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Yu N, Wu Y, Wei Q, Li X, Li M, Wu W. m 6A modification of CDC5L promotes lung adenocarcinoma progression through transcriptionally regulating WNT7B expression. Am J Cancer Res 2024; 14:3565-3583. [PMID: 39113868 PMCID: PMC11301290 DOI: 10.62347/qhfa9669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Accepted: 06/25/2024] [Indexed: 08/10/2024] Open
Abstract
Cell division cycle 5-like (CDC5L) protein is implicated in the development of various cancers. However, its role in the progression of lung adenocarcinoma (LUAD) remains uncertain. Our findings revealed frequent upregulation of CDC5L in LUAD, which correlated with poorer overall survival rates and advanced clinical stages. In vitro experiments demonstrated that CDC5L overexpression stimulated the proliferation, migration, and invasion of LUAD cells, whereas CDC5L knockdown exerted suppressive effects on these cellular processes. Furthermore, silencing CDC5L significantly inhibited tumor growth and metastasis in a xenograft mouse model. Mechanistically, CDC5L activates the Wnt/β-catenin signaling pathway by transcriptionally regulating WNT7B, thereby promoting LUAD progression. Besides, METTL14-mediated m6A modification contributed to CDC5L upregulation in an IGF2BP2-dependent manner. Collectively, our study uncovers a novel molecular mechanism by which the m6A-induced CDC5L functions as an oncogene in LUAD by activating the Wnt/β-catenin pathway through transcriptional regulation of WNT7B, suggesting that CDC5L may serve as a promising prognostic marker and therapeutic target for LUAD.
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Affiliation(s)
- Nanding Yu
- Department of Pulmonary and Critical Care Medicine, Fujian Medical University Union HospitalFuzhou 350001, Fujian, China
- Department of Geriatric Medicine, Fujian Medical University Union HospitalFuzhou 350001, Fujian, China
| | - Yingxiao Wu
- Department of Pulmonary and Critical Care Medicine, Fujian Medical University Union HospitalFuzhou 350001, Fujian, China
- Department of Geriatric Medicine, Fujian Medical University Union HospitalFuzhou 350001, Fujian, China
| | - Qiongying Wei
- Department of Pulmonary and Critical Care Medicine, Fujian Medical University Union HospitalFuzhou 350001, Fujian, China
- Department of Geriatric Medicine, Fujian Medical University Union HospitalFuzhou 350001, Fujian, China
| | - Xiaoping Li
- Department of Pulmonary and Critical Care Medicine, Fujian Medical University Union HospitalFuzhou 350001, Fujian, China
- Department of Geriatric Medicine, Fujian Medical University Union HospitalFuzhou 350001, Fujian, China
| | - Mengling Li
- Department of Pulmonary and Critical Care Medicine, Fujian Medical University Union HospitalFuzhou 350001, Fujian, China
- Department of Geriatric Medicine, Fujian Medical University Union HospitalFuzhou 350001, Fujian, China
| | - Weidong Wu
- Department of Thoracic Surgery, Fujian Medical University Union HospitalFuzhou 350001, Fujian, China
- Fujian Key Laboratory of Cardio-Thoracic Surgery, Fujian Medical UniversityFuzhou 350122, Fujian, China
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Chen G, Wei RS, Ma J, Li XH, Feng L, Yu JR. FOXA1 prolongs S phase and promotes cancer progression in non-small cell lung cancer through upregulation of CDC5L and activation of the ERK1/2 and JAK2 pathways. Kaohsiung J Med Sci 2023; 39:1077-1086. [PMID: 37658700 DOI: 10.1002/kjm2.12737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 05/25/2023] [Accepted: 07/06/2023] [Indexed: 09/03/2023] Open
Abstract
