1
|
Zhou J, Zheng H, Zhang H, Yu W, Li B, Ye L, Wang L. MCM5 is a Novel Therapeutic Target for Glioblastoma. Onco Targets Ther 2024; 17:371-381. [PMID: 38765057 PMCID: PMC11100520 DOI: 10.2147/ott.s457600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Accepted: 05/08/2024] [Indexed: 05/21/2024] Open
Abstract
Objective MCM5 is a DNA licensing factor involved in cell proliferation and has been previously established as an excellent biomarker in a number of malignancies. Nevertheless, the role of MCM5 in GBM has not been fully clarified. The present study aimed to investigate the potential roles of MCM5 in the treatment of GBM and to elucidate its underlying mechanism, which is beneficial for developing new therapeutic strategies and predicting prognosis. Methods Firstly, we obtained transcriptomic and proteomic data from the TCGA and CPTAC databases on glioma patients. Employing the DeSeq2 R package, we then identified genes with joint differential expression in GBM tissues subjected to chemotherapy. To develop a prognostic risk score model, we performed univariate and multivariate Cox regression analyses. In vitro knockdown and overexpression of MCM5 were used to further investigate the biological functions of GBM cells. Additionally, we also delved into the upstream regulation of MCM5, revealing associations with several transcription factors. Finally, we investigated differences in immune cell infiltration and drug sensitivity across diverse risk groups identified in the prognostic risk model. Results In this study, the chemotherapy-treated GBM samples exhibited consistent alterations in 46 upregulated and 94 downregulated genes at both the mRNA and protein levels. Notably, MCM5 emerged as a gene with prognostic significance as well as potential therapeutic relevance. In vitro experiments subsequently validated the role of increased MCM5 expression in promoting GBM cell proliferation and resistance to TMZ. Correlations with transcription factors such as CREB1, CTCF, NFYB, NRF1, PBX1, TEAD1, and USF1 were discovered during upstream regulatory analysis, enriching our understanding of MCM5 regulatory mechanisms. The study additionally delves into immune cell infiltration and drug sensitivity, providing valuable insights for personalized treatment approaches. Conclusion This study identifies MCM5 as a key player in GBM, demonstrating its prognostic significance and potential therapeutic relevance by elucidating its role in promoting cell proliferation and resistance to chemotherapy.
Collapse
Affiliation(s)
- Jian Zhou
- Hyperbaric Oxygen Department, International Cancer Center, Shenzhen University General Hospital, Shenzhen University Medical School, Shenzhen, 518055, People’s Republic of China
- Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, National-Regional Key Technology Engineering Laboratory for Medical Ultrasound, School of Biomedical Engineering, Shenzhen University Medical School, Shenzhen, 518060, People’s Republic of China
| | - Housheng Zheng
- Hyperbaric Oxygen Department, International Cancer Center, Shenzhen University General Hospital, Shenzhen University Medical School, Shenzhen, 518055, People’s Republic of China
| | - Huiru Zhang
- Hyperbaric Oxygen Department, International Cancer Center, Shenzhen University General Hospital, Shenzhen University Medical School, Shenzhen, 518055, People’s Republic of China
| | - Wenqiang Yu
- Hyperbaric Oxygen Department, International Cancer Center, Shenzhen University General Hospital, Shenzhen University Medical School, Shenzhen, 518055, People’s Republic of China
| | - Baoer Li
- Hyperbaric Oxygen Department, International Cancer Center, Shenzhen University General Hospital, Shenzhen University Medical School, Shenzhen, 518055, People’s Republic of China
| | - Liang Ye
- Hyperbaric Oxygen Department, International Cancer Center, Shenzhen University General Hospital, Shenzhen University Medical School, Shenzhen, 518055, People’s Republic of China
| | - Lu Wang
- Hyperbaric Oxygen Department, International Cancer Center, Shenzhen University General Hospital, Shenzhen University Medical School, Shenzhen, 518055, People’s Republic of China
| |
Collapse
|
2
|
Sun G, Yu H, Wang P, Lopez-Guerrero M, Mural RV, Mizero ON, Grzybowski M, Song B, van Dijk K, Schachtman DP, Zhang C, Schnable JC. A role for heritable transcriptomic variation in maize adaptation to temperate environments. Genome Biol 2023; 24:55. [PMID: 36964601 PMCID: PMC10037803 DOI: 10.1186/s13059-023-02891-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 03/06/2023] [Indexed: 03/26/2023] Open
Abstract
