scholarly journals Cell Cycle Regulation of DNA Replication Initiator Factor Dbf4p

1999 ◽  
Vol 19 (6) ◽  
pp. 4270-4278 ◽  
Author(s):  
Liang Cheng ◽  
Tim Collyer ◽  
Christopher F. J. Hardy

ABSTRACT The precise duplication of eukaryotic genetic material takes place once and only once per cell cycle and is dependent on the completion of the previous mitosis. Two evolutionarily conserved kinases, the cyclin B (Clb)/cyclin-dependent kinase (Cdk/Cdc28p) and Cdc7p along with its interacting factor Dbf4p, are required late in G1 to initiate DNA replication. We have determined that the levels of Dbf4p are cell cycle regulated. Dbf4p levels increase as cells begin S phase and remain high through late mitosis, after which they decline dramatically as cells begin the next cell cycle. We report that Dbf4p levels are sensitive to mutations in key components of the anaphase-promoting complex (APC). In addition, Dbf4p is modified in response to DNA damage, and this modification is dependent upon the DNA damage response pathway. We had previously shown that Dbf4p interacts with the M phase polo-like kinase Cdc5p, a key regulator of the APC late in mitosis. These results further link the actions of the initiator protein, Dbf4p, to the completion of mitosis and suggest possible roles for Dbf4p during progression through mitosis.

1998 ◽  
Vol 18 (12) ◽  
pp. 7360-7370 ◽  
Author(s):  
Liang Cheng ◽  
Linda Hunke ◽  
Christopher F. J. Hardy

ABSTRACT Progression through and completion of mitosis require the actions of the evolutionarily conserved Polo kinase. We have determined that the levels of Cdc5p, a Saccharomyces cerevisiae member of the Polo family of mitotic kinases, are cell cycle regulated. Cdc5p accumulates in the nuclei of G2/M-phase cells, and its levels decline dramatically as cells progress through anaphase and begin telophase. We report that Cdc5p levels are sensitive to mutations in key components of the anaphase-promoting complex (APC). We have determined that Cdc5p-associated kinase activity is restricted to G2/M and that this activity is posttranslationally regulated. These results further link the actions of the APC to the completion of mitosis and suggest possible roles for Cdc5p during progression through and completion of mitosis.


2020 ◽  
Author(s):  
Stefania Marsili ◽  
Ailone Tichon ◽  
Francesca Storici

AbstractRibonuclease H2 (RNase H2) is a key enzyme for the removal of RNA found in DNA-RNA hybrids, playing a fundamental role in biological processes such as DNA replication, telomere maintenance and DNA damage repair. RNase H2 is a trimer composed of three subunits, being RNASEH2A the catalytic subunit. RNASEH2A expression levels have been shown to be upregulated in transformed and cancer cells. In this study we used a bioinformatics approach to identify RNASEH2A co-expressed genes in different human tissues to uncover biological processes in which RNASEH2A is involved. By implementing this approach, we identified functional networks for RNASEH2A that are not only involved in the processes of DNA replication and DNA damage response, but also in cell cycle regulation. Additional examination of protein-protein networks for RNASEH2A by the STRING database analysis, revealed a high co-expression correlation between RNASEH2A and the genes of the protein networks identified. Mass spectrometry analysis of RNASEH2A-bound proteins highlighted players functioning in cell cycle regulation. Further bioinformatics investigation showed increased gene expression of RNASEH2A in different types of actively cycling cells and tissues, and particularly in several cancers, supporting a biological role for RNASEH2A, but not the other two subunits of RNase H2, in cell proliferation.


2016 ◽  
pp. gkw449 ◽  
Author(s):  
José Antonio Pedroza-Garcia ◽  
Séverine Domenichini ◽  
Christelle Mazubert ◽  
Mickael Bourge ◽  
Charles White ◽  
...  

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Julia Bittmann ◽  
Rokas Grigaitis ◽  
Lorenzo Galanti ◽  
Silas Amarell ◽  
Florian Wilfling ◽  
...  

Cell cycle tags allow to restrict target protein expression to specific cell cycle phases. Here, we present an advanced toolbox of cell cycle tag constructs in budding yeast with defined and compatible peak expression that allow comparison of protein functionality at different cell cycle phases. We apply this technology to the question of how and when Mus81-Mms4 and Yen1 nucleases act on DNA replication or recombination structures. Restriction of Mus81-Mms4 to M phase but not S phase allows a wildtype response to various forms of replication perturbation and DNA damage in S phase, suggesting it acts as a post-replicative resolvase. Moreover, we use cell cycle tags to reinstall cell cycle control to a deregulated version of Yen1, showing that its premature activation interferes with the response to perturbed replication. Curbing resolvase activity and establishing a hierarchy of resolution mechanisms are therefore the principal reasons underlying resolvase cell cycle regulation.