Non-small cell lung cancer (NSCLC) causes high mortality worldwide; however, its molecular pathways have not been fully investigated. The relationship between FOXA1 and CDC5L as well as their roles in NSCLC have not been comprehensively studied. Clinical tissues were collected from 78 NSCLC patients for clinical studies. The BEAS-2B human normal lung epithelial cell line and the A549, Calu-3, H526 and H2170 human NSCLC cell lines were used for in vitro studies. sh-FOXA1 and oe-CDC5L constructs were used to generate knockdown and overexpression models, respectively. The CCK-8 assay was used to analyze cell viability. The cell cycle and apoptosis were evaluated by flow cytometry analysis. The relationship between FOXA1 and CDC5L was demonstrated using dual-luciferase and ChIP assays. Gene levels were examined via immunohistochemistry, qRT-PCR and western blot analysis. FOXA1 levels were increased in NSCLC clinical tissues and cell lines. Depletion of FOXA1 increased the apoptosis rate and increased the proportion of cells in G2/M phase. In addition, we demonstrated that FOXA1 was directly bound to the promoter of CDC5L and that depletion of FOXA1 inhibited CDC5L expression. Overexpression of CDC5L induced ERK1/2 phosphorylation, induced JAK2 phosphorylation, inhibited cell apoptosis, prolonged S phase, and significantly reversed the effects of FOXA1 knockdown on the progression of NSCLC. The present study demonstrated that FOXA1 prolongs S phase and promotes NSCLC progression through upregulation of CDC5L and activation of the ERK1/2 and JAK2 pathways.
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Affiliation(s)
- Gang Chen
- Department of Thoracic Surgery, Shanxi Province Cancer Hospital/Shanxi Hospital Affiliated to Cancer Hospital, Chinese Academy of Medical Sciences/Cancer Hospital Affiliated to Shanxi Medical University, Taiyuan, Shanxi, People's Republic of China
| | - Rui-Shi Wei
- Department of Thoracic Surgery, Changzhou City Fourth People's Hospital/Changzhou Cancer Hospital, Changzhou, Jiangsu, People's Republic of China
| | - Jie Ma
- Department of Cardiothoracic Surgery, The Second Affiliated Hospital of Shanxi Medical University, Taiyuan, Shanxi, People's Republic of China
| | - Xin-Hua Li
- Department of Cardiothoracic Surgery, The Second Affiliated Hospital of Shanxi Medical University, Taiyuan, Shanxi, People's Republic of China
| | - Li Feng
- Department of Thoracic Surgery, Changzhou City Fourth People's Hospital/Changzhou Cancer Hospital, Changzhou, Jiangsu, People's Republic of China
| | - Jian-Rong Yu
- Department of Thoracic Surgery, Changzhou City Fourth People's Hospital/Changzhou Cancer Hospital, Changzhou, Jiangsu, People's Republic of China
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Long-read sequencing unveils high-resolution HPV integration and its oncogenic progression in cervical cancer. Nat Commun 2022; 13:2563. [PMID: 35538075 PMCID: PMC9091225 DOI: 10.1038/s41467-022-30190-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 04/19/2022] [Indexed: 01/03/2023] Open
Abstract
Integration of human papillomavirus (HPV) DNA into the human genome is considered as a key event in cervical carcinogenesis. Here, we perform comprehensive characterization of large-range virus-human integration events in 16 HPV16-positive cervical tumors using the Nanopore long-read sequencing technology. Four distinct integration types characterized by the integrated HPV DNA segments are identified with Type B being particularly notable as lacking E6/E7 genes. We further demonstrate that multiple clonal integration events are involved in the use of shared breakpoints, the induction of inter-chromosomal translocations and the formation of extrachromosomal circular virus-human hybrid structures. Combined with the corresponding RNA-seq data, we highlight LINC00290, LINC02500 and LENG9 as potential driver genes in cervical cancer. Finally, we reveal the spatial relationship of HPV integration and its various structural variations as well as their functional consequences in cervical cancer. These findings provide insight into HPV integration and its oncogenic progression in cervical cancer. The molecular mechanisms underlying cervical carcinogenesis following integration of HPV DNA into the human genome remain elusive. Here, the authors perform long-read sequencing in 16 HPV16-positive cervical tumors and identify distinct integration types, structural variations and potential driver genes.