Background Transcription bridges genetic information and phenotypes. Here, we evaluated how changes in transcriptional regulation enable maize (Zea mays), a crop originally domesticated in the tropics, to adapt to temperate environments. Result We generated 572 unique RNA-seq datasets from the roots of 340 maize genotypes. Genes involved in core processes such as cell division, chromosome organization and cytoskeleton organization showed lower heritability of gene expression, while genes involved in anti-oxidation activity exhibited higher expression heritability. An expression genome-wide association study (eGWAS) identified 19,602 expression quantitative trait loci (eQTLs) associated with the expression of 11,444 genes. A GWAS for alternative splicing identified 49,897 splicing QTLs (sQTLs) for 7614 genes. Genes harboring both cis-eQTLs and cis-sQTLs in linkage disequilibrium were disproportionately likely to encode transcription factors or were annotated as responding to one or more stresses. Independent component analysis of gene expression data identified loci regulating co-expression modules involved in oxidation reduction, response to water deprivation, plastid biogenesis, protein biogenesis, and plant-pathogen interaction. Several genes involved in cell proliferation, flower development, DNA replication, and gene silencing showed lower gene expression variation explained by genetic factors between temperate and tropical maize lines. A GWAS of 27 previously published phenotypes identified several candidate genes overlapping with genomic intervals showing signatures of selection during adaptation to temperate environments. Conclusion Our results illustrate how maize transcriptional regulatory networks enable changes in transcriptional regulation to adapt to temperate regions. Supplementary information The online version contains supplementary material available at 10.1186/s13059-023-02891-3.
Collapse
Affiliation(s)
- Guangchao Sun
- grid.24434.350000 0004 1937 0060Quantitative Life Sciences Initiative, University of Nebraska-Lincoln, Lincoln, USA
- grid.24434.350000 0004 1937 0060Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, USA
- grid.24434.350000 0004 1937 0060Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, USA
| | - Huihui Yu
- grid.24434.350000 0004 1937 0060Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, USA
- grid.24434.350000 0004 1937 0060School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, USA
| | - Peng Wang
- grid.24434.350000 0004 1937 0060Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, USA
| | - Martha Lopez-Guerrero
- grid.24434.350000 0004 1937 0060Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, USA
| | - Ravi V. Mural
- grid.24434.350000 0004 1937 0060Quantitative Life Sciences Initiative, University of Nebraska-Lincoln, Lincoln, USA
- grid.24434.350000 0004 1937 0060Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, USA
- grid.24434.350000 0004 1937 0060Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, USA
| | - Olivier N. Mizero
- grid.24434.350000 0004 1937 0060Quantitative Life Sciences Initiative, University of Nebraska-Lincoln, Lincoln, USA
- grid.24434.350000 0004 1937 0060Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, USA
- grid.24434.350000 0004 1937 0060Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, USA
| | - Marcin Grzybowski
- grid.24434.350000 0004 1937 0060Quantitative Life Sciences Initiative, University of Nebraska-Lincoln, Lincoln, USA
- grid.24434.350000 0004 1937 0060Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, USA
- grid.24434.350000 0004 1937 0060Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, USA
| | - Baoxing Song
- grid.5386.8000000041936877XInstitute for Genomic Diversity, Cornell University, Ithaca, USA
| | - Karin van Dijk
- grid.24434.350000 0004 1937 0060Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, USA
| | - Daniel P. Schachtman
- grid.24434.350000 0004 1937 0060Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, USA
- grid.24434.350000 0004 1937 0060Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, USA
| | - Chi Zhang
- grid.24434.350000 0004 1937 0060Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, USA
- grid.24434.350000 0004 1937 0060School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, USA
| | - James C. Schnable
- grid.24434.350000 0004 1937 0060Quantitative Life Sciences Initiative, University of Nebraska-Lincoln, Lincoln, USA
- grid.24434.350000 0004 1937 0060Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, USA
- grid.24434.350000 0004 1937 0060Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, USA
| |
Collapse
|
3
|
Poramba-Liyanage DW, Korthout T, Cucinotta CE, van Kruijsbergen I, van Welsem T, El Atmioui D, Ovaa H, Tsukiyama T, van Leeuwen F. Inhibition of transcription leads to rewiring of locus-specific chromatin proteomes. Genome Res 2020; 30:635-646. [PMID: 32188699 PMCID: PMC7197482 DOI: 10.1101/gr.256255.119] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 03/11/2020] [Indexed: 12/13/2022]
Abstract
