1
|
Zhang L, Hong J, Chen W, Zhang W, Liu X, Lu J, Tang H, Yang Z, Zhou K, Xie H, Jia C, Jiang D, Zheng S. DBF4 Dependent Kinase Inhibition Suppresses Hepatocellular Carcinoma Progression and Potentiates Anti-Programmed Cell Death-1 Therapy. Int J Biol Sci 2023; 19:3412-3427. [PMID: 37497004 PMCID: PMC10367558 DOI: 10.7150/ijbs.80351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 06/13/2023] [Indexed: 07/28/2023] Open
Abstract
The progression of hepatocellular carcinoma (HCC) remains a huge clinical challenge, and elucidation of the underlying molecular mechanisms is critical to develop effective therapeutic strategy. Dumbbell former 4 (DBF4) complexes with cell division cycle 7 (CDC7) to form DBF4-dependent kinase (DDK), playing instrumental roles in tumor cell survival, whereas its roles in HCC remain elusive. This study revealed that DBF4 expression was upregulated in HCC and constituted an independent prognostic factor of patient survival. We identified p65 as an upstream inducer which increased DBF4 expression by directly binding to its promoter. DBF4 accelerated HCC cell proliferation and tumorigenesis in vitro and in vivo. Mechanistically, DBF4 complexed with CDC7 to bind to the coiled coil domain of STAT3 and activate STAT3 signaling through XPO1-mediated nuclear exportation. Notably, p65 enhanced the nuclear transport of DDK and DDK-STAT3 interaction by transcriptionally upregulating XPO1. DBF4 expression positively correlated with activated STAT3 and XPO1 in HCC tissues. Furthermore, combining DDK inhibitor XL413 with anti-PD-1 immunotherapy dramatically suppressed HCC growth and prolonged the survival of HCC-bearing mouse. Our findings reveal that DDK activates STAT3 pathway and facilitates HCC progression, and demonstrate the proof of the concept of targeting DDK to improve the efficacy of HCC immunotherapy.
Collapse
Affiliation(s)
- Liang Zhang
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Organ Transplantation, NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China
| | - Jiawei Hong
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Organ Transplantation, NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China
| | - Wei Chen
- Department of Hepatobiliary and Pancreatic Surgery, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Research Center of Diagnosis and Treatment Technology for Hepatocellular Carcinoma of Zhejiang Province, Hangzhou, China
| | - Wei Zhang
- Department of Medical Oncology, Sir Runrun Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Xi Liu
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Organ Transplantation, NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China
| | - Jiahua Lu
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Organ Transplantation, NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China
| | - Hong Tang
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Organ Transplantation, NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China
| | - Zhentao Yang
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Organ Transplantation, NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China
| | - Ke Zhou
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Organ Transplantation, NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China
| | - Haiyang Xie
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Organ Transplantation, NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China
| | - Changku Jia
- Department of Hepatobiliary and Pancreatic Surgery, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Research Center of Diagnosis and Treatment Technology for Hepatocellular Carcinoma of Zhejiang Province, Hangzhou, China
| | - Donghai Jiang
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Organ Transplantation, NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China
| | - Shusen Zheng
- Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Organ Transplantation, NHC Key Laboratory of Combined Multi-organ Transplantation, Hangzhou, China
| |
Collapse
|
2
|
Li N, Gao N, Zhai Y. DDK promotes DNA replication initiation: Mechanistic and structural insights. Curr Opin Struct Biol 2023; 78:102504. [PMID: 36525878 DOI: 10.1016/j.sbi.2022.102504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/25/2022] [Accepted: 11/15/2022] [Indexed: 12/15/2022]
Abstract
DNA replication initiation in eukaryotes is tightly regulated through two cell-cycle specific processes, replication licensing to install inactive minichromosome maintenance (MCM) double-hexamers (DH) on origins in early G1 phase and origin firing to assemble and activate Cdc45-Mcm2-7-GINS (CMG) helicases upon S phase entry. Two kinases, cyclin-dependent kinase (CDK) and Dbf4-dependent kinase (DDK), are responsible for driving the association of replication factors with the MCM-DH to form CMG helicases for origin melting and DNA unwinding and eventually replisomes for bi-directional DNA synthesis. In recent years, cryo-electron microscopy studies have generated a collection of structural snapshots for the stepwise assembly and remodeling of the replication initiation machineries, creating a framework for understanding the regulation of this fundamental process at a molecular level. Very recent progress is the structural characterization of the elusive MCM-DH-DDK complex, which provides insights into mechanisms of kinase activation, substrate recognition and selection, as well as molecular role of DDK-mediated MCM-DH phosphorylation in helicase activation.
Collapse
Affiliation(s)
- Ningning Li
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Ning Gao
- State Key Laboratory of Membrane Biology, Peking-Tsinghua Joint Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China; National Biomedical Imaging Center, Peking University, Beijing, China.
| | - Yuanliang Zhai
- School of Biological Sciences, The University of Hong Kong, Hong Kong.
| |
Collapse
|
3
|
Ziegler W, Schölderle T, Brendel B, Risch V, Felber S, Ott K, Goldenberg G, Vogel M, Bötzel K, Zettl L, Lorenzl S, Lampe R, Strecker K, Synofzik M, Lindig T, Ackermann H, Staiger A. Speech and Nonspeech Parameters in the Clinical Assessment of Dysarthria: A Dimensional Analysis. Brain Sci 2023; 13:brainsci13010113. [PMID: 36672094 PMCID: PMC9856358 DOI: 10.3390/brainsci13010113] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Revised: 01/03/2023] [Accepted: 01/05/2023] [Indexed: 01/11/2023] Open
Abstract
Nonspeech (or paraspeech) parameters are widely used in clinical assessment of speech impairment in persons with dysarthria (PWD). Virtually every standard clinical instrument used in dysarthria diagnostics includes nonspeech parameters, often in considerable numbers. While theoretical considerations have challenged the validity of these measures as markers of speech impairment, only a few studies have directly examined their relationship to speech parameters on a broader scale. This study was designed to investigate how nonspeech parameters commonly used in clinical dysarthria assessment relate to speech characteristics of dysarthria in individuals with movement disorders. Maximum syllable repetition rates, accuracies, and rates of isolated and repetitive nonspeech oral-facial movements and maximum phonation times were compared with auditory-perceptual and acoustic speech parameters. Overall, 23 diagnostic parameters were assessed in a sample of 130 patients with movement disorders of six etiologies. Each variable was standardized for its distribution and for age and sex effects in 130 neurotypical speakers. Exploratory Graph Analysis (EGA) and Confirmatory Factor Analysis (CFA) were used to examine the factor structure underlying the diagnostic parameters. In the first analysis, we tested the hypothesis that nonspeech parameters combine with speech parameters within diagnostic dimensions representing domain-general motor control principles. In a second analysis, we tested the more specific hypotheses that diagnostic parameters split along effector (lip vs. tongue) or functional (speed vs. accuracy) rather than task boundaries. Our findings contradict the view that nonspeech parameters currently used in dysarthria diagnostics are congruent with diagnostic measures of speech characteristics in PWD.