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Crosstalk between Long Non Coding RNAs, microRNAs and DNA Damage Repair in Prostate Cancer: New Therapeutic Opportunities? Cancers (Basel) 2022; 14:cancers14030755. [PMID: 35159022 PMCID: PMC8834032 DOI: 10.3390/cancers14030755] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/20/2022] [Accepted: 01/21/2022] [Indexed: 02/04/2023] Open
Abstract
Simple Summary Non-coding RNAs are a type of genetic material that doesn’t make protein, but performs diverse regulatory functions. In prostate cancer, most treatments target proteins, and resistance to such therapies is common, leading to disease progression. Targeting non-coding RNAs may provide alterative treatment options and potentially overcome drug resistance. Major types of non-coding RNAs include tiny ‘microRNAs’ and much longer ‘long non-coding RNAs’. Scientific studies have shown that these form a major part of the human genome, and play key roles in altering gene activity and determining the fate of cells. Importantly, in cancer, their activity is altered. Recent evidence suggests that microRNAs and long non-coding RNAs play important roles in controlling response to DNA damage. In this review, we explore how different types of non-coding RNA interact to control cell DNA damage responses, and how this knowledge may be used to design better prostate cancer treatments and tests. Abstract It is increasingly appreciated that transcripts derived from non-coding parts of the human genome, such as long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), are key regulators of biological processes both in normal physiology and disease. Their dysregulation during tumourigenesis has attracted significant interest in their exploitation as novel cancer therapeutics. Prostate cancer (PCa), as one of the most diagnosed malignancies and a leading cause of cancer-related death in men, continues to pose a major public health problem. In particular, survival of men with metastatic disease is very poor. Defects in DNA damage response (DDR) pathways culminate in genomic instability in PCa, which is associated with aggressive disease and poor patient outcome. Treatment options for metastatic PCa remain limited. Thus, researchers are increasingly targeting ncRNAs and DDR pathways to develop new biomarkers and therapeutics for PCa. Increasing evidence points to a widespread and biologically-relevant regulatory network of interactions between lncRNAs and miRNAs, with implications for major biological and pathological processes. This review summarises the current state of knowledge surrounding the roles of the lncRNA:miRNA interactions in PCa DDR, and their emerging potential as predictive and diagnostic biomarkers. We also discuss their therapeutic promise for the clinical management of PCa.
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CDC5L promotes early chondrocyte differentiation and proliferation by modulating pre-mRNA splicing of SOX9, COL2A1, and WEE1. J Biol Chem 2021; 297:100994. [PMID: 34298017 PMCID: PMC8363834 DOI: 10.1016/j.jbc.2021.100994] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 07/12/2021] [Accepted: 07/19/2021] [Indexed: 11/23/2022] Open
Abstract
Ossification of the posterior longitudinal ligament (OPLL) of the spine is a common pathological condition that causes intractable myelopathy and radiculopathy, mainly the result of an endochondral ossification-like process. Our previous genome-wide association study identified six susceptibility loci for OPLL, including the cell division cycle 5-like (CDC5L) gene region. Here, we found CDC5L to be expressed in type II collagen-producing chondrocyte-like fibroblasts in human OPLL specimens, as well as in differentiating ATDC5 chondrocytes. Cdc5l siRNA transfection in murine chondrocytes decreased the expression of the early chondrogenic genes Sox9 and Col2a1, diminished the cartilage matrix production, and enhanced the expression of parathyroid-hormone-related protein (a resting chondrocyte marker). We also showed that Cdc5l shRNA suppressed the growth of cultured murine embryonal metatarsal cartilage rudiments and that Cdc5l knockdown suppressed the growth of ATDC5 cells. Fluorescence-activated cell sorting analysis revealed that the G2/M cell cycle transition was blocked; our data showed that Cdc5l siRNA transfection enhanced expression of Wee1, an inhibitor of the G2/M transition. Cdc5l siRNA also decreased the pre-mRNA splicing efficiency of Sox9 and Col2a1 genes in both ATDC5 cells and primary chondrocytes; conversely, loss of Cdc5l resulted in enhanced splicing of Wee1 pre-mRNA. Finally, an RNA-binding protein immunoprecipitation assay revealed that Cdc5l bound directly to these target gene transcripts. Overall, we conclude that Cdc5l promotes both early chondrogenesis and cartilage growth and may play a role in the etiology of OPLL, at least in part by fine-tuning the pre-mRNA splicing of chondrogenic genes and Wee1, thus initiating the endochondral ossification process.
