assembly ◽  
Egg Extracts ◽  
A Cell ◽  
Xenopus Egg Extracts

TC4, a ras-like G protein, has been implicated in the feedback pathway linking the onset of mitosis to the completion of DNA replication. In this report we find distinct roles for TC4 in both nuclear assembly and cell cycle progression. Mutant and wild-type forms of TC4 were added to Xenopus egg extracts capable of assembling nuclei around chromatin templates in vitro. We found that a mutant TC4 protein defective in GTP binding (GDP-bound form) suppressed nuclear growth and prevented DNA replication. Nuclear transport under these conditions approximated normal levels. In a separate set of experiments using a cell-free extract of Xenopus eggs that cycles between S and M phases, the GDP-bound form of TC4 had dramatic effects, blocking entry into mitosis even in the complete absence of nuclei. The effect of this mutant TC4 protein on cell cycle progression is mediated by phosphorylation of p34cdc2 on tyrosine and threonine residues, negatively regulating cdc2 kinase activity. Therefore, we provide direct biochemical evidence for a role of TC4 in both maintaining nuclear structure and in the signaling pathways that regulate entry into mitosis.

The Effect of Cell Mass on the Cell Cycle Timing and Duration of S-Phase in Fission Yeast

1979 ◽  
Vol 39 (1) ◽  
pp. 215-233
Author(s):  
KIM NASMYTH ◽  
PAUL NURSE ◽  
R. S. S. FRASER
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Fission Yeast ◽  
Critical Level ◽  
Single Cells ◽  
Cell Mass ◽  
S Phase ◽  
Pulse Labelling ◽  
Random Transition ◽  
A Cell

Request for reprints to Paul Nurse. Two isotopic methods for measuring DNA replication in the fission yeast Schizosaccharomyces pombe are described. The first is a method for measuring the total quantity of [3H]uracil incorporated into DNA after pulse labelling. The second is a means of detecting DNA replication in single cells by autoradiography. Both of these techniques have been used to investigate the timing and duration of S-phase in a series of mutant strains whose cell mass at division varies over a 3-fold range. The results support the hypothesis that in S. pombe there are 2 different controls over the timing of S-phase: an attainment of a critical cell mass and a dependency upon the completion of the previous mitosis coupled with a short minimum time in G1. Strains whose cell mass at birth is above this critical level initiate DNA replication almost immediately after septation, that is, very soon after the previous mitosis. Strains whose cell mass at birth is below the critical level do not initiate replication until the critical cell mass is attained. The duration of S-phase has been estimated from the proportion of cells whose nuclei are labelled after a pulse of given duration. S-phase is short in S. pombe, lasting only about 0.1 of a cell cycle in wild type. Cell mass at S-phase does not have any consistent effect on this length. We have also investigated the degree of synchrony of S-phase initiation in daughter cells, and have found that, in a cell cycle 240 min long, their S-phases are initiated within 1–2 min of each other. This result indicates that between sisters variability in the duration of the G1 phase is small compared with variability in the total cell cycle time, and argues against the hypothesis that the rate of cell cycle traverse is determined by a random transition in G1.

scholarly journals Dynamics of pre-replication complex proteins during the cell division cycle

2004 ◽  
Vol 359 (1441) ◽  
pp. 7-16 ◽  
Author(s):  
Supriya G. Prasanth ◽  
Juan Méndez ◽  
Kannanganattu V. Prasanth ◽  
Bruce Stillman
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Dna Replication ◽  
Origin Recognition Complex ◽  
Cell Division Cycle ◽  
Vital Functions ◽  
A Cell ◽  
Bona Fide ◽  
Mcm Proteins ◽  
Key Participants

Replication of the human genome every time a cell divides is a highly coordinated process that ensures accurate and efficient inheritance of the genetic information. The molecular mechanism that guarantees that many origins of replication fire only once per cell–cycle has been the area of intense research. The origin recognition complex (ORC) marks the position of replication origins in the genome and serves as the landing pad for the assembly of a multiprotein, pre–replicative complex (pre–RC) at the origins, consisting of ORC, cell division cycle 6 (Cdc6), Cdc10–dependent transcript (Cdt1) and mini–chromosome maintenance (MCM) proteins. The MCM proteins serve as key participants in the mechanism that limits eukaryotic DNA replication to once–per–cell–cycle and its binding to the chromatin marks the final step of pre–RC formation, a process referred to as ‘replication licensing’. We present data demonstrating how the MCM proteins associate with the chromatin during the G1 phase, probably defining pre–RCs and then anticipate replication fork movement in a precisely coordinated manner during the S phase of the cell cycle. The process of DNA replication must also be carefully coordinated with other cell–cycle processes including mitosis and cytokinesis. Some of the proteins that control initiation of DNA replication are likely to interact with the pathways that control these important cell–cycle transitions. Herein, we discuss the participation of human ORC proteins in other vital functions, in addition to their bona fide roles in replication.