Collapse
Affiliation(s)
- Wolfram Ziegler
- Clinical Neuropsychology Research Group (EKN), Institute of Phonetics and Speech Processing, Ludwig-Maximilians-University, 80799 Munich, Germany
- Correspondence:
| | - Theresa Schölderle
- Clinical Neuropsychology Research Group (EKN), Institute of Phonetics and Speech Processing, Ludwig-Maximilians-University, 80799 Munich, Germany
| | - Bettina Brendel
- Clinic for Psychiatry and Psychotherapy, Neurophysiology & Interventional Neuropsychiatry, University of Tübingen, 72076 Tübingen, Germany
| | - Verena Risch
- Clinical Neuropsychology Research Group (EKN), Institute of Phonetics and Speech Processing, Ludwig-Maximilians-University, 80799 Munich, Germany
| | - Stefanie Felber
- Clinical Neuropsychology Research Group (EKN), Institute of Phonetics and Speech Processing, Ludwig-Maximilians-University, 80799 Munich, Germany
| | - Katharina Ott
- Department of Neurology, Klinikum Großhadern, Ludwig-Maximilians-University, 81377 Munich, Germany
| | - Georg Goldenberg
- Clinic for Neuropsychology, City Hospital Munich Bogenhausen, 81925 Munich, Germany
| | - Mathias Vogel
- Clinic for Neuropsychology, City Hospital Munich Bogenhausen, 81925 Munich, Germany
| | - Kai Bötzel
- Department of Neurology, Klinikum Großhadern, Ludwig-Maximilians-University, 81377 Munich, Germany
| | - Lena Zettl
- Medical Clinic and Outpatient Clinic IV, Ludwig-Maximilians-University, 81377 Munich, Germany
| | - Stefan Lorenzl
- Clinic for Neurology, Hospital Agatharied, 83734 Hausham, Germany
| | - Renée Lampe
- School of Medicine, Klinikum Rechts der Isar, Orthopedic Department, Research Unit for Pediatric Neuroorthopedics and Cerebral Palsy of the Buhl-Strohmaier Foundation, Technical University of Munich, 81675 Munich, Germany
| | - Katrin Strecker
- Department of Logopedics, Stiftung ICP Munich, Center for Cerebral Palsy, 81377 Munich, Germany
| | - Matthis Synofzik
- Department of Neurodegenerative Disease, Hertie-Institute for Clinical Brain Research, German Center for Neurodegenerative Diseases (DZNE), and Center for Neurology, University of Tübingen, 72076 Tübingen, Germany
| | - Tobias Lindig
- Department of Diagnostic and Interventional Neuroradiology, University Hospital Tübingen, 72076 Tübingen, Germany
| | - Hermann Ackermann
- Department of General Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany
| | - Anja Staiger
- Clinical Neuropsychology Research Group (EKN), Institute of Phonetics and Speech Processing, Ludwig-Maximilians-University, 80799 Munich, Germany
| |
Collapse
|
4
|
Wang M, Qiu ZH, Wang YZ, Lian B, Bai JK, Zhou YJ, Ji HJ. Analysis of the expression and prognostic significance of DDK complex in Hepatocarcinoma. BMC Cancer 2023; 23:19. [PMID: 36609254 PMCID: PMC9817372 DOI: 10.1186/s12885-022-10475-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 12/22/2022] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Hepatocellular carcinoma (HCC) remains one of the most common and lethal malignancies worldwide. Although DBF4-dependent kinase (DDK) complex composed of CDC7 kinase and its regulatory subunit DBF4 has been shown to be overexpressed in primary tumors and promotes tumor development, while its role and prognostic value in HCC remain largely unknown. In the present study, the expression of DBF4 and CDC7 and their relationship with clinical characteristics were comprehensively analyzed. METHODS The mRNA expression profiles of HCC and the corresponding clinical data of HCC patients were downloaded from TCGA and GEO databases, respectively. The differences in DBF4 and CDC7 expression in tumor tissues and adjacent normal tissues were analyzed. HCC-derived tissue microarray (TMA) was used to evaluate and score the expression of CDC7 by immunohistochemistry (IHC) staining. The Kaplan-Meier method and the Cox regression method were used to analyze the relationship between overall survival and clinical characteristics of the patients. Gene set enrichment analysis (GSEA) was used to analyze the pathway enrichment of DBF4 and CDC7. RESULTS DBF4 and CDC7 had similar expression patterns in HCC patients. Detailly, compared with adjacent tissues, both mRNA and protein of DBF4 and CDC7 were significantly higher in HCC, and their expression was positively correlated with AJCC_T stage, clinical stage and G stage (grade) of liver cancer patients, and higher DBF4 or CDC7 expression predicted a worse prognosis in HCC patients with shorter overall survival (OS), recurrence-free survival (RFS), disease-specific survival (DSS) and progress-free survival (PFS). Cox regression analysis suggested that both DBF4 and CDC7 were independent risk factors for the prognosis of HCC patients in TCGA dataset. GSEA suggested that both DBF4 and CDC7 were positively correlated with cell cycle and DNA replication. Finally, the prognostic value of CDC7 was furtherly confirmed by TMA-based IHC staining results. CONCLUSIONS Our study showed that DDK complex was significantly increased in HCC. Both DBF4 and CDC7 may be potential diagnostic and prognostic markers for HCC, and high expression of DDK members predicts a worse prognosis in patients with HCC, which may be associated with high tumor cell proliferation rate.
Collapse
Affiliation(s)
- Min Wang
- grid.268079.20000 0004 1790 6079School of Life Science and Technology, Weifang Medical University, No.7166, Baotongxi Street, Weifang, 261053 China
| | - Zu-Hua Qiu
- grid.268079.20000 0004 1790 6079School of Life Science and Technology, Weifang Medical University, No.7166, Baotongxi Street, Weifang, 261053 China
| | - Yu-Zhuo Wang
- grid.268079.20000 0004 1790 6079School of Life Science and Technology, Weifang Medical University, No.7166, Baotongxi Street, Weifang, 261053 China
| | - Bo Lian
- grid.268079.20000 0004 1790 6079School of Life Science and Technology, Weifang Medical University, No.7166, Baotongxi Street, Weifang, 261053 China
| | - Jing-Kun Bai
- grid.268079.20000 0004 1790 6079School of Life Science and Technology, Weifang Medical University, No.7166, Baotongxi Street, Weifang, 261053 China
| | - Yong-Jie Zhou
- grid.412901.f0000 0004 1770 1022Laboratory of Liver Transplantation, West China Hospital, Sichuan University, No.1, Keyuan 4 Road, Chengdu, 610041 China
| | - Hong-Jie Ji
- grid.268079.20000 0004 1790 6079School of Life Science and Technology, Weifang Medical University, No.7166, Baotongxi Street, Weifang, 261053 China
| |
Collapse
|
5
|
Cho CY, Seller CA, O’Farrell PH. Temporal control of late replication and coordination of origin firing by self-stabilizing Rif1-PP1 hubs in Drosophila. Proc Natl Acad Sci U S A 2022; 119:e2200780119. [PMID: 35733247 PMCID: PMC9245680 DOI: 10.1073/pnas.2200780119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 05/19/2022] [Indexed: 12/25/2022] Open
Abstract
In the metazoan S phase, coordinated firing of clusters of origins replicates different parts of the genome in a temporal program. Despite advances, neither the mechanism controlling timing nor that coordinating firing of multiple origins is fully understood. Rif1, an evolutionarily conserved inhibitor of DNA replication, recruits protein phosphatase 1 (PP1) and counteracts firing of origins by S-phase kinases. During the midblastula transition (MBT) in Drosophila embryos, Rif1 forms subnuclear hubs at each of the large blocks of satellite sequences and delays their replication. Each Rif1 hub disperses abruptly just prior to the replication of the associated satellite sequences. Here, we show that the level of activity of the S-phase kinase, DDK, accelerated this dispersal program, and that the level of Rif1-recruited PP1 retarded it. Further, Rif1-recruited PP1 supported chromatin association of nearby Rif1. This influence of nearby Rif1 can create a "community effect" counteracting kinase-induced dissociation such that an entire hub of Rif1 undergoes switch-like dispersal at characteristic times that shift in response to the balance of Rif1-PP1 and DDK activities. We propose a model in which the spatiotemporal program of late replication in the MBT embryo is controlled by self-stabilizing Rif1-PP1 hubs, whose abrupt dispersal synchronizes firing of associated late origins.
Collapse
Affiliation(s)
- Chun-Yi Cho
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158
| | - Charles A. Seller
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158
| | - Patrick H. O’Farrell
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158
| |
Collapse
|
6
|
Martin JC, Sims JR, Gupta A, Bakin AV, Ohm JE. WEE1 inhibition augments CDC7 ( DDK) inhibitor-induced cell death in Ewing sarcoma by forcing premature mitotic entry and mitotic catastrophe. Cancer Res Commun 2022; 2:471-482. [PMID: 36338546 PMCID: PMC9635308 DOI: 10.1158/2767-9764.crc-22-0130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 04/08/2022] [Accepted: 05/25/2022] [Indexed: 06/16/2023]
Abstract
Ewing sarcoma is an aggressive childhood cancer for which treatment options remain limited and toxic. There is an urgent need for the identification of novel therapeutic strategies. Our group has recently shown that Ewing cells rely on the S-phase kinase CDC7 (DDK) to maintain replication rates and cell viability and that DDK inhibition causes an increase in the phosphorylation of CDK1 and a significant delay in mitotic entry. Here, we expand on our previous findings and show that DDK inhibitor-induced mitotic entry delay is dependent upon WEE1 kinase. Specifically, WEE1 phosphorylates CDK1 and prevents mitotic entry upon DDK inhibition due to the presence of under-replicated DNA, potentially limiting the cytotoxic effects of DDK inhibition. To overcome this, we combined the inhibition of DDK with the inhibition of WEE1 and found that this results in elevated levels of premature mitotic entry, mitotic catastrophe, and apoptosis. Importantly, we have found that DDK and WEE1 inhibitors display a synergistic relationship with regards to reducing cell viability of Ewing sarcoma cells. Interestingly, the cytotoxic nature of this combination can be suppressed by the inhibition of CDK1 or microtubule polymerization, indicating that mitotic progression is required to elicit the cytotoxic effects. This is the first study to display the potential of utilizing the combined inhibition of DDK and WEE1 for the treatment of cancer. We believe this will offer a potential therapeutic strategy for the treatment of Ewing sarcoma as well as other tumor types that display sensitivity to DDK inhibitors.