Transcription of a chromatin template involves the concerted interaction of many different proteins and protein complexes. Analyses of specific factors showed that these interactions change during stress and upon developmental switches. However, how the binding of multiple factors at any given locus is coordinated has been technically challenging to investigate. Here we used Epi-Decoder in yeast to systematically decode, at one transcribed locus, the chromatin binding changes of hundreds of proteins in parallel upon perturbation of transcription. By taking advantage of improved Epi-Decoder libraries, we observed broad rewiring of local chromatin proteomes following chemical inhibition of RNA polymerase. Rapid reduction of RNA polymerase II binding was accompanied by reduced binding of many other core transcription proteins and gain of chromatin remodelers. In quiescent cells, where strong transcriptional repression is induced by physiological signals, eviction of the core transcriptional machinery was accompanied by the appearance of quiescent cell–specific repressors and rewiring of the interactions of protein-folding factors and metabolic enzymes. These results show that Epi-Decoder provides a powerful strategy for capturing the temporal binding dynamics of multiple chromatin proteins under varying conditions and cell states. The systematic and comprehensive delineation of dynamic local chromatin proteomes will greatly aid in uncovering protein–protein relationships and protein functions at the chromatin template.
Collapse
Affiliation(s)
| | - Tessy Korthout
- Division of Gene Regulation, Netherlands Cancer Institute, 1066CX Amsterdam, The Netherlands
| | - Christine E Cucinotta
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | - Ila van Kruijsbergen
- Division of Gene Regulation, Netherlands Cancer Institute, 1066CX Amsterdam, The Netherlands
| | - Tibor van Welsem
- Division of Gene Regulation, Netherlands Cancer Institute, 1066CX Amsterdam, The Netherlands
| | - Dris El Atmioui
- Leiden Institute for Chemical Immunology, Leiden University Medical Center, 2333ZC Leiden, The Netherlands.,Oncode Institute, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Huib Ovaa
- Leiden Institute for Chemical Immunology, Leiden University Medical Center, 2333ZC Leiden, The Netherlands.,Oncode Institute, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Toshio Tsukiyama
- Basic Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | - Fred van Leeuwen
- Division of Gene Regulation, Netherlands Cancer Institute, 1066CX Amsterdam, The Netherlands.,Department of Medical Biology, Amsterdam University Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| |
Collapse
|
4
|
Suzuki Y, Yamaguchi Y, Hanada H, Ishimi Y. Changes in MCM2-7 proteins at senescence. Genes Genet Syst 2019; 94:123-132. [PMID: 31092751 DOI: 10.1266/ggs.18-00062] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Cellular aging is characterized by the loss of DNA replication capability and is mainly brought about by various changes in chromatin structure. Here, we examined changes in MCM2-7 proteins, which act as a replicative DNA helicase, during aging of human WI38 fibroblasts at the single-cell level. We used nuclear accumulation of p21 as a marker of senescent cells, and examined changes in MCM2-7 by western blot analysis. First, we found that senescent cells are enriched for cells with a DNA content higher than 4N. Second, the levels of MCM2, MCM3, MCM4 and MCM6 proteins decreased in senescent cells. Third, cytoplasmic localization of MCM2 and MCM7 was observed in senescent cells, from an analysis of MCM2-7 except for MCM5. Consistent with this finding, fragmented MCM2 was predominant in these cells. These age-dependent changes in MCM2-7, a protein complex that directly affects cellular DNA replication, may play a critical role in cellular senescence.
Collapse
|
5
|
Abstract
Recently published structural and functional analyses of the CMG complex have provided insight into the mechanism of its DNA helicase function and into the distinct roles of its central six component proteins MCM2-MCM7 (MCM2-7). To activate CMG helicase, the two protein kinases CDK and DDK, as well as MCM10, are required. In addition to the initiation of DNA replication, MCM function must be regulated at the DNA replication steps of elongation and termination. Polyubiquitylation of MCM7 is involved in terminating MCM function. Reinitiation of DNA replication in a single cell cycle, which is prevented mainly by CDK, is understood at the molecular level. MCM2-7 gene expression is regulated during cellular aging and the cell cycle, and the expression depends on oxygen concentration. These regulatory processes have been described recently. Genomic structural alteration, which is an essential element in cancer progression, is mainly generated by disruptions of DNA replication fork structures. A point mutation in MCM4 that disturbs MCM2-7 function results in genomic instability, leading to the generation of cancer cells. In this review, I focus on the following points: 1) function of the MCM2-7 complex, 2) activation of MCM2-7 helicase, 3) regulation of MCM2-7 function, 4) MCM2-7 expression, and 5) the role of MCM mutation in cancer progression.
