How Do Drug-Induced Topoisomerase I-DNA Lesions Signal to the Molecular Interaction Network that Regulates Cell Cycle Checkpoints, DNA Replication, and DNA Repair?

2000 ◽  
Vol 33 (2) ◽  
pp. 175-180 ◽  
Author(s):  
Kurt W. Kohn ◽  
Rhong-Guang Shao ◽  
Yves Pommier
Open Biology ◽  
2011 ◽  
Vol 1 (3) ◽  
pp. 110009 ◽  
Author(s):  
Tongli Zhang ◽  
Bernhard Schmierer ◽  
Béla Novák

The start-transition (START) in the G1 phase marks the point in the cell cycle at which a yeast cell initiates a new round of cell division. Once made, this decision is irreversible and the cell is committed to progressing through the entire cell cycle, irrespective of arrest signals such as pheromone. How commitment emerges from the underlying molecular interaction network is poorly understood. Here, we perform a dynamical systems analysis of an established cell cycle model, which has never been analysed from a commitment perspective. We show that the irreversibility of the START transition and subsequent commitment can be consistently explained in terms of the interplay of multiple bistable molecular switches. By applying an existing mathematical model to a novel problem and by expanding the model in a self-consistent manner, we achieve several goals: we bring together a large number of experimental findings into a coherent theoretical framework; we increase the scope and the applicability of the original model; we give a systems level explanation of how the START transition and the cell cycle commitment arise from the dynamical features of the underlying molecular interaction network; and we make clear, experimentally testable predictions.


Zygote ◽  
1997 ◽  
Vol 5 (2) ◽  
pp. 153-175 ◽  
Author(s):  
Richard Ikegami ◽  
Alma K. Rivera-Bennetts ◽  
Deborah L. Brooker ◽  
Thomas D. Yager

SummaryWe address the developmental activation, in the zebrafish embryo, of intrinsic cell-cycle checkpoints which monitor the DNA replication process and progression through the cell cycle. Eukaryotic DNA replication is probably carried out by a multiprotein complex containing numerous enzymes and accessory factors that act in concert to effect processive DNA synthesis (Applegren, N. et al. (1995) J. Cell. Biochem. 59, 91–107). We have exposed early zebrafish embryos to three chemical agents which are predicted to specifically inhibit the DNA polymerase α, topoisomerase I and topoisomerase II components of the DNA replication complex. We present four findings: (1) Before mid-blastula transition (MBT) an inhibition of DNA synthesis does not block cells from attempting to proceed through mitosis, implying the lack of functional checkpoints. (2) After MBT, the embryo displays two distinct modes of intrinsic checkpoint operation. One mode is a rapid and complete stop of cell division, and the other is an ‘adaptive’ response in which the cell cycle continues to operate, perhaps in a ‘repair’ mode, to generate daughter nuclei with few visible defects. (3) The embryo does not display a maximal capability for the ‘adaptive’ response until several hours after MBT, which is consistent with a slow rranscriptional control mechanism for checkpoint activation. (4) The slow activation of checkpoints at MBT provides a window of time during which inhibitors of DNA synthesis will induce cytogenetic lesions without killing the embryo. This could be useful in the design of a deletion-mutagenesis strategy.


2018 ◽  
Vol 20 (1) ◽  
pp. 74 ◽  
Author(s):  
Guido Keijzers ◽  
Daniela Bakula ◽  
Michael Petr ◽  
Nils Madsen ◽  
Amanuel Teklu ◽  
...  

Human exonuclease 1 (EXO1), a 5′→3′ exonuclease, contributes to the regulation of the cell cycle checkpoints, replication fork maintenance, and post replicative DNA repair pathways. These processes are required for the resolution of stalled or blocked DNA replication that can lead to replication stress and potential collapse of the replication fork. Failure to restart the DNA replication process can result in double-strand breaks, cell-cycle arrest, cell death, or cellular transformation. In this review, we summarize the involvement of EXO1 in the replication, DNA repair pathways, cell cycle checkpoints, and the link between EXO1 and cancer.


BioEssays ◽  
1994 ◽  
Vol 16 (1) ◽  
pp. 75-79 ◽  
Author(s):  
C. Stephen Downes ◽  
Adam S. Wilkins

Cancers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 479
Author(s):  
Pavel Vodicka ◽  
Ladislav Andera ◽  
Alena Opattova ◽  
Ludmila Vodickova

The disruption of genomic integrity due to the accumulation of various kinds of DNA damage, deficient DNA repair capacity, and telomere shortening constitute the hallmarks of malignant diseases. DNA damage response (DDR) is a signaling network to process DNA damage with importance for both cancer development and chemotherapy outcome. DDR represents the complex events that detect DNA lesions and activate signaling networks (cell cycle checkpoint induction, DNA repair, and induction of cell death). TP53, the guardian of the genome, governs the cell response, resulting in cell cycle arrest, DNA damage repair, apoptosis, and senescence. The mutational status of TP53 has an impact on DDR, and somatic mutations in this gene represent one of the critical events in human carcinogenesis. Telomere dysfunction in cells that lack p53-mediated surveillance of genomic integrity along with the involvement of DNA repair in telomeric DNA regions leads to genomic instability. While the role of individual players (DDR, telomere homeostasis, and TP53) in human cancers has attracted attention for some time, there is insufficient understanding of the interactions between these pathways. Since solid cancer is a complex and multifactorial disease with considerable inter- and intra-tumor heterogeneity, we mainly dedicated this review to the interactions of DNA repair, telomere homeostasis, and TP53 mutational status, in relation to (a) cancer risk, (b) cancer progression, and (c) cancer therapy.