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Weiss B, Allen GE, Kloehn J, Abid K, Jaquier-Gubler P, Curran JA. eIF4E3 forms an active eIF4F complex during stresses (eIF4FS) targeting mTOR and re-programs the translatome. Nucleic Acids Res 2021; 49:5159-5176. [PMID: 33893802 PMCID: PMC8136781 DOI: 10.1093/nar/gkab267] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/24/2021] [Accepted: 03/31/2021] [Indexed: 12/13/2022] Open
Abstract
The eIF4E are a family of initiation factors that bind the mRNA 5' cap, regulating the proteome and the cellular phenotype. eIF4E1 mediates global translation and its activity is controlled via the PI3K/AKT/mTOR pathway. mTOR down-regulation results in eIF4E1 sequestration into an inactive complex with the 4E binding proteins (4EBPs). The second member, eIF4E2, regulates the translatome during hypoxia. However, the exact function of the third member, eIF4E3, has remained elusive. We have dissected its function using a range of techniques. Starting from the observation that it does not interact with 4EBP1, we demonstrate that eIF4E3 recruitment into an eIF4F complex occurs when Torin1 inhibits the mTOR pathway. Ribo-seq studies demonstrate that this complex (eIF4FS) is translationally active during stress and that it selects specific mRNA populations based on 5' TL (UTR) length. The interactome reveals that it associates with cellular proteins beyond the cognate initiation factors, suggesting that it may have 'moon-lighting' functions. Finally, we provide evidence that cellular metabolism is altered in an eIF4E3 KO background but only upon Torin1 treatment. We propose that eIF4E3 acts as a second branch of the integrated stress response, re-programming the translatome to promote 'stress resistance' and adaptation.
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Affiliation(s)
- Benjamin Weiss
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Switzerland
| | - George Edward Allen
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Switzerland
| | - Joachim Kloehn
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Switzerland
| | - Karim Abid
- Catecholamine and Peptides Laboratory, Service of Clinical Pharmacology, Lausanne University Hospital and University of Lausanne, Switzerland
| | - Pascale Jaquier-Gubler
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Switzerland
| | - Joseph Alphonsus Curran
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Switzerland
- Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Switzerland
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Miserazzi A, Perrigault M, Sow M, Gelber C, Ciret P, Lomenech AM, Dalens JM, Weber C, Le Floch S, Lacroix C, Blanc P, Massabuau JC. Proteome changes in muscles, ganglia, and gills in Corbicula fluminea clams exposed to crude oil: Relationship with behavioural disturbances. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2020; 223:105482. [PMID: 32371337 DOI: 10.1016/j.aquatox.2020.105482] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 03/23/2020] [Accepted: 03/25/2020] [Indexed: 06/11/2023]
Abstract
The use of online remote control for 24/7 behavioural monitoring can play a key role in estimating the environmental status of aquatic ecosystems. Recording the valve activity of bivalve molluscs is a relevant approach in this context. However, a clear understanding of the underlying disturbances associated with behaviour is a key step. In this work, we studied freshwater Asian clams after exposure to crude oil (measured concentration, 167 ± 28 μg·L-1) for three days in a semi-natural environment using outdoor artificial streams. Three complementary approaches to assess and explore disturbances were used: behaviour by high frequency non-invasive (HFNI) valvometry, tissue contamination with polycyclic aromatic hydrocarbons (PAH), and proteomic analysis. Two tissues were targeted: the pool adductor muscles - retractor pedal muscle - cerebral and visceral ganglia, which is the effector of any valve movement and the gills, which are on the frontline during contamination. The behavioural response was marked by an increase in valve closure-duration, a decrease in valve opening-amplitude and an increase in valve agitation index during opening periods. There was no significant PAH accumulation in the muscle plus nervous ganglia pool, contrary to the situation in the gills, although