Collapse
Affiliation(s)
- Jeffrey C. Martin
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, New York
| | - Jennie R. Sims
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, New York
| | - Ajay Gupta
- Division of Pediatric Oncology, Roswell Park Comprehensive Cancer Center, Department of Pediatrics, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York
| | - Andrei V. Bakin
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, New York
| | - Joyce Ellen Ohm
- Department of Cancer Genetics and Genomics, Roswell Park Comprehensive Cancer Center, Buffalo, New York
| |
Collapse
|
7
|
Volpi I, Gillespie PJ, Chadha GS, Blow JJ. The role of DDK and Treslin-MTBP in coordinating replication licensing and pre-initiation complex formation. Open Biol 2021; 11:210121. [PMID: 34699733 PMCID: PMC8548084 DOI: 10.1098/rsob.210121] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 09/21/2021] [Indexed: 01/04/2023] Open
Abstract
Treslin/Ticrr is required for the initiation of DNA replication and binds to MTBP (Mdm2 Binding Protein). Here, we show that in Xenopus egg extract, MTBP forms an elongated tetramer with Treslin containing two molecules of each protein. Immunodepletion and add-back experiments show that Treslin-MTBP is rate limiting for replication initiation. It is recruited onto chromatin before S phase starts and recruitment continues during S phase. We show that DDK activity both increases and strengthens the interaction of Treslin-MTBP with licensed chromatin. We also show that DDK activity cooperates with CDK activity to drive the interaction of Treslin-MTBP with TopBP1 which is a regulated crucial step in pre-initiation complex formation. These results suggest how DDK works together with CDKs to regulate Treslin-MTBP and plays a crucial in selecting which origins will undergo initiation.
Collapse
Affiliation(s)
- Ilaria Volpi
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Peter J. Gillespie
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Gaganmeet Singh Chadha
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - J. Julian Blow
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| |
Collapse
|
8
|
Klemm C, Thorpe PH, Ólafsson G. Cell-cycle phospho-regulation of the kinetochore. Curr Genet 2021; 67:177-93. [PMID: 33221975 DOI: 10.1007/s00294-020-01127-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/27/2020] [Accepted: 10/29/2020] [Indexed: 02/07/2023]
Abstract
The kinetochore is a mega-dalton protein assembly that forms within centromeric regions of chromosomes and directs their segregation during cell division. Here we review cell cycle-mediated phosphorylation events at the kinetochore, with a focus on the budding yeast Saccharomyces cerevisiae and the insight gained from forced associations of kinases and phosphatases. The point centromeres found in the budding yeast S. cerevisiae are one of the simplest such structures found in eukaryotes. The S. cerevisiae kinetochore comprises a single nucleosome, containing a centromere-specific H3 variant Cse4CENP-A, bound to a set of kinetochore proteins that connect to a single microtubule. Despite the simplicity of the budding yeast kinetochore, the proteins are mostly homologous with their mammalian counterparts. In some cases, human proteins can complement their yeast orthologs. Like its mammalian equivalent, the regulation of the budding yeast kinetochore is complex: integrating signals from the cell cycle, checkpoints, error correction, and stress pathways. The regulatory signals from these diverse pathways are integrated at the kinetochore by post-translational modifications, notably phosphorylation and dephosphorylation, to control chromosome segregation. Here we highlight the complex interplay between the activity of the different cell-cycle kinases and phosphatases at the kinetochore, emphasizing how much more we have to understand this essential structure.
Collapse
|
9
|
Jones MJK, Gelot C, Munk S, Koren A, Kawasoe Y, George KA, Santos RE, Olsen JV, McCarroll SA, Frattini MG, Takahashi TS, Jallepalli PV. Human DDK rescues stalled forks and counteracts checkpoint inhibition at unfired origins to complete DNA replication. Mol Cell 2021; 81:426-441.e8. [PMID: 33545059 DOI: 10.1016/j.molcel.2021.01.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 09/25/2020] [Accepted: 01/05/2021] [Indexed: 12/14/2022]
Abstract
Eukaryotic genomes replicate via spatially and temporally regulated origin firing. Cyclin-dependent kinase (CDK) and Dbf4-dependent kinase (DDK) promote origin firing, whereas the S phase checkpoint limits firing to prevent nucleotide and RPA exhaustion. We used chemical genetics to interrogate human DDK with maximum precision, dissect its relationship with the S phase checkpoint, and identify DDK substrates. We show that DDK inhibition (DDKi) leads to graded suppression of origin firing and fork arrest. S phase checkpoint inhibition rescued origin firing in DDKi cells and DDK-depleted Xenopus egg extracts. DDKi also impairs RPA loading, nascent-strand protection, and fork restart. Via quantitative phosphoproteomics, we identify the BRCA1-associated (BRCA1-A) complex subunit MERIT40 and the cohesin accessory subunit PDS5B as DDK effectors in fork protection and restart. Phosphorylation neutralizes autoinhibition mediated by intrinsically disordered regions in both substrates. Our results reveal mechanisms through which DDK controls the duplication of large vertebrate genomes.
Collapse
Affiliation(s)
- Mathew J K Jones
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; The University of Queensland Diamantina Institute, The University of Queensland, Woolloongabba, QLD 4102, Australia.
| | - Camille Gelot
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Stephanie Munk
- University of Copenhagen and Novo Nordisk Foundation Center for Protein Research, Copenhagen 2200, Denmark
| | - Amnon Koren
- Cornell University, Department of Molecular Biology and Genetics, Ithaca, NY 14853, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Yoshitaka Kawasoe
- Graduate School of Science, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - Kelly A George
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Ruth E Santos
- Division of Hematology/Oncology, Columbia University Medical Center, New York, NY 10032, USA
| | - Jesper V Olsen
- University of Copenhagen and Novo Nordisk Foundation Center for Protein Research, Copenhagen 2200, Denmark
| | | | - Mark G Frattini
- Division of Hematology/Oncology, Columbia University Medical Center, New York, NY 10032, USA
| | - Tatsuro S Takahashi
- Graduate School of Science, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - Prasad V Jallepalli
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
| |
Collapse
|
10
|
Abstract
Eukaryotic replication origins are licensed by the loading of the replicative DNA helicase, Mcm2-7, in inactive double hexameric form around DNA. Subsequent origin activation is under control of multiple protein kinases that either promote or inhibit origin activation, which is important for genome maintenance. Using the reconstituted budding yeast DNA replication system, we find that the flexible N-terminal extension (NTE) of Mcm2 promotes the stable recruitment of Dbf4-dependent kinase (DDK) to Mcm2-7 double hexamers, which in turn promotes DDK phosphorylation of Mcm4 and −6 and subsequent origin activation. Conversely, we demonstrate that the checkpoint kinase, Rad53, inhibits DDK binding to Mcm2-7 double hexamers. Unexpectedly, this function is not dependent on Rad53 kinase activity, suggesting steric inhibition of DDK by activated Rad53. These findings identify critical determinants of the origin activation reaction and uncover a novel mechanism for checkpoint-dependent origin inhibition.
Collapse
Affiliation(s)
- Syafiq Abd Wahab
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States.,Weill-Cornell Graduate School of Medical Sciences, New York, United States
| | - Dirk Remus
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, United States.,Weill-Cornell Graduate School of Medical Sciences, New York, United States
| |
Collapse
|
11
|
Nathanailidou P, Taraviras S, Lygerou Z. Chromatin and Nuclear Architecture: Shaping DNA Replication in 3D. Trends Genet 2020; 36:967-80. [PMID: 32713597 DOI: 10.1016/j.tig.2020.07.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/26/2020] [Accepted: 07/02/2020] [Indexed: 12/13/2022]
Abstract
In eukaryotes, DNA replication progresses through a finely orchestrated temporal and spatial program. The 3D genome structure and nuclear architecture have recently emerged as fundamental determinants of the replication program. Factors with established roles in replication have been recognized as genome organization regulators. Exploiting paradigms from yeasts and mammals, we discuss how DNA replication is regulated in time and space through DNA-associated trans-acting factors, diffusible limiting replication initiation factors, higher-order chromatin folding, dynamic origin localization, and specific nuclear microenvironments. We present an integrated model for the regulation of DNA replication in 3D and highlight the importance of accurate spatio-temporal regulation of DNA replication in physiology and disease.