Collapse
|
6
|
Tsuji M, Tanaka T, Nagashima R, Sagisaka Y, Tousen Y, Nishide Y, Ishimi Y, Ishimi Y. Effect of daidzein and equol on DNA replication in MCF-7 cells. J Biochem 2018; 163:371-380. [PMID: 29346578 DOI: 10.1093/jb/mvy006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 10/30/2017] [Indexed: 11/13/2022] Open
Abstract
It has been reported that daidzein and equol stimulate DNA replication and proliferation of MCF-7 cells. However, their molecular mechanisms of action are still unclear. We examined the effects of daidzein and equol on DNA replication of MCF-7 cells, focusing on MCM2-7 proteins, which function as the replicative helicase. In the presence of either 1 μM of daidzein or equol, the number of cells in S-phase, which was determined by detecting bromodeoxyuridine incorporated into replicated DNA, almost doubled. The total amounts of MCM7 protein and chromatin-bound MCM7 protein increased in the presence of daidzein. The data suggest that phytoestrogens facilitate cell cycle progression in G1-phase by increasing the level of MCM proteins. In the presence of phytoestrogens, phosphorylation of Rb and levels of MCM2, 3 and 7 mRNA increased, suggesting that stimulation of MCM2-7 transcription is involved in the cell cycle progression. Under the same conditions, double-stranded DNA breakage in logarithmically growing MCF-7 cells, which was detected using anti-γ-H2AX antibodies, did not increase in the presence of equol.
Collapse
Affiliation(s)
- Mako Tsuji
- Ibaraki University, Mito, Ibaraki 310-8512, Japan
| | | | | | | | - Yuko Tousen
- National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo 162-8636, Japan
| | - Yoriko Nishide
- National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo 162-8636, Japan
| | - Yoshiko Ishimi
- National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo 162-8636, Japan
| | - Yukio Ishimi
- Ibaraki University, Mito, Ibaraki 310-8512, Japan
| |
Collapse
|
7
|
Carroll TD, Newton IP, Chen Y, Blow JJ, Näthke I. Lgr5 + intestinal stem cells reside in an unlicensed G 1 phase. J Cell Biol 2018; 217:1667-1685. [PMID: 29599208 PMCID: PMC5940300 DOI: 10.1083/jcb.201708023] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 01/23/2018] [Accepted: 02/27/2018] [Indexed: 12/21/2022] Open
Abstract
During late mitosis and the early G1 phase, the origins of replication are licensed by binding to double hexamers of MCM2-7. In this study, we investigated how licensing and proliferative commitment are coupled in the epithelium of the small intestine. We developed a method for identifying cells in intact tissue containing DNA-bound MCM2-7. Interphase cells above the transit-amplifying compartment had no DNA-bound MCM2-7, but still expressed the MCM2-7 protein, suggesting that licensing is inhibited immediately upon differentiation. Strikingly, we found most proliferative Lgr5+ stem cells are in an unlicensed state. This suggests that the elongated cell-cycle of intestinal stem cells is caused by an increased G1 length, characterized by dormant periods with unlicensed origins. Significantly, the unlicensed state is lost in Apc-mutant epithelium, which lacks a functional restriction point, causing licensing immediately upon G1 entry. We propose that the unlicensed G1 phase of intestinal stem cells creates a temporal window when proliferative fate decisions can be made.