the latter remained in the low range of data available in literature. Major proteomic changes included (i) a slowdown in metabolic and/or cellular processes in muscles plus ganglia pool associated with minor toxicological effect and (ii) an increase of metabolic and/or cellular processes in gills associated with a greater toxicological effect. The nature of the proteomic changes is discussed in terms of unequal PAH distribution and allows to propose a set of explanatory mechanisms to associate behaviour to underlying physiological changes following oil exposure. First, the first tissues facing contaminated water are the inhalant siphon, the mantle edge and the gills. The routine nervous activity in the visceral ganglia should be modified by nervous information originating from these tissues. Second, the nervous activity in the visceral ganglia could be modified by its own specific contamination. Third, a decrease in nervous activity of the cerebral ganglia close to the mouth, including some kind of narcosis, could contribute to a decrease in visceral ganglia activity via a decrease or blockage of the downward neuromodulation by the cerebro-visceral connective. This whole set of events can explain the decrease of metabolic activity in the adductor muscles, contribute to initiate the catch mechanism and then deeply modify the valve behaviour.
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Affiliation(s)
- A Miserazzi
- University of Bordeaux, EPOC, UMR 5805, Arcachon, France; CNRS, EPOC, UMR 5805, Talence, France
| | - M Perrigault
- University of Bordeaux, EPOC, UMR 5805, Arcachon, France; CNRS, EPOC, UMR 5805, Talence, France
| | - M Sow
- University of Bordeaux, EPOC, UMR 5805, Arcachon, France; CNRS, EPOC, UMR 5805, Talence, France
| | - C Gelber
- Pôles d'études et de Recherche de Lacq, TOTAL, Lacq, France
| | - P Ciret
- University of Bordeaux, EPOC, UMR 5805, Arcachon, France; CNRS, EPOC, UMR 5805, Talence, France
| | - A M Lomenech
- Center of Functional Genomics, Bordeaux University, Bordeaux, France
| | - J M Dalens
- Pôles d'études et de Recherche de Lacq, TOTAL, Lacq, France
| | - C Weber
- Pôles d'études et de Recherche de Lacq, TOTAL, Lacq, France
| | | | | | - P Blanc
- CSTJF, TOTAL SA, Pau, France
| | - J C Massabuau
- University of Bordeaux, EPOC, UMR 5805, Arcachon, France; CNRS, EPOC, UMR 5805, Talence, France.
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Zhang Z, Mao W, Wang L, Liu M, Zhang W, Wu Y, Zhang J, Mao S, Geng J, Yao X. Depletion of CDC5L inhibits bladder cancer tumorigenesis. J Cancer 2020; 11:353-363. [PMID: 31897231 PMCID: PMC6930429 DOI: 10.7150/jca.32850] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Accepted: 09/27/2019] [Indexed: 12/30/2022] Open
Abstract
Cell division cycle 5-like (CDC5L) protein is a cell cycle regulator of the G2/M transition and has been reported to participate in the catalytic step of pre-messenger RNA (mRNA) splicing and DNA damage repair. Recently, CDC5L was also found to act as a candidate oncogene in osteosarcoma and cervical tumours. However, the role of CDC5L expression in bladder cancer remains unclear. Here, we analysed the expression and clinical significance of CDC5L in bladder cancer tissues. The expression of CDC5L in fresh bladder cancer tissues and paraffin-embedded slices was evaluated by western blot and immunohistochemistry, respectively. We found that CDC5L was highly expressed in bladder cancer. The expression of CDC5L was significantly associated with bladder cancer pathology grade and Ki67 expression. Univariate and multivariate analyses showed that high CDC5L expression was an independent prognostic factor for the survival of bladder cancer patients. To determine whether CDC5L could regulate the proliferation of bladder cancer cells, we transfected bladder cancer cells with an interfering RNA targeting CDC5L and then investigated cell proliferation with a cell counting kit (CCK)-8, flow cytometry assays, colony formation and xenograft assay analyses. Our results indicate that knockdown of CDC5L inhibits proliferation of bladder cancer cells. In addition, reduced expression of CDC5L induced apoptosis of bladder cancer cells and inhibited their migration, invasion and EMT. These findings suggest that CDC5L might play an important role in bladder cancer and thus be a promising therapeutic target of bladder cancer.