Biology ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 221
Author(s):  
Stefania Marsili ◽  
Ailone Tichon ◽  
Deepali Kundnani ◽  
Francesca Storici

Ribonuclease (RNase) H2 is a key enzyme for the removal of RNA found in DNA-RNA hybrids, playing a fundamental role in biological processes such as DNA replication, telomere maintenance, and DNA damage repair. RNase H2 is a trimer composed of three subunits, RNASEH2A being the catalytic subunit. RNASEH2A expression levels have been shown to be upregulated in transformed and cancer cells. In this study, we used a bioinformatics approach to identify RNASEH2A co-expressed genes in different human tissues to underscore biological processes associated with RNASEH2A expression. Our analysis shows functional networks for RNASEH2A involvement such as DNA replication and DNA damage response and a novel putative functional network of cell cycle regulation. Further bioinformatics investigation showed increased gene expression in different types of actively cycling cells and tissues, particularly in several cancers, supporting a biological role for RNASEH2A but not for the other two subunits of RNase H2 in cell proliferation. Mass spectrometry analysis of RNASEH2A-bound proteins identified players functioning in cell cycle regulation. Additional bioinformatic analysis showed that RNASEH2A correlates with cancer progression and cell cycle related genes in Cancer Cell Line Encyclopedia (CCLE) and The Cancer Genome Atlas (TCGA) Pan Cancer datasets and supported our mass spectrometry findings.


2019 ◽  
Vol 202 (2) ◽  
Author(s):  
Peter E. Burby ◽  
Lyle A. Simmons

ABSTRACT All organisms regulate cell cycle progression by coordinating cell division with DNA replication status. In eukaryotes, DNA damage or problems with replication fork progression induce the DNA damage response (DDR), causing cyclin-dependent kinases to remain active, preventing further cell cycle progression until replication and repair are complete. In bacteria, cell division is coordinated with chromosome segregation, preventing cell division ring formation over the nucleoid in a process termed nucleoid occlusion. In addition to nucleoid occlusion, bacteria induce the SOS response after replication forks encounter DNA damage or impediments that slow or block their progression. During SOS induction, Escherichia coli expresses a cytoplasmic protein, SulA, that inhibits cell division by directly binding FtsZ. After the SOS response is turned off, SulA is degraded by Lon protease, allowing for cell division to resume. Recently, it has become clear that SulA is restricted to bacteria closely related to E. coli and that most bacteria enforce the DNA damage checkpoint by expressing a small integral membrane protein. Resumption of cell division is then mediated by membrane-bound proteases that cleave the cell division inhibitor. Further, many bacterial cells have mechanisms to inhibit cell division that are regulated independently from the canonical LexA-mediated SOS response. In this review, we discuss several pathways used by bacteria to prevent cell division from occurring when genome instability is detected or before the chromosome has been fully replicated and segregated.


2021 ◽  
Vol 22 (10) ◽  
pp. 5195
Author(s):  
Hui Zhang

In eukaryotic cells, DNA replication licensing is precisely regulated to ensure that the initiation of genomic DNA replication in S phase occurs once and only once for each mitotic cell division. A key regulatory mechanism by which DNA re-replication is suppressed is the S phase-dependent proteolysis of Cdt1, an essential replication protein for licensing DNA replication origins by loading the Mcm2-7 replication helicase for DNA duplication in S phase. Cdt1 degradation is mediated by CRL4Cdt2 ubiquitin E3 ligase, which further requires Cdt1 binding to proliferating cell nuclear antigen (PCNA) through a PIP box domain in Cdt1 during DNA synthesis. Recent studies found that Cdt2, the specific subunit of CRL4Cdt2 ubiquitin E3 ligase that targets Cdt1 for degradation, also contains an evolutionarily conserved PIP box-like domain that mediates the interaction with PCNA. These findings suggest that the initiation and elongation of DNA replication or DNA damage-induced repair synthesis provide a novel mechanism by which Cdt1 and CRL4Cdt2 are both recruited onto the trimeric PCNA clamp encircling the replicating DNA strands to promote the interaction between Cdt1 and CRL4Cdt2. The proximity of PCNA-bound Cdt1 to CRL4Cdt2 facilitates the destruction of Cdt1 in response to DNA damage or after DNA replication initiation to prevent DNA re-replication in the cell cycle. CRL4Cdt2 ubiquitin E3 ligase may also regulate the degradation of other PIP box-containing proteins, such as CDK inhibitor p21 and histone methylase Set8, to regulate DNA replication licensing, cell cycle progression, DNA repair, and genome stability by directly interacting with PCNA during DNA replication and repair synthesis.


Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 129
Author(s):  
Hae Ryung Chang ◽  
Eunyoung Jung ◽  
Soobin Cho ◽  
Young-Jun Jeon ◽  
Yonghwan Kim

While Next-Generation Sequencing (NGS) and technological advances have been useful in identifying genetic profiles of tumorigenesis, novel target proteins and various clinical biomarkers, cancer continues to be a major global health threat. DNA replication, DNA damage response (DDR) and repair, and cell cycle regulation continue to be essential systems in targeted cancer therapies. Although many genes involved in DDR are known to be tumor suppressor genes, cancer cells are often dependent and addicted to these genes, making them excellent therapeutic targets. In this review, genes implicated in DNA replication, DDR, DNA repair, cell cycle regulation are discussed with reference to peptide or small molecule inhibitors which may prove therapeutic in cancer patients. Additionally, the potential of utilizing novel synthetic lethal genes in these pathways is examined, providing possible new targets for future therapeutics. Specifically, we evaluate the potential of TONSL as a novel gene for targeted therapy. Although it is a scaffold protein with no known enzymatic activity, the strategy used for developing PCNA inhibitors can also be utilized to target TONSL. This review summarizes current knowledge on non-oncogene addiction, and the utilization of synthetic lethality for developing novel inhibitors targeting non-oncogenic addiction for cancer therapy.


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