Collapse
Affiliation(s)
- Thomas D Carroll
- Cell and Developmental Biology, University of Dundee, Dundee, Scotland, UK
| | - Ian P Newton
- Cell and Developmental Biology, University of Dundee, Dundee, Scotland, UK
| | - Yu Chen
- Cell and Developmental Biology, University of Dundee, Dundee, Scotland, UK
| | - J Julian Blow
- Centre for Gene Regulation and Expression, University of Dundee, Dundee, Scotland, UK
| | - Inke Näthke
- Cell and Developmental Biology, University of Dundee, Dundee, Scotland, UK
| |
Collapse
|
8
|
Cavelier P, Cau J, Morin N, Delsert C. Early gametogenesis in the Pacific oyster: new insights using stem cell and mitotic markers. ACTA ACUST UNITED AC 2017; 220:3988-3996. [PMID: 28860120 DOI: 10.1242/jeb.167734] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 08/28/2017] [Indexed: 01/08/2023]
Abstract
While our knowledge of bivalve gametogenesis has progressed in recent times, more molecular markers are needed in order to develop tissue imaging. Here, we identified stem cell and mitotic markers to further characterize oyster early gametogenesis, mainly through immunofluorescence microscopy. Intense alkaline phosphatase activity, a non-specific marker for stem cells, was detected on the outer edge of the gonad ducts at the post-spawning stage, suggesting an abundance of undifferentiated cells very early during the sexual cycle. This observation was confirmed using an antibody against Sox2, a transcription factor specific for stem or germline cells, which labeled cells in the gonad duct inner mass and ciliated epithelium early during the initial oyster sexual cycle. Moreover, Vasa, a cytoplasmic marker for germline cells, was also detected in the gonad acini and duct cells, thus confirming that germline cells were abundant early on. In addition, the binding of the minichromosome maintenance MCM6 protein to chromatin indicated the gonad acini and duct cells were engaged in the cell cycle. DNA replication was indeed confirmed by an abundant in vivo incorporation of BrdU into the duct cell chromatin. Finally, proliferation of acini and duct cells was demonstrated by the chromatin-bound Ser10-phosphorylated histone H3, a mitotic marker. The markers for the cell cycle and mitosis used here thus indicate that acini and duct cells were already actively dividing early during the oyster sexual cycle. In addition, together with the stem cell markers, these data reveal that the epithelium delimiting the duct outer edge contains a dynamic population of undifferentiated cells.
Collapse
Affiliation(s)
- Patricia Cavelier
- Université de Montpellier, 34095 Montpellier, France.,IGMM CNRS UMR 5535, 34293 Montpellier, France
| | - Julien Cau
- Université de Montpellier, 34095 Montpellier, France.,IGH CNRS UPR 1142, 34396 Montpellier, France
| | - Nathalie Morin
- Université de Montpellier, 34095 Montpellier, France.,CRBM CNRS UMR5237, 34293 Montpellier, France
| | - Claude Delsert
- Université de Montpellier, 34095 Montpellier, France .,CRBM CNRS UMR5237, 34293 Montpellier, France.,3AS Ifremer, 34250 Palavas-les-Flots, France
| |
Collapse
|
9
|
Li W, Cao F, Li J, Wang Z, Ren Y, Liang Z, Liu P. Simvastatin exerts anti-hepatitis B virus activity by inhibiting expression of minichromosome maintenance protein 7 in HepG2.2.15 cells. Mol Med Rep 2016; 14:5334-5342. [PMID: 27779671 DOI: 10.3892/mmr.2016.5868] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 09/30/2016] [Indexed: 11/06/2022] Open
Abstract
Simvastatin (SIM), a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, has been reported to inhibit the activity of hepatitis B virus (HBV), however, the mechanism underlying its antiviral function remains unknown. Minichromosome maintenance (MCM) 7, a component of the MCM complex, has been reported to act as an important host factor aiding virus genome replication in host cells. The present study demonstrated that downregulation of MCM7 inhibited the expression of proteins transferred by adenoviral vectors. This suggests an association between MCM7 and viral DNA expression. Thus, the current study aimed to investigate whether SIM affected MCM7 expression. Notably, the results of the present study indicated that following exposure to SIM the protein expression levels of MCM7 in HepG2.2.15, a human HBV‑transfected liver cell line, was decreased. In addition, the HBV DNA replication in the cell line was suppressed. As quantitative polymerase chain reaction experiments demonstrated that SIM did not downregulate the mRNA expression level of MCM7, the current study further investigated whether SIM affects the translation of MCM7. Western blot experiments indicated that SIM improved the activation of eukaryotic initiation factor‑2α (eIF2α), a protein synthesis initiation factor, and upregulated the upstream factors of eIF2α, protein kinase RNA‑like endoplasmic reticulum kinase, which is regulated by the liver kinase B1 (LKB1)‑AMP‑activated protein kinase (AMPK) signaling pathway. These results indicated that SIM induced HBV downregulation via an MCM‑dependent mechanism, and SIM may inhibit MCM7 expression by increasing the phosphorylation of eIF2α, which is mediated by the LKB1-AMPK signaling pathway.