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Affiliation(s)
- Ziwei Zhang
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, P. R. China
| | - Weipu Mao
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, P. R. China
| | - Longsheng Wang
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, P. R. China
| | - Mengnan Liu
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, P. R. China
| | - Wentao Zhang
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, P. R. China
| | - Yuan Wu
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, P. R. China
| | - Junfeng Zhang
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, P. R. China
| | - Shiyu Mao
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, P. R. China
| | - Jiang Geng
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, P. R. China
| | - Xudong Yao
- Department of Urology, Shanghai Tenth People's Hospital, Tongji University, Shanghai 200072, P. R. China
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Zhou L, Obhof T, Schneider K, Feldbrügge M, Nienhaus GU, Kämper J. Cytoplasmic Transport Machinery of the SPF27 Homologue Num1 in Ustilago maydis. Sci Rep 2018; 8:3611. [PMID: 29483520 PMCID: PMC5832149 DOI: 10.1038/s41598-018-21628-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 02/07/2018] [Indexed: 01/15/2023] Open
Abstract
In the phytopathogenic basidiomycete Ustilago maydis, the Num1 protein has a pivotal function in hyphal morphogenesis. Num1 functions as a core component of the spliceosome-associated Prp19/CDC5 complex (NTC). The interaction of Num1 with the kinesin motor Kin1 suggests a connection between a component of the splicing machinery and cytoplasmic trafficking processes. Previously it was shown that Num1 localizes predominantly in the nucleus; however, due to the diffraction-limited spatial resolution of conventional optical microscopy, it was not possible to attribute the localization to specific structures within the cytoplasm. We have now employed super-resolution localization microscopy to visualize Num1 in the cytoplasm by fusing it to a tandem dimeric Eos fluorescent protein (tdEosFP). The Num1 protein is localized within the cytoplasm with an enhanced density in the vicinity of microtubules. Num1 movement is found predominantly close to the nucleus. Movement is dependent on its interaction partner Kin1, but independent of Kin3. Our results provide strong evidence that, in addition to its involvement in splicing in the nucleus, Num1 has an additional functional role in the cytosol connected to the Kin1 motor protein.
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Affiliation(s)
- Lu Zhou
- Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.,Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Theresa Obhof
- Department of Genetics, Institute of Applied Biosciences, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Karina Schneider
- Department of Genetics, Institute of Applied Biosciences, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Michael Feldbrügge
- Institute of Microbiology, Cluster of Excellence on Plant Sciences, Heinrich-Heine-University, Düsseldorf, Germany
| | - G Ulrich Nienhaus
- Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany. .,Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany. .,Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, USA. .,Institute of Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen, Germany.
| | - Jörg Kämper
- Department of Genetics, Institute of Applied Biosciences, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
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Prp19 Arrests Cell Cycle via Cdc5L in Hepatocellular Carcinoma Cells. Int J Mol Sci 2017; 18:ijms18040778. [PMID: 28387715 PMCID: PMC5412362 DOI: 10.3390/ijms18040778] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 03/23/2017] [Accepted: 03/31/2017] [Indexed: 12/17/2022] Open
Abstract
Pre-mRNA processing factor 19 (Prp19) is involved in many cellular events including pre-mRNA processing and DNA damage response. Recently, it has been identified as a candidate oncogene in hepatocellular carcinoma (HCC). However, the role of Prp19 in tumor biology is still elusive. Here, we reported that Prp19 arrested cell cycle in HCC cells via regulating G2/M transition. Mechanistic insights revealed that silencing Prp19 inhibited the expression of cell division cycle 5-like (Cdc5L) via repressing the translation of Cdc5L mRNA and facilitating lysosome-mediated degradation of Cdc5L in HCC cells. Furthermore, we found that silencing Prp19 induced cell cycle arrest could be partially resumed by overexpressing Cdc5L. This work implied that Prp19 participated in mitotic progression and thus could be a promising therapeutic target of HCC.