The Spd1p S phase inhibitor can activate the DNA replication checkpoint pathway in fission yeast

2000 ◽  
Vol 113 (23) ◽  
pp. 4341-4350 ◽  
Author(s):  
A. Borgne ◽  
P. Nurse
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Cell Cycle Progression ◽  
S Phase ◽  
Checkpoint Control ◽  
Replication Checkpoint ◽  
Checkpoint Pathway ◽  
Dna Replication Checkpoint ◽  
A Cell ◽  
Checkpoint Genes

Spd1p (for S phase delayed) is a cell cycle inhibitor in Schizosaccharomyces pombe. Spd1p overexpression blocks the onset of both S phase and mitosis. In this study, we have investigated the mechanisms by which Spd1p overexpression blocks cell cycle progression, focussing on the block over mitotic onset. High levels of Spd1p lead to an increase in Y15 phosphorylation of Cdc2p and we show that the block over G(2) requires the Wee1p kinase and is dependent on the rad and chk1/cds1 checkpoint genes. We propose that high levels of Spd1p in G(2) cells activate the DNA replication checkpoint control, which leads to a Wee1p-dependent increase of Cdc2p Y15 phosphorylation blocking onset of mitosis. The Spd1p block at S phase onset may act by interfering directly with DNA replication, and also activates the G(2)rad/hus checkpoint pathway to block mitosis.

Fission yeast Nda1 and Nda4, MCM homologs required for DNA replication, are constitutive nuclear proteins

1996 ◽  
Vol 109 (2) ◽  
pp. 319-326 ◽  
Author(s):  
N. Okishio ◽  
Y. Adachi ◽  
M. Yanagida
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Fission Yeast ◽  
Budding Yeast ◽  
Affinity Column ◽  
Wild Type ◽  
M Phase ◽  
A Cell ◽  
Mcm Proteins ◽  
Cycle Dependent

The nda1+ and nda4+ genes of the fission yeast Schizosaccharomyces pombe encode proteins similar to budding yeast MCM2 and MCM5/CDC46, respectively, which are required for the early stages of DNA replication. The budding yeast Mcm proteins display cell-cycle dependent localization. They are present in the nucleus specifically from late M phase until the beginning of S phase, so that they were suggested to be components of a replication licensing factor, a positive factor for the onset of replication, which is thought to be inactivated after use, thus restricting replication to only once in a cell cycle. In the present study, we raised antibodies against Nda1 or Nda4 and identified 115 kDa and 80 kDa proteins, respectively. Their immunolocalization was examined in wild-type cells and in various cell-cycle mutants. Both Nda1 and Nda4 proteins remained primarily in the nucleus throughout the cell cycle. In mutants arrested in G1, S, and G2 phases, these proteins were also enriched in the nucleus. These results indicate that the dramatic change in subcellular localization as seen in budding yeast is not essential in fission yeast for the functions of Nda1 and Nda4 proteins to be executed. The histidine-tagged nda1+ gene was constructed and integrated into the chromosome to replace the wild-type nda1+ gene. The resulting His-tagged Nda1 protein was adsorbed to the Ni-affinity column, and co-eluted with the untagged Nda4 protein, suggesting that they formed a complex.

scholarly journals Topoisomerase IIα prevents ultrafine anaphase bridges by two mechanisms

Open Biology ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 190259
Author(s):  
Simon Gemble ◽  
Géraldine Buhagiar-Labarchède ◽  
Rosine Onclercq-Delic ◽  
Gaëlle Fontaine ◽  
Sarah Lambert ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Dna Replication ◽  
Free Resolution ◽  
Cycle Phase ◽  
Dependent Manner ◽  
Topoisomerase Iiα ◽  
Anaphase Bridges ◽  
A Cell ◽  
Cycle Dependent

Topoisomerase IIα (Topo IIα), a well-conserved double-stranded DNA (dsDNA)-specific decatenase, processes dsDNA catenanes resulting from DNA replication during mitosis. Topo IIα defects lead to an accumulation of ultrafine anaphase bridges (UFBs), a type of chromosome non-disjunction. Topo IIα has been reported to resolve DNA anaphase threads, possibly accounting for the increase in UFB frequency upon Topo IIα inhibition. We hypothesized that the excess UFBs might also result, at least in part, from an impairment of the prevention of UFB formation by Topo IIα. We found that Topo IIα inhibition promotes UFB formation without affecting the global disappearance of UFBs during mitosis, but leads to an aberrant UFB resolution generating DNA damage within the next G1. Moreover, we demonstrated that Topo IIα inhibition promotes the formation of two types of UFBs depending on cell cycle phase. Topo IIα inhibition during S-phase compromises complete DNA replication, leading to the formation of UFB-containing unreplicated DNA, whereas Topo IIα inhibition during mitosis impedes DNA decatenation at metaphase–anaphase transition, leading to the formation of UFB-containing DNA catenanes. Thus, Topo IIα activity is essential to prevent UFB formation in a cell-cycle-dependent manner and to promote DNA damage-free resolution of UFBs.

scholarly journals Tetrapyrrole signal as a cell-cycle coordinator from organelle to nuclear DNA replication in plant cells

2009 ◽  
Vol 106 (3) ◽  
pp. 803-807 ◽  
Author(s):  
Yuki Kobayashi ◽  
Yu Kanesaki ◽  
Ayumi Tanaka ◽  
Haruko Kuroiwa ◽  
Tsuneyoshi Kuroiwa ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Nuclear Dna ◽  
Plant Cells ◽  
A Cell

scholarly journals Negative control of bacterial DNA replication by a cell cycle regulatory protein that binds at the chromosome origin

1998 ◽  
Vol 95 (1) ◽  
pp. 120-125 ◽  
Author(s):  
K. C. Quon ◽  
B. Yang ◽  
I. J. Domian ◽  
L. Shapiro ◽  
G. T. Marczynski
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Regulatory Protein ◽  
Negative Control ◽  
Bacterial Dna ◽  
Cell Cycle Regulatory Protein ◽  
A Cell ◽  
Bacterial Dna Replication
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