Collapse
Affiliation(s)
- Wenjie Li
- Translational Medical Center, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Fei Cao
- Department of Oncology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710068, P.R. China
| | - Juan Li
- Translational Medical Center, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Zhixin Wang
- Department of Hepatobiliary Surgery, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Yu Ren
- Department of Surgical Oncology, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Zheyong Liang
- Translational Medical Center, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Peijun Liu
- Translational Medical Center, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| |
Collapse
|
10
|
Wu PYJ, Nurse P. Replication origin selection regulates the distribution of meiotic recombination. Mol Cell 2014; 53:655-62. [PMID: 24560273 PMCID: PMC3988929 DOI: 10.1016/j.molcel.2014.01.022] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 10/21/2013] [Accepted: 01/16/2014] [Indexed: 01/01/2023]
Abstract
The program of DNA replication, defined by the temporal and spatial pattern of origin activation, is altered during development and in cancers. However, whether changes in origin usage play a role in regulating specific biological processes remains unknown. We investigated the consequences of modifying origin selection on meiosis in fission yeast. Genome-wide changes in the replication program of premeiotic S phase do not affect meiotic progression, indicating that meiosis neither activates nor requires a particular origin pattern. In contrast, local changes in origin efficiencies between different replication programs lead to changes in Rad51 recombination factor binding and recombination frequencies in these domains. We observed similar results for Rad51 when changes in efficiencies were generated by directly targeting expression of the Cdc45 replication factor. We conclude that origin selection is a key determinant for organizing meiotic recombination, providing evidence that genome-wide modifications in replication program can modulate cellular physiology.
Collapse
Affiliation(s)
- Pei-Yun Jenny Wu
- Institute of Genetics and Development of Rennes, CNRS UMR 6290, 2 Avenue du Pr. Léon Bernard, 35043 Rennes, France; The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA.
| | - Paul Nurse
- The Rockefeller University, 1230 York Avenue, New York, NY 10021, USA; The Francis Crick Institute, 215 Euston Road, London NW12BE, UK
| |
Collapse
|
11
|
Taylor M, Moore K, Murray J, Aves SJ, Price C. Mcm10 interacts with Rad4/Cut5(TopBP1) and its association with origins of DNA replication is dependent on Rad4/Cut5(TopBP1). DNA Repair (Amst) 2011; 10:1154-63. [PMID: 21945095 DOI: 10.1016/j.dnarep.2011.09.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 08/31/2011] [Accepted: 09/01/2011] [Indexed: 12/31/2022]
Abstract
Initiation of DNA replication in eukaryotes is a highly conserved and ordered process involving the co-ordinated, stepwise association of distinct proteins at multiple origins of replication throughout the genome. Here, taking Schizosaccharomyces pombe as a model, the role of Rad4(TopBP1) in the assembly of the replication complex has been examined. Quantitative chromatin immunoprecipitation experiments confirm that Rad4(TopBP1) associates with origins of DNA replication and, in addition, demonstrate that the protein is not present within the active replisome. A direct interaction between Rad4(TopBP1) and Mcm10 is shown and this is reflected in the Rad4(TopBP1)-dependent origin association of Mcm10. Rad4(TopBP1) is also shown to interact with Sld2 and Sld3 and to be required for the stable origin association of these two proteins. Rad4(TopBP1) chromatin association at stalled replication forks was found to be dependent upon the checkpoint protein Rad9, which was not required for Rad4(TopBP1) origin association. Comparison of the levels of chromatin association at origins of replication and stalled replication forks and the differential requirement for Rad9 suggest functional differences for Rad4(TopBP1) at these distinct sites.