Collapse
|
12
|
Dick SD, Federico S, Hughes SM, Pye VE, O'Reilly N, Cherepanov P. Structural Basis for the Activation and Target Site Specificity of CDC7 Kinase. Structure 2020; 28:954-962.e4. [PMID: 32521228 DOI: 10.1016/j.str.2020.05.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 05/11/2020] [Accepted: 05/19/2020] [Indexed: 12/13/2022]
Abstract
CDC7 is an essential Ser/Thr kinase that acts upon the replicative helicase throughout the S phase of the cell cycle and is activated by DBF4. Here, we present crystal structures of a highly active human CDC7-DBF4 construct. The structures reveal a zinc-finger domain at the end of the kinase insert 2 that pins the CDC7 activation loop to motif M of DBF4 and the C lobe of CDC7. These interactions lead to ordering of the substrate-binding platform and full opening of the kinase active site. In a co-crystal structure with a mimic of MCM2 Ser40 phosphorylation target, the invariant CDC7 residues Arg373 and Arg380 engage phospho-Ser41 at substrate P+1 position, explaining the selectivity of the S-phase kinase for Ser/Thr residues followed by a pre-phosphorylated or an acidic residue. Our results clarify the role of DBF4 in activation of CDC7 and elucidate the structural basis for recognition of its preferred substrates. DBF4 activates CDC7 kinase via a two-step mechanism Zinc-finger domain in CDC7 KI2 interacts with DBF4 motif M Invariant CDC7 residues Arg373 and Arg380 engage P+1 substrate site
Collapse
|
13
|
Eisenstatt JR, Boeckmann L, Au WC, Garcia V, Bursch L, Ocampo J, Costanzo M, Weinreich M, Sclafani RA, Baryshnikova A, Myers CL, Boone C, Clark DJ, Baker R, Basrai MA. Dbf4-Dependent Kinase ( DDK)-Mediated Proteolysis of CENP-A Prevents Mislocalization of CENP-A in Saccharomyces cerevisiae. G3 (Bethesda) 2020; 10:2057-68. [PMID: 32295767 DOI: 10.1534/g3.120.401131] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The evolutionarily conserved centromeric histone H3 variant (Cse4 in budding yeast, CENP-A in humans) is essential for faithful chromosome segregation. Mislocalization of CENP-A to non-centromeric chromatin contributes to chromosomal instability (CIN) in yeast, fly, and human cells and CENP-A is highly expressed and mislocalized in cancers. Defining mechanisms that prevent mislocalization of CENP-A is an area of active investigation. Ubiquitin-mediated proteolysis of overexpressed Cse4 (GALCSE4) by E3 ubiquitin ligases such as Psh1 prevents mislocalization of Cse4, and psh1 Δ strains display synthetic dosage lethality (SDL) with GALCSE4 We previously performed a genome-wide screen and identified five alleles of CDC7 and DBF4 that encode the Dbf4-dependent kinase (DDK) complex, which regulates DNA replication initiation, among the top twelve hits that displayed SDL with GALCSE4 We determined that cdc7 -7 strains exhibit defects in ubiquitin-mediated proteolysis of Cse4 and show mislocalization of Cse4 Mutation of MCM5 (mcm5 -bob1) bypasses the requirement of Cdc7 for replication initiation and rescues replication defects in a cdc7 -7 strain. We determined that mcm5 -bob1 does not rescue the SDL and defects in proteolysis of GALCSE4 in a cdc7 -7 strain, suggesting a DNA replication-independent role for Cdc7 in Cse4 proteolysis. The SDL phenotype, defects in ubiquitin-mediated proteolysis, and the mislocalization pattern of Cse4 in a cdc7 -7 psh1 Δ strain were similar to that of cdc7 -7 and psh1 Δ strains, suggesting that Cdc7 regulates Cse4 in a pathway that overlaps with Psh1 Our results define a DNA replication initiation-independent role of DDK as a regulator of Psh1-mediated proteolysis of Cse4 to prevent mislocalization of Cse4.
Collapse
|
14
|
Mastro TL, Tripathi VP, Forsburg SL. Translesion synthesis polymerases contribute to meiotic chromosome segregation and cohesin dynamics in Schizosaccharomycespombe. J Cell Sci 2020; 133:jcs238709. [PMID: 32317395 PMCID: PMC7325440 DOI: 10.1242/jcs.238709] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 03/26/2020] [Indexed: 12/17/2022] Open
Abstract
Translesion synthesis polymerases (TLSPs) are non-essential error-prone enzymes that ensure cell survival by facilitating DNA replication in the presence of DNA damage. In addition to their role in bypassing lesions, TLSPs have been implicated in meiotic double-strand break repair in several systems. Here, we examine the joint contribution of four TLSPs to meiotic progression in the fission yeast Schizosaccharomyces pombe. We observed a dramatic loss of spore viability in fission yeast lacking all four TLSPs, which is accompanied by disruptions in chromosome segregation during meiosis I and II. Rec8 cohesin dynamics are altered in the absence of the TLSPs. These data suggest that the TLSPs contribute to multiple aspects of meiotic chromosome dynamics.
Collapse
Affiliation(s)
- Tara L Mastro
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089-2910, USA
| | - Vishnu P Tripathi
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089-2910, USA
| | - Susan L Forsburg
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089-2910, USA
| |
Collapse
|
15
|
Psakhye I, Castellucci F, Branzei D. SUMO-Chain-Regulated Proteasomal Degradation Timing Exemplified in DNA Replication Initiation. Mol Cell 2019; 76:632-645.e6. [PMID: 31519521 PMCID: PMC6891891 DOI: 10.1016/j.molcel.2019.08.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 07/01/2019] [Accepted: 08/01/2019] [Indexed: 11/18/2022]
Abstract
Similar to ubiquitin, SUMO forms chains, but the identity of SUMO-chain-modified factors and the purpose of this modification remain largely unknown. Here, we identify the budding yeast SUMO protease Ulp2, able to disassemble SUMO chains, as a DDK interactor enriched at replication origins that promotes DNA replication initiation. Replication-engaged DDK is SUMOylated on chromatin, becoming a degradation-prone substrate when Ulp2 no longer protects it against SUMO chain assembly. Specifically, SUMO chains channel DDK for SUMO-targeted ubiquitin ligase Slx5/Slx8-mediated and Cdc48 segregase-assisted proteasomal degradation. Importantly, the SUMOylation-defective ddk-KR mutant rescues inefficient replication onset and MCM activation in cells lacking Ulp2, suggesting that SUMO chains time DDK degradation. Using two unbiased proteomic approaches, we further identify subunits of the MCM helicase and other factors as SUMO-chain-modified degradation-prone substrates of Ulp2 and Slx5/Slx8. We thus propose SUMO-chain/Ulp2-protease-regulated proteasomal degradation as a mechanism that times the availability of functionally engaged SUMO-modified protein pools during replication and beyond.
Collapse
Affiliation(s)
- Ivan Psakhye
- IFOM, FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
| | | | - Dana Branzei
- IFOM, FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy; Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), Via Abbiategrasso 207, 27100 Pavia, Italy.
| |
Collapse
|
16
|
Galander S, Barton RE, Borek WE, Spanos C, Kelly DA, Robertson D, Rappsilber J, Marston AL. Reductional Meiosis I Chromosome Segregation Is Established by Coordination of Key Meiotic Kinases. Dev Cell 2019; 49:526-541.e5. [PMID: 31031198 PMCID: PMC6547162 DOI: 10.1016/j.devcel.2019.04.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 12/05/2018] [Accepted: 03/31/2019] [Indexed: 02/07/2023]
Abstract
Meiosis produces gametes through a specialized, two-step cell division, which is highly error prone in humans. Reductional meiosis I, where maternal and paternal chromosomes (homologs) segregate, is followed by equational meiosis II, where sister chromatids separate. Uniquely during meiosis I, sister kinetochores are monooriented and pericentromeric cohesin is protected. Here, we demonstrate that these key adaptations for reductional chromosome segregation are achieved through separable control of multiple kinases by the meiosis-I-specific budding yeast Spo13 protein. Recruitment of Polo kinase to kinetochores directs monoorientation, while independently, cohesin protection is achieved by containing the effects of cohesin kinases. Therefore, reductional chromosome segregation, the defining feature of meiosis, is established by multifaceted kinase control by a master regulator. The recent identification of Spo13 orthologs, fission yeast Moa1 and mouse MEIKIN, suggests that kinase coordination by a meiosis I regulator may be a general feature in the establishment of reductional chromosome segregation.