2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Andrea Piunti ◽  
Alessandra Rossi ◽  
Aurora Cerutti ◽  
Mareike Albert ◽  
Sriganesh Jammula ◽  
...  

Genetics ◽  
1993 ◽  
Vol 134 (1) ◽  
pp. 63-80 ◽  
Author(s):  
T A Weinert ◽  
L H Hartwell

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.


2021 ◽  
Author(s):  
Meng-Xiang Li ◽  
Xiao-Meng Sun ◽  
Wei-Gang Cheng ◽  
Hao-Jie Ruan ◽  
Ke Liu ◽  
...  

Abstract ObjectiveA plethora of prognostic biomarkers for esophageal squamous cell carcinoma (ESCC) that have hitherto been reported are challenged with low reproducibility due to high molecular heterogeneity of ESCC. The purpose of this study is to identify the optimal biomarkers for ESCC using machine learning algorithms.MethodsBiomarkers related to clinical survival, recurrence or therapeutic response of patients with ESCC were determined through literature database searching. Forty-eight biomarkers linked to prognosis of ESCC were used to construct a molecular interaction network based on NetBox and then to identify the functional modules. Publicably available mRNA transcriptome data of ESCC downloaded from Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) datasets included GSE53625 and TCGA-ESCC. Five machine learning algorithms, including logical regression (LR), support vector machine (SVM), artificial neural network (ANN), random forest (RF) and XGBoost, were used to develop classifiers for prognostic classification for feature selection. The area under ROC curve (AUC) was used to evaluate the performance of the prognostic classifiers. The importances of these 17 molecules were ranked by their occurrence frequencies in the prognostic classifiers. Kaplan-Meier survival analysis and log-rank test were performed to determine the statistical significance of overall survival.ResultsA total of 48 clinical proven molecules associated with ESCC progression were used to construct a molecular interaction network with 3 functional modules comprising 17 component molecules. The 131071 prognostic classifiers using these 17 molecules were built for each machine learning algorithm. Using the occurrence frequencies in the prognostic classifiers with AUCs greater than the mean value of all 131,071 AUCs to rank importances of these 17 molecules, stratifin encoded by SFN was identified as the optimal prognostic biomarker for ESCC, whose performance was further validated in another 2 independent cohorts.ConclusionThe occurrence frequencies across various feature selection approaches reflect the degree of clinical importance and stratifin is an optimal prognostic biomarker for ESCC.


2019 ◽  
Author(s):  
Jacob L. Steenwyk ◽  
Dana A. Opulente ◽  
Jacek Kominek ◽  
Xing-Xing Shen ◽  
Xiaofan Zhou ◽  
...  

AbstractCell cycle checkpoints and DNA repair processes protect organisms from potentially lethal mutational damage. Compared to other budding yeasts in the subphylum Saccharomycotina, we noticed that a lineage in the genus Hanseniaspora exhibited very high evolutionary rates, low GC content, small genome sizes, and lower gene numbers. To better understand Hanseniaspora evolution, we analyzed 25 genomes, including 11 newly sequenced, representing 18 / 21 known species in the genus. Our phylogenomic analyses identify two Hanseniaspora lineages, the fast-evolving lineage (FEL), which began diversifying ∼87 million years ago (mya), and the slow-evolving lineage (SEL), which began diversifying ∼54 mya. Remarkably, both lineages lost genes associated with the cell cycle and genome integrity, but these losses were greater in the FEL. For example, all species lost the cell cycle regulator WHI5, and the FEL lost components of the spindle checkpoint pathway (e.g., MAD1, MAD2) and DNA damage checkpoint pathway (e.g., MEC3, RAD9). Similarly, both lineages lost genes involved in DNA repair pathways, including the DNA glycosylase gene MAG1, which is part of the base excision repair pathway, and the DNA photolyase gene PHR1, which is involved in pyrimidine dimer repair. Strikingly, the FEL lost 33 additional genes, including polymerases (i.e., POL4 and POL32) and telomere-associated genes (e.g., RIF1, RFA3, CDC13, PBP2). Echoing these losses, molecular evolutionary analyses reveal that, compared to the SEL, the FEL stem lineage underwent a burst of accelerated evolution, which resulted in greater mutational loads, homopolymer instabilities, and higher fractions of mutations associated with the common endogenously damaged base, 8-oxoguanine. We conclude that Hanseniaspora is an ancient lineage that has diversified and thrived, despite lacking many otherwise highly conserved cell cycle and genome integrity genes and pathways, and may represent a novel system for studying cellular life without them.


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