Collapse
Affiliation(s)
- Mark Taylor
- School of Health and Medicine, Division of Biomedical and Life Sciences, Biological Sciences Building, Lancaster University, Lancaster LA1 4YQ, UK
| | | | | | | | | |
Collapse
|
12
|
Sasaki T, Li A, Gillespie PJ, Blow JJ, Gilbert DM. Evidence for a mammalian late-G1 phase inhibitor of replication licensing distinct from geminin or Cdk activity. Nucleus 2011; 2:455-64. [PMID: 21983086 DOI: 10.4161/nucl.2.5.17859] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Pre-replication complexes (pre-RCs) are assembled onto DNA during late mitosis and G1 to license replication origins for use in S phase. In order to prevent re-replication of DNA, licensing must be completely shutdown prior to entry into S phase. While mechanisms preventing re-replication during S phase and mitosis have been elucidated, the means by which cells first prevent licensing during late G1 phase are poorly understood. We have employed a hybrid mammalian / Xenopus egg extract replication system to dissect activities that inhibit replication licensing at different stages of the cell cycle in Chinese Hamster Ovary (CHO) cells. We find that soluble extracts from mitotic cells inhibit licensing through a combination of geminin and Cdk activities, while extracts from S-phase cells inhibit licensing predominantly through geminin alone. Surprisingly however, geminin did not accumulate until after cells enter S phase. Unlike extracts from cells in early G1 phase, extracts from late G1 phase and early S phase cells contained an inhibitor of licensing that could not be accounted for by either geminin or Cdk. Moreover, inhibiting cyclin and geminin protein synthesis or inhibiting Cdk activity early in G1 phase did not prevent the appearance of inhibitory activity. These results suggest that a soluble inhibitor of replication licensing appears prior to entry into S phase that is distinct from either geminin or Cdk activity. Our hybrid system should permit the identification of this and other novel cell cycle regulatory activities.
Collapse
Affiliation(s)
- Takayo Sasaki
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | | | | | | | | |
Collapse
|
13
|
Ding L, Forsburg SL. Schizosaccharomyces pombe minichromosome maintenance-binding protein (MCM-BP) antagonizes MCM helicase. J Biol Chem 2011; 286:32918-30. [PMID: 21813639 DOI: 10.1074/jbc.m111.282541] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The minichromosome maintenance (MCM) complex, a replicative helicase, is a heterohexamer essential for DNA duplication and genome stability. We identified Schizosaccharomyces pombe mcb1(+) (Mcm-binding protein 1), an apparent orthologue of the human MCM-binding protein that associates with a subset of MCM complex proteins. mcb1(+) is an essential gene. Deletion of mcb1(+) caused cell cycle arrest after several generations with a cdc phenotype and disrupted nuclear structure. Mcb1 is an abundant protein, constitutively present across the cell cycle. It is widely distributed in cytoplasm and nucleoplasm and bound to chromatin. Co-immunoprecipitation suggested that Mcb1 interacts robustly with Mcm3-7 but not Mcm2. Overproduction of Mcb1 disrupted the association of Mcm2 with other MCM proteins, resulting in inhibition of DNA replication, DNA damage, and activation of the checkpoint kinase Chk1. Thus, Mcb1 appears to antagonize the function of MCM helicase.
Collapse
Affiliation(s)
- Lin Ding
- Molecular and Computational Biology Program, University of Southern California, Los Angeles, California 90089-2910, USA
| | | |
Collapse
|
14
|
Kanke M, Nishimura K, Kanemaki M, Kakimoto T, Takahashi TS, Nakagawa T, Masukata H. Auxin-inducible protein depletion system in fission yeast. BMC Cell Biol 2011; 12:8. [PMID: 21314938 PMCID: PMC3048574 DOI: 10.1186/1471-2121-12-8] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2010] [Accepted: 02/11/2011] [Indexed: 01/03/2023] Open
Abstract
Background Inducible inactivation of a protein is a powerful approach for analysis of its function within cells. Fission yeast is a useful model for studying the fundamental mechanisms such as chromosome maintenance and cell cycle. However, previously published strategies for protein-depletion are successful only for some proteins in some specific conditions and still do not achieve efficient depletion to cause acute phenotypes such as immediate cell cycle arrest. The aim of this work was to construct a useful and powerful protein-depletion system in Shizosaccaromyces pombe. Results We constructed an auxin-inducible degron (AID) system, which utilizes auxin-dependent poly-ubiquitination of Aux/IAA proteins by SCFTIR1 in plants, in fission yeast. Although expression of a plant F-box protein, TIR1, decreased Mcm4-aid, a component of the MCM complex essential for DNA replication tagged with Aux/IAA peptide, depletion did not result in an evident growth defect. We successfully improved degradation efficiency of Mcm4-aid by fusion of TIR1 with fission yeast Skp1, a conserved F-box-interacting component of SCF (improved-AID system; i-AID), and the cells showed severe defect in growth. The i-AID system induced degradation of Mcm4-aid in the chromatin-bound MCM complex as well as those in soluble fractions. The i-AID system in conjunction with transcription repression (off-AID system), we achieved more efficient depletion of other proteins including Pol1 and Cdc45, causing early S phase arrest. Conclusion Improvement of the AID system allowed us to construct conditional null mutants of S. pombe. We propose that the off-AID system is the powerful method for in vivo protein-depletion in fission yeast.