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11
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Xu P, Chen H, Ying L, Cai W. AtDOF5.4/OBP4, a DOF Transcription Factor Gene that Negatively Regulates Cell Cycle Progression and Cell Expansion in Arabidopsis thaliana. Sci Rep 2016; 6:27705. [PMID: 27297966 PMCID: PMC4906354 DOI: 10.1038/srep27705] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 05/24/2016] [Indexed: 01/01/2023] Open
Abstract
In contrast to animals, plant development involves continuous organ formation, which requires strict regulation of cell proliferation. The core cell cycle machinery is conserved across plants and animals, but plants have developed new mechanisms that precisely regulate cell proliferation in response to internal and external stimuli. Here, we report that the DOF transcription factor OBP4 negatively regulates cell proliferation and expansion. OBP4 is a nuclear protein. Constitutive and inducible overexpression of OBP4 reduced the cell size and number, resulting in dwarf plants. Inducible overexpression of OBP4 in Arabidopsis also promoted early endocycle onset and inhibited cell expansion, while inducible overexpression of OBP4 fused to the VP16 activation domain in Arabidopsis delayed endocycle onset and promoted plant growth. Furthermore, gene expression analysis showed that cell cycle regulators and cell wall expansion factors were largely down-regulated in the OBP4 overexpression lines. Short-term inducible analysis coupled with in vivo ChIP assays indicated that OBP4 targets the CyclinB1;1, CDKB1;1 and XTH genes. These results strongly suggest that OBP4 is a negative regulator of cell cycle progression and cell growth. These findings increase our understanding of the transcriptional regulation of the cell cycle in plants.
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Affiliation(s)
- Peipei Xu
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Rd, Shanghai 200032, China
| | - Haiying Chen
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Rd, Shanghai 200032, China
| | - Lu Ying
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Rd, Shanghai 200032, China
| | - Weiming Cai
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Rd, Shanghai 200032, China
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12
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Evaluation of gene expression level of CDC5L and MACC1 in poor prognosis and progression of osteosarcoma. Tumour Biol 2015; 37:8153-7. [PMID: 26715275 DOI: 10.1007/s13277-015-4726-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Accepted: 12/21/2015] [Indexed: 12/30/2022] Open
Abstract
Current evidences have indicated that osteosarcoma is strongly associated with abnormal genetic and epigenetic changes that lead to the abnormal expression of oncogenes or methylation of tumor suppressor genes. In the present study, MACC1 and CDC5L mRNA levels in the patients with osteosarcoma were evaluated using quantitative real-time PCR. Our results demonstrated that CDC5L mRNA levels were higher in tumor tissues than in adjacent normal tissues (2.713 ± 0.738 vs. 1.071 ± 0.629; P < 0.05). Moreover, MACC1 was upregulated in tumor bone tissues than in adjacent normal tissues (3.221 ± 0. 624 vs. 1.427 ± 0.456; P < 0.05). Our result demonstrated that high expression of CDC5L was significantly related to advanced TNM stage (P = 0.032). No significant difference was determined between CDC5L mRNA expression and other clinicopathological parameters including age, gender, tumor diameter, location, tumor grade, and histological type. In addition, overexpression of MACC1 was strongly correlated with advanced TNM stage (P = 0.027) and high tumor grade (P = 0.035). Our findings indicated that mRNA level of CDC5L is correlated with advanced TNM stage, and MACC1 may be involved in progression of osteosarcoma.
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Expression of CDC5L is associated with tumor progression in gliomas. Tumour Biol 2015; 37:4093-103. [PMID: 26490980 DOI: 10.1007/s13277-015-4088-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 09/13/2015] [Indexed: 10/22/2022] Open
Abstract