Collapse
Affiliation(s)
- Stefan Galander
- The Wellcome Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Rachael E Barton
- The Wellcome Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Weronika E Borek
- The Wellcome Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Christos Spanos
- The Wellcome Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - David A Kelly
- The Wellcome Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Daniel Robertson
- The Wellcome Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK
| | - Juri Rappsilber
- The Wellcome Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK; Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Adèle L Marston
- The Wellcome Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, Michael Swann Building, Max Born Crescent, Edinburgh EH9 3BF, UK.
| |
Collapse
|
17
|
Abstract
The origin of species would not have been possible without high fidelity DNA replication and complex genomes evolved with mechanisms that control the initiation of DNA replication at multiple origins on multiple chromosomes such that the genome is duplicated once and only once. The mechanisms that control the assembly and activation of the replicative helicase and the initiation of DNA replication in yeast and Xenopus egg extract systems have been identified and reviewed [1,2]. The goal of this review is to organize currently available data on the mechanisms that control the initiation of DNA replication in human cells.
Collapse
Affiliation(s)
- Tatiana N Moiseeva
- Department of Radiation Oncology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Christopher J Bakkenist
- Department of Radiation Oncology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| |
Collapse
|
18
|
Lowit A, Marchetti A, Corson S, Kuschmann A. Rhythmic performance in hypokinetic dysarthria: Relationship between reading, spontaneous speech and diadochokinetic tasks. J Commun Disord 2018; 72:26-39. [PMID: 29471176 PMCID: PMC5883324 DOI: 10.1016/j.jcomdis.2018.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 12/30/2017] [Accepted: 02/09/2018] [Indexed: 06/01/2023]
Abstract
•We investigated speech rhythm in people with Parkinson’s Disease (PwPD) and controls. •Even mildly affected PwPD differed from controls in their rhythmic performance. •PwPD showed less difference between reading and spontaneous speech. •Spontaneous speech highlighted more differences between speakers than reading. •DDK performance did not relate to rhythmic behaviour in connected speech.
Collapse
Affiliation(s)
- Anja Lowit
- School of Psychological Sciences and Health, Graham Hills Building, Strathclyde University, 40 George Street, Glasgow G1 1QE Scotland, United Kingdom.
| | - Agata Marchetti
- School of Psychological Sciences and Health, Strathclyde University, Psychological Sciences and Health, United Kingdom
| | - Stephen Corson
- Dept. of Mathematics and Statistics, Strathclyde University, United Kingdom
| | - Anja Kuschmann
- School of Psychological Sciences and Health, Strathclyde University, Psychological Sciences and Health, United Kingdom
| |
Collapse
|
19
|
Sclafani RA, Hesselberth JR. O Cdc7 kinase where art thou? Curr Genet 2018; 64:677-80. [PMID: 29134273 DOI: 10.1007/s00294-017-0782-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 11/07/2017] [Accepted: 11/09/2017] [Indexed: 10/18/2022]
Abstract
Although Cdc7 protein kinase is important for regulating DNA replication in all eukaryotes and is a target for cancer therapy, it has never been localized in cells. Recently, a novel molecular genomic method used by our laboratory to localize Cdc7 to regions of chromosomes. Originally, mutations in the CDC7 gene were found in the classic cdc mutant collection of Hartwell et al. (Genetics 74:267-286, 1973). The CDC7 gene was found to encode a protein kinase called DDK that has been studied for many years, establishing its precise role in the initiation of DNA replication at origins. Recently, clinical studies are underway with DDK inhibitors against DDK in cancer patients. However, the conundrum is that Cdc7 has never been detected at origins of replication even though many studies have suggested it should be there. We used "Calling Card" system in which DNA binding proteins are localized to the genome via retrotransposon insertion and deep-sequencing methods. We have shown that Cdc7 localizes at many regions of the genome and was enriched at functional origins of replication. These results are consistent with DDK's role in many additional genomic processes including mutagenesis, chromatid cohesion, and meiotic recombination. Thus, the main conclusion from our studies is that Cdc7 kinase is found at many locations in the genome, but is enriched at functional origins of replication. Furthermore, we propose that application of the Calling Card system to other eukaryotes should be useful in identification of functional origins in other eukaryotic cells.
Collapse
|
20
|
Tsubouchi H, Argunhan B, Tsubouchi T. Exiting prophase I: no clear boundary. Curr Genet 2018; 64:423-7. [PMID: 29071381 DOI: 10.1007/s00294-017-0771-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 10/17/2017] [Accepted: 10/20/2017] [Indexed: 12/18/2022]
Abstract
The meiotic cell cycle provides a unique model to study the relationship between recombinational DNA repair and the cell cycle, since homologous recombination, induced by programmed DNA double-strand breaks (DSBs), is integrated as an essential step during meiosis. The pachytene checkpoint, which is situated towards the end of meiotic prophase I, coordinates homologous recombination and cell cycle progression, similar to the DNA damage checkpoint mechanisms operating in vegetative cells. However, there are a number of features unique to meiosis, making the system optimized for the purpose of meiosis. Our recent work highlights the involvement of three major cell cycle kinases, Dbf4-dependent Cdc7 kinase, Polo kinase and CDK, in coordinating homologous recombination and the meiotic cell cycle. In this review, we will discuss the unique interplay between meiotic cell cycle control and homologous recombination during meiosis I.
Collapse
|
21
|
Collart C, Smith JC, Zegerman P. Chk1 Inhibition of the Replication Factor Drf1 Guarantees Cell-Cycle Elongation at the Xenopus laevis Mid-blastula Transition. Dev Cell 2017; 42:82-96.e3. [PMID: 28697335 DOI: 10.1016/j.devcel.2017.06.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 04/19/2017] [Accepted: 06/07/2017] [Indexed: 12/21/2022]
Abstract
The early cell divisions of many metazoan embryos are rapid and occur in the near absence of transcription. At the mid-blastula transition (MBT), the cell cycle elongates and several processes become established including the onset of bulk transcription and cell-cycle checkpoints. How these events are timed and coordinated is poorly understood. Here we show in Xenopus laevis that developmental activation of the checkpoint kinase Chk1 at the MBT results in the SCFβ-TRCP-dependent degradation of a limiting replication initiation factor Drf1. Inhibition of Drf1 is the primary mechanism by which Chk1 blocks cell-cycle progression in the early embryo and is an essential function of Chk1 at the blastula-to-gastrula stage of development. This study defines the downregulation of Drf1 as an important mechanism to coordinate the lengthening of the cell cycle and subsequent developmental processes. Activation of Chk1 at the Xenopus MBT results in the degradation of Drf1 Drf1 degradation is SCFβ-TRCP dependent Chk1 blocks the cell cycle in the early embryo through inhibition of Drf1 Inhibition of Drf1 is an essential function of Chk1 during gastrulation
Collapse
|
22
|
Seoane AI, Morgan DO. Firing of Replication Origins Frees Dbf4-Cdc7 to Target Eco1 for Destruction. Curr Biol 2017; 27:2849-2855.e2. [PMID: 28918948 DOI: 10.1016/j.cub.2017.07.070] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Revised: 07/12/2017] [Accepted: 07/31/2017] [Indexed: 12/14/2022]
Abstract
Robust progression through the cell-division cycle depends on the precisely ordered phosphorylation of hundreds of different proteins by cyclin-dependent kinases (CDKs) and other kinases. The order of CDK substrate phosphorylation depends on rising CDK activity, coupled with variations in substrate affinities for different CDK-cyclin complexes and the opposing phosphatases [1-4]. Here, we address the ordering of substrate phosphorylation by a second major cell-cycle kinase, Cdc7-Dbf4 or Dbf4-dependent kinase (DDK). The primary function of DDK is to initiate DNA replication by phosphorylating the Mcm2-7 replicative helicase [5-7]. DDK also phosphorylates the cohesin acetyltransferase Eco1 [8]. Sequential phosphorylations of Eco1 by CDK, DDK, and Mck1 create a phosphodegron that is recognized by the ubiquitin ligase SCFCdc4. DDK, despite being activated in early S phase, does not phosphorylate Eco1 to trigger its degradation until late S phase [8]. DDK associates with docking sites on loaded Mcm double hexamers at unfired replication origins [9, 10]. We hypothesized that these docking interactions sequester limiting amounts of DDK, delaying Eco1 phosphorylation by DDK until replication is complete. Consistent with this hypothesis, we find that overproduction of DDK leads to premature Eco1 degradation. Eco1 degradation also occurs prematurely if Mcm complex loading at origins is prevented by depletion of Cdc6, and Eco1 is stabilized if loaded Mcm complexes are prevented from firing by a Cdc45 mutant. We propose that the timing of Eco1 phosphorylation, and potentially that of other DDK substrates, is determined in part by sequestration of DDK at unfired replication origins during S phase.