Collapse
Affiliation(s)
- Mai Kanke
- Graduate School of Science, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
| | | | | | | | | | | | | |
Collapse
|
15
|
Shultz RW, Lee TJ, Allen GC, Thompson WF, Hanley-Bowdoin L. Dynamic localization of the DNA replication proteins MCM5 and MCM7 in plants. PLANT PHYSIOLOGY 2009; 150:658-69. [PMID: 19357199 PMCID: PMC2689970 DOI: 10.1104/pp.109.136614] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Accepted: 04/02/2009] [Indexed: 05/21/2023]
Abstract
Genome integrity in eukaryotes depends on licensing mechanisms that prevent loading of the minichromosome maintenance complex (MCM2-7) onto replicated DNA during S phase. Although the principle of licensing appears to be conserved across all eukaryotes, the mechanisms that control it vary, and it is not clear how licensing is regulated in plants. In this work, we demonstrate that subunits of the MCM2-7 complex are coordinately expressed during Arabidopsis (Arabidopsis thaliana) development and are abundant in proliferating and endocycling tissues, indicative of a role in DNA replication. We show that endogenous MCM5 and MCM7 proteins are localized in the nucleus during G1, S, and G2 phases of the cell cycle and are released into the cytoplasmic compartment during mitosis. We also show that MCM5 and MCM7 are topologically constrained on DNA and that the MCM complex is stable under high-salt conditions. Our results are consistent with a conserved replicative helicase function for the MCM complex in plants but not with the idea that plants resemble budding yeast by actively exporting the MCM complex from the nucleus to prevent unauthorized origin licensing and rereplication during S phase. Instead, our data show that, like other higher eukaryotes, the MCM complex in plants remains in the nucleus throughout most of the cell cycle and is only dispersed in mitotic cells.
Collapse
Affiliation(s)
- Randall W Shultz
- Department of Molecular and Structural Biochemistry , North Carolina State University, Raleigh, North Carolina 27695-7651, USA.
| | | | | | | | | |
Collapse
|
16
|
Pai CC, García I, Wang SW, Cotterill S, Macneill SA, Kearsey SE. GINS inactivation phenotypes reveal two pathways for chromatin association of replicative alpha and epsilon DNA polymerases in fission yeast. Mol Biol Cell 2008; 20:1213-22. [PMID: 19109429 DOI: 10.1091/mbc.e08-04-0429] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The tetrameric GINS complex, consisting of Sld5-Psf1-Psf2-Psf3, plays an essential role in the initiation and elongation steps of eukaryotic DNA replication, although its biochemical function is unclear. Here we investigate the function of GINS in fission yeast, using fusion of Psf1 and Psf2 subunits to a steroid hormone-binding domain (HBD) to make GINS function conditional on the presence of beta-estradiol. We show that inactivation of Psf1-HBD causes a tight but rapidly reversible DNA replication arrest phenotype. Inactivation of Psf2-HBD similarly blocks premeiotic DNA replication and leads to loss of nuclear localization of another GINS subunit, Psf3. Inactivation of GINS has distinct effects on the replication origin association and chromatin binding of two of the replicative DNA polymerases. Inactivation of Psf1 leads to loss of chromatin binding of DNA polymerase epsilon, and Cdc45 is similarly affected. In contrast, chromatin association of the catalytic subunit of DNA polymerase alpha is not affected by defective GINS function. We suggest that GINS functions in a pathway that involves Cdc45 and is necessary for DNA polymerase epsilon chromatin binding, but that a separate pathway sets up the chromatin association of DNA polymerase alpha.
Collapse
Affiliation(s)
- Chen Chun Pai
- Department of Zoology, University of Oxford, Oxford OX1 3PS, United Kingdom
| | | | | | | | | | | |
Collapse
|
17
|
Current awareness on yeast. Yeast 2007. [DOI: 10.1002/yea.1326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|