Collapse
Affiliation(s)
- Agustin I Seoane
- Departments of Physiology and Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - David O Morgan
- Departments of Physiology and Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA.
| |
Collapse
|
23
|
Duncker BP. Mechanisms Governing DDK Regulation of the Initiation of DNA Replication. Genes (Basel) 2016; 8:genes8010003. [PMID: 28025497 PMCID: PMC5294998 DOI: 10.3390/genes8010003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/13/2016] [Accepted: 12/16/2016] [Indexed: 12/14/2022] Open
Abstract
The budding yeast Dbf4-dependent kinase (DDK) complex—comprised of cell division cycle (Cdc7) kinase and its regulatory subunit dumbbell former 4 (Dbf4)—is required to trigger the initiation of DNA replication through the phosphorylation of multiple minichromosome maintenance complex subunits 2-7 (Mcm2-7). DDK is also a target of the radiation sensitive 53 (Rad53) checkpoint kinase in response to replication stress. Numerous investigations have determined mechanistic details, including the regions of Mcm2, Mcm4, and Mcm6 phosphorylated by DDK, and a number of DDK docking sites. Similarly, the way in which the Rad53 forkhead-associated 1 (FHA1) domain binds to DDK—involving both canonical and non-canonical interactions—has been elucidated. Recent work has revealed mutual promotion of DDK and synthetic lethal with dpb11-1 3 (Sld3) roles. While DDK phosphorylation of Mcm2-7 subunits facilitates their interaction with Sld3 at origins, Sld3 in turn stimulates DDK phosphorylation of Mcm2. Details of a mutually antagonistic relationship between DDK and Rap1-interacting factor 1 (Rif1) have also recently come to light. While Rif1 is able to reverse DDK-mediated Mcm2-7 complex phosphorylation by targeting the protein phosphatase glycogen 7 (Glc7) to origins, there is evidence to suggest that DDK can counteract this activity by binding to and phosphorylating Rif1.
Collapse
Affiliation(s)
- Bernard P Duncker
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L3G1, Canada.
| |
Collapse
|
24
|
Bastia D, Srivastava P, Zaman S, Choudhury M, Mohanty BK, Bacal J, Langston LD, Pasero P, O'Donnell ME. Phosphorylation of CMG helicase and Tof1 is required for programmed fork arrest. Proc Natl Acad Sci U S A 2016; 113:E3639-48. [PMID: 27298353 DOI: 10.1073/pnas.1607552113] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Several important physiological transactions, including control of replicative life span (RLS), prevention of collision between replication and transcription, and cellular differentiation, require programmed replication fork arrest (PFA). However, a general mechanism of PFA has remained elusive. We previously showed that the Tof1-Csm3 fork protection complex is essential for PFA by antagonizing the Rrm3 helicase that displaces nonhistone protein barriers that impede fork progression. Here we show that mutations of Dbf4-dependent kinase (DDK) of Saccharomyces cerevisiae, but not other DNA replication factors, greatly reduced PFA at replication fork barriers in the spacer regions of the ribosomal DNA array. A key target of DDK is the mini chromosome maintenance (Mcm) 2-7 complex, which is known to require phosphorylation by DDK to form an active CMG [Cdc45 (cell division cycle gene 45), Mcm2-7, GINS (Go, Ichi, Ni, and San)] helicase. In vivo experiments showed that mutational inactivation of DDK caused release of Tof1 from the chromatin fractions. In vitro binding experiments confirmed that CMG and/or Mcm2-7 had to be phosphorylated for binding to phospho-Tof1-Csm3 but not to its dephosphorylated form. Suppressor mutations that bypass the requirement for Mcm2-7 phosphorylation by DDK restored PFA in the absence of the kinase. Retention of Tof1 in the chromatin fraction and PFA in vivo was promoted by the suppressor mcm5-bob1, which bypassed DDK requirement, indicating that under this condition a kinase other than DDK catalyzed the phosphorylation of Tof1. We propose that phosphorylation regulates the recruitment and retention of Tof1-Csm3 by the replisome and that this complex antagonizes the Rrm3 helicase, thereby promoting PFA, by preserving the integrity of the Fob1-Ter complex.
Collapse
|
25
|
Knockleby J, Kim BJ, Mehta A, Lee H. Cdk1-mediated phosphorylation of Cdc7 suppresses DNA re-replication. Cell Cycle 2016; 15:1494-505. [PMID: 27105124 PMCID: PMC4934051 DOI: 10.1080/15384101.2016.1176658] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 03/23/2016] [Accepted: 04/06/2016] [Indexed: 12/18/2022] Open
Abstract
To maintain genetic stability, the entire mammalian genome must replicate only once per cell cycle. This is largely achieved by strictly regulating the stepwise formation of the pre-replication complex (pre-RC), followed by the activation of individual origins of DNA replication by Cdc7/Dbf4 kinase. However, the mechanism how Cdc7 itself is regulated in the context of cell cycle progression is poorly understood. Here we report that Cdc7 is phosphorylated by a Cdk1-dependent manner during prometaphase on multiple sites, resulting in its dissociation from origins. In contrast, Dbf4 is not removed from origins in prometaphase, nor is it degraded as cells exit mitosis. Our data thus demonstrates that constitutive phosphorylation of Cdc7 at Cdk1 recognition sites, but not the regulation of Dbf4, prevents the initiation of DNA replication in normally cycling cells and under conditions that promote re-replication in G2/M. As cells exit mitosis, PP1α associates with and dephosphorylates Cdc7. Together, our data support a model where Cdc7 (de)phosphorylation is the molecular switch for the activation and inactivation of DNA replication in mitosis, directly connecting Cdc7 and PP1α/Cdk1 to the regulation of once-per-cell cycle DNA replication in mammalian cells.
Collapse
Affiliation(s)
- James Knockleby
- Tumour Biology Group, Advanced Medical Research Institute of Canada, Health Sciences North, Sudbury, Ontario, Canada
| | - Byung Ju Kim
- Tumour Biology Group, Advanced Medical Research Institute of Canada, Health Sciences North, Sudbury, Ontario, Canada
| | - Avani Mehta
- Tumour Biology Group, Advanced Medical Research Institute of Canada, Health Sciences North, Sudbury, Ontario, Canada
| | - Hoyun Lee
- Tumour Biology Group, Advanced Medical Research Institute of Canada, Health Sciences North, Sudbury, Ontario, Canada
- Departments of Medicine, the Faculty of Medicine, the University of Ottawa, Ottawa, Ontario, Canada
- Northern Ontario School of Medicine, Sudbury, Ontario, Canada
| |
Collapse
|
26
|
Deegan TD, Yeeles JT, Diffley JF. Phosphopeptide binding by Sld3 links Dbf4-dependent kinase to MCM replicative helicase activation. EMBO J 2016; 35:961-73. [PMID: 26912723 PMCID: PMC4864760 DOI: 10.15252/embj.201593552] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 02/02/2016] [Accepted: 02/03/2016] [Indexed: 12/17/2022] Open
Abstract
The initiation of eukaryotic DNA replication requires the assembly of active CMG (Cdc45-MCM-GINS) helicases at replication origins by a set of conserved and essential firing factors. This process is controlled during the cell cycle by cyclin-dependent kinase (CDK) and Dbf4-dependent kinase (DDK), and in response to DNA damage by the checkpoint kinase Rad53/Chk1. Here we show that Sld3, previously shown to be an essential CDK and Rad53 substrate, is recruited to the inactive MCM double hexamer in a DDK-dependent manner. Sld3 binds specifically to DDK-phosphorylated peptides from two MCM subunits (Mcm4, 6) and then recruits Cdc45. MCM mutants that cannot bind Sld3 or Sld3 mutants that cannot bind phospho-MCM or Cdc45 do not support replication. Moreover, phosphomimicking mutants in Mcm4 and Mcm6 bind Sld3 without DDK and facilitate DDK-independent replication. Thus, Sld3 is an essential "reader" of DDK phosphorylation, integrating signals from three distinct protein kinase pathways to coordinate DNA replication during S phase.
Collapse
Affiliation(s)
- Tom D Deegan
- The Francis Crick Institute, Clare Hall Laboratory, South Mimms Herts, UK
| | - Joseph Tp Yeeles
- The Francis Crick Institute, Clare Hall Laboratory, South Mimms Herts, UK
| | - John Fx Diffley
- The Francis Crick Institute, Clare Hall Laboratory, South Mimms Herts, UK
| |
Collapse
|
27
|
Abstract
Sexually reproducing organisms create gametes with half the somatic cell
chromosome number so that fusion of gametes at fertilization does not change the
ploidy of the cell. This reduction in chromosome number occurs by the
specialized cell division of meiosis in which two rounds of chromosome
segregation follow a single round of chromosome duplication. Meiotic crossovers
formed between the non-sister chromatids of homologous chromosomes, combined
with sister chromatid cohesion, physically connect homologs, thereby allowing
proper segregation at the first meiotic division. Meiotic recombination is
initiated by programmed double strand breaks (DSBs) whose repair is highly
regulated such that (1) there is a bias for recombination with homologs rather
than sister chromatids, (2) crossovers are distributed throughout the genome by
a process called interference, (3) crossover homeostasis regulates the balance
between crossover and non-crossover repair to maintain a critical number of
crossovers and (4) each pair of homologs receives at least one crossover. It was
previously known that the imposition of interhomolog bias in budding yeast
requires meiosis-specific modifications to the DNA damage response and the local
activation of the meiosis-specific Mek1/Mre4 (hereafter Mek1) kinase at DSBs.
However, because inactivation of Mek1 results in intersister, rather than
interhomolog DSB repair, whether Mek1 had a role in interhomolog pathway choice
was unknown. A recent study by Chen et al. (2015) reveals that
Mek1 indirectly regulates the crossover/non-crossover decision between homologs
as well as genetic interference. It does this by enabling phosphorylation of
Zip1, the meiosis-specific transverse filament protein of the synaptonemal
complex (SC), by the conserved cell cycle kinase, Cdc7-Dbf4 (DDK). These results
suggest that Mek1 is a “master regulator” of meiotic recombination in budding
yeast.
Collapse
Affiliation(s)
- Nancy M Hollingsworth
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215
| |
Collapse
|
28
|
Im JS, Park SY, Cho WH, Bae SH, Hurwitz J, Lee JK. RecQL4 is required for the association of Mcm10 and Ctf4 with replication origins in human cells. Cell Cycle 2015; 14:1001-9. [PMID: 25602958 DOI: 10.1080/15384101.2015.1007001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Though RecQL4 was shown to be essential for the initiation of DNA replication in mammalian cells, its role in initiation is poorly understood. Here, we show that RecQL4 is required for the origin binding of Mcm10 and Ctf4, and their physical interactions and association with replication origins are controlled by the concerted action of both CDK and DDK activities. Although RecQL4-dependent binding of Mcm10 and Ctf4 to chromatin can occur in the absence of pre-replicative complex, their association with replication origins requires the presence of the pre-replicative complex and CDK and DDK activities. Their association with replication origins and physical interactions are also targets of the DNA damage checkpoint pathways which prevent initiation of DNA replication at replication origins. Taken together, the RecQL4-dependent association of Mcm10 and Ctf4 with replication origins appears to be the first important step controlled by S phase promoting kinases and checkpoint pathways for the initiation of DNA replication in human cells.
Collapse
Affiliation(s)
- Jun-Sub Im
- a Department of Biology Education; Seoul National University ; Seoul , Korea
| | | | | | | | | | | |
Collapse
|
29
|
Xuan TD, Teschke R. Dihydro-5,6-dehydrokavain ( DDK) from Alpinia zerumbet: Its Isolation, Synthesis, and Characterization. Molecules 2015; 20:16306-19. [PMID: 26370954 DOI: 10.3390/molecules200916306] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 08/14/2015] [Accepted: 08/20/2015] [Indexed: 11/17/2022] Open
Abstract
Dihydro-5,6-dehydrokavain (DDK) is the major and most promising component of the tropical plant Alpinia zerumbet (shell ginger), a species of the ginger family Zingiberaceae. Alpinia zerumbet is known for its human use as a traditional herbal medicine, food, and dietary supplement. With its α-lactone ring, DDK belongs to the large chemical group of kavalactones, which are also found in kava (Piper methysticum), another herbal medicine; DDK is characterized by a double-bond linkage at positions 5,6 and the absence of a double-bond linkage at positions 7,8. This dissociates DDK from other kavalactones with their linkages at positions 7,8 and 5,6 that are both either completely saturated or unsaturated, or may have an unsaturated bond at the position 7,8 as well as a saturated bond at the position 5,6. DDK is easily identified and quantified by HPLC and GC. DDK contents in fresh leaves, stems and rhizomes range from 80 to 410 mg/g, requiring solvent extraction procedures to ensure high DDK yield. This is best achieved by hexane extraction from fresh rhizomes that were previously boiled in water, allowing DDK yields of up to 424 mg/g. Successful synthesis of DDK can be achieved by asymmetric pathways, whereas its simple chemical structure facilitates the synthesis of DDK derivatives by HCl hydrolysis. Thus, all synthesized products may be used for various commercial purposes, including the potential development of promising antiobesity pharmaceutical drugs, preparation of specific and safe dietary supplements, and use as effective natural herbicides or fungicides.
Collapse
|
30
|
Abstract
Cdc7 (cell division cycle 7) kinase together with its activation subunit ASK (also known as Dbf4) play pivotal roles in DNA replication and contribute also to other aspects of DNA metabolism such as DNA repair and recombination. While the biological significance of Cdc7 is widely appreciated, the molecular mechanisms through which Cdc7 kinase regulates these various DNA transactions remain largely obscure, including the role of Cdc7-ASK/Dbf4 under replication stress, a condition associated with diverse (patho)physiological scenarios. In this review, we first highlight the recent findings on a novel pathway that regulates the stability of the human Cdc7-ASK/Dbf4 complex under replication stress, its interplay with ATR-Chk1 signaling, and significance in the RAD18-dependent DNA damage bypass pathway. We also consider Cdc7 function in a broader context, considering both physiological conditions and pathologies associated with enhanced replication stress, particularly oncogenic transformation and tumorigenesis. Furthermore, we integrate the emerging evidence and propose a concept of Cdc7-ASK/Dbf4 contributing to genome integrity maintenance, through interplay with RAD18 that can serve as a molecular switch to dictate DNA repair pathway choice. Finally, we discuss the possibility of targeting Cdc7, particularly in the context of the Cdc7/RAD18-dependent translesion synthesis, as a potential innovative strategy for treatment of cancer.
Collapse
Affiliation(s)
- Masayuki Yamada
- Institute of Molecular and Translational Medicine; Faculty of Medicine and Dentistry; Palacky University; Olomouc, Czech Republic
| | - Hisao Masai
- Genome Dynamics Project; Department of Genome Medicine; Tokyo Metropolitan Institute of Medical Science; Tokyo, Japan
| | - Jiri Bartek
- Institute of Molecular and Translational Medicine; Faculty of Medicine and Dentistry; Palacky University; Olomouc, Czech Republic; Danish Cancer Society Research Center; Copenhagen, Denmark
| |
Collapse
|
31
|
Blitzblau HG, Hochwagen A. ATR/Mec1 prevents lethal meiotic recombination initiation on partially replicated chromosomes in budding yeast. eLife 2013; 2:e00844. [PMID: 24137535 PMCID: PMC3787542 DOI: 10.7554/elife.00844] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 08/22/2013] [Indexed: 12/02/2022] Open
Abstract
During gamete formation, crossover recombination must occur on replicated DNA to ensure proper chromosome segregation in the first meiotic division. We identified a Mec1/ATR- and Dbf4-dependent replication checkpoint in budding yeast that prevents the earliest stage of recombination, the programmed induction of DNA double-strand breaks (DSBs), when pre-meiotic DNA replication was delayed. The checkpoint acts through three complementary mechanisms: inhibition of Mer2 phosphorylation by Dbf4-dependent Cdc7 kinase, preclusion of chromosomal loading of Rec114 and Mre11, and lowered abundance of the Spo11 nuclease. Without this checkpoint, cells formed DSBs on partially replicated chromosomes. Importantly, such DSBs frequently failed to be repaired and impeded further DNA synthesis, leading to a rapid loss in cell viability. We conclude that a checkpoint-dependent constraint of DSB formation to duplicated DNA is critical not only for meiotic chromosome assortment, but also to protect genome integrity during gametogenesis. DOI:http://dx.doi.org/10.7554/eLife.00844.001 Most cells in an organism contain two sets of chromosomes, one inherited from the mother and the other from the father. However, sexual reproduction relies on the production of gametes—eggs and sperm—which contain only one set of chromosomes. These are produced through a specialized form of cell division called meiosis. Meiosis begins with a cell replicating its entire genome. Maternal and paternal versions of each chromosome then pair up and swap sections of their DNA through a process known as homologous recombination. This gives rise to chromosomes with new combinations of maternal and paternal genes. Finally, the cell undergoes two successive rounds of division—the first to produce a cell with two nuclei containing two sets of chromosomes each, and the second to produce four gametes, each containing a single set of chromosomes. Homologous recombination requires the formation of double-strand breaks in the DNA, but it is essential that these do not form before DNA replication is complete. Now, Blitzblau and Hochwagen have used yeast, which is easy to maintain in the lab and to manipulate genetically, to reveal the molecular components of a checkpoint that controls this process. Blitzblau and Hochwagen first used an inhibitor called hydroxyurea to block DNA replication in yeast cells, and confirmed that this treatment also suppressed the formation of double-strand breaks. By selectively inhibiting the activity of individual proteins, it was shown that break formation was controlled by a checkpoint that relies on two conserved proteins, the checkpoint kinase Mec1 (homologous to the human tumour suppressor ATR) and the cell-division kinase DDK. Moreover, when double-strand breaks were allowed to form on partially replicated chromosomes, DNA replication stalled and meiosis could not proceed normally, with lethal results for the yeast. These results explain how DNA replication and recombination are coordinated during meiosis in yeast. Moreover, because the genes that control meiosis are highly conserved from yeast to humans, they have implications for research into human fertility. DOI:http://dx.doi.org/10.7554/eLife.00844.002
Collapse
|
32
|
Cheng AN, Jiang SS, Fan CC, Lo YK, Kuo CY, Chen CH, Liu YL, Lee CC, Chen WS, Huang TS, Wang TY, Lee AYL. Increased Cdc7 expression is a marker of oral squamous cell carcinoma and overexpression of Cdc7 contributes to the resistance to DNA-damaging agents. Cancer Lett 2013; 337:218-25. [PMID: 23684929 DOI: 10.1016/j.canlet.2013.05.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 05/07/2013] [Accepted: 05/09/2013] [Indexed: 01/28/2023]
Abstract
Cdc7-Dbf4 kinase (Dbf4-dependent kinase, DDK) is an essential factor of DNA replication and DNA damage response (DDR), which is associated with tumorigenesis. However, Cdc7 expression has never been associated to the outcome of oral squamous cell carcinoma (OSCC) patients, and the mechanism underlying cancer cell survival mediated by Cdc7 remains unclear. The Cdc7 protein expression of 105 OSCC tumor and 30 benign tissues was examined by immunohistochemistry assay. Overall survival rates of 80 OSCC patients were measured using Kaplan-Meier estimates and the log-rank tests. Cdc7 overexpression by adenovirus system was used to scrutinize the underlying mechanism contributed to cancer cell survival upon DDR. In silico analysis showed that increased Cdc7 is a common feature of cancer. Cdc7 overexpression was found in 96 of 105 (91.4%) studied cases of OSCC patients. Patients with higher Cdc7 expression, either categorized into two groups: Cdc7 high expression (2+ to 3+) versus Cdc7 low expression (0 to 1+) [hazard ratios (HR)=2.6; 95% confidence interval (CI)=1.28-5.43; P=0.0087] or four groups (0 to 3+) [HR=1.71; 95% CI=1.20-2.44; P=0.0032], exhibited a poorer outcome. Multivariate analysis showed that Cdc7 is an independent marker for survival prediction. Overexpressed Cdc7 inhibits genotoxin-induced apoptosis to increase the survival of cancer cells. In summary, Cdc7 expression, which is universally upregulated in cancer, is an independent prognostic marker of OSCC. Cdc7 inhibits genotoxin-induced apoptosis and increases survival in cancer cells upon DDR, suggesting that high expression of Cdc7 enhances the resistance to chemotherapy.
Collapse
Affiliation(s)
- An Ning Cheng
- National Institute of Cancer Research, National Health Research Institutes, Zhunan, Miaoli, Taiwan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Abstract
Together with cyclin-dependent kinases, the Dbf4-dependent kinase (DDK) is essential to activate the Mcm2-7 helicase and, hence, initiate DNA replication in eukaryotes. Beyond its role as the regulatory subunit of the DDK complex, the Dbf4 protein also regulates the activity of other cell cycle kinases to mediate the checkpoint response and prevent premature mitotic exit under stress. Two features that are unusual in DNA replication proteins characterize Dbf4. The first is its evolutionary divergence; the second is how its conserved motifs are combined to form distinct functional units. This structural plasticity appears to be at odds with the conserved functions of Dbf4. In this review, we summarize recent genetic, biochemical and structural work delineating the multiple interactions mediated by Dbf4 and its various functions during the cell cycle. We also discuss how the limited sequence conservation of Dbf4 may be an advantage to regulate the activities of multiple cell cycle kinases.
Collapse
Affiliation(s)
- Lindsay A Matthews
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | | |
Collapse
|
34
|
Chen YC, Kenworthy J, Gabrielse C, Hänni C, Zegerman P, Weinreich M. DNA replication checkpoint signaling depends on a Rad53-Dbf4 N-terminal interaction in Saccharomyces cerevisiae. Genetics 2013; 194:389-401. [PMID: 23564203 DOI: 10.1534/genetics.113.149740] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Dbf4-dependent kinase (DDK) and cyclin-dependent kinase (CDK) are essential to initiate DNA replication at individual origins. During replication stress, the S-phase checkpoint inhibits the DDK- and CDK-dependent activation of late replication origins. Rad53 kinase is a central effector of the replication checkpoint and both binds to and phosphorylates Dbf4 to prevent late-origin firing. The molecular basis for the Rad53-Dbf4 physical interaction is not clear but occurs through the Dbf4 N terminus. Here we found that both Rad53 FHA1 and FHA2 domains, which specifically recognize phospho-threonine (pT), interacted with Dbf4 through an N-terminal sequence and an adjacent BRCT domain. Purified Rad53 FHA1 domain (but not FHA2) bound to a pT Dbf4 peptide in vitro, suggesting a possible phospho-threonine-dependent interaction between FHA1 and Dbf4. The Dbf4-Rad53 interaction is governed by multiple contacts that are separable from the Cdc5- and Msa1-binding sites in the Dbf4 N terminus. Importantly, abrogation of the Rad53-Dbf4 physical interaction blocked Dbf4 phosphorylation and allowed late-origin firing during replication checkpoint activation. This indicated that Rad53 must stably bind to Dbf4 to regulate its activity.
Collapse
|
35
|
Maturo S, Hill C, Bunting G, Ballif C, Maurer R, Hartnick C. Pediatric laryngeal diadochokinetic rates: establishing a normative database. Otolaryngol Head Neck Surg 2011; 146:302-6. [PMID: 22027868 DOI: 10.1177/0194599811426259] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Laryngeal diadochokinetic (L-DDK) rate is a measure of laryngeal neural integrity. The objectives for this study included the following: (1) establish the first comprehensive pediatric normative database for L-DDK rates (DDK) using the Voice Evaluation Suite, a computerized voice analysis program; and (2) analyze normal L-DDK rates for age and gender differences. STUDY DESIGN Cross-sectional study with planned data collection. SETTING Outpatient pediatric otolaryngology clinic. SUBJECTS AND METHODS Three hundred seven children aged 4 to 18 with normal voices. L-DDK rates were collected during a 6-month period. Main outcome measures included age, gender, and L-DDK rates. RESULTS Three hundred seven children (151 girls and 156 boys) were evaluated. There was no statistically significant difference between the overall mean L-DDK rate of boys (2.69 syllables/s) compared to girls (2.55 syllables/s; P > .05). Further analysis of all individual age groups did not reveal any statistical significance between boys and girls. There was a statistically significant difference among children aged 4 to 11 compared to those 12 to 18 years old. Among boys aged 4 to 11, the mean rate was 2.49 syllables per second, whereas among 12- to 18-year-olds, the rate was 2.95 syllables per second (P < .01). The mean rate was 2.40 syllables per second among girls aged 4 to 11 and 2.74 syllables per second for those aged 12 to 18 (P < .01). CONCLUSION This is the largest normative pediatric L-DDK analysis in the English literature. The findings suggest that neurolaryngeal development approaches adult maturation at the beginning of the teenage years. These data have the potential application for objective measurement of neurolaryngeal coordination in children with neurologic impairment and also in children who have undergone nerve reinnervation procedures.
Collapse
Affiliation(s)
- Steve Maturo
- Department of Otolaryngology Head and Neck Surgery, San Antonio Uniformed Services Health Education Consortium, Lackland AFB, Texas, USA
| | | | | | | | | | | |
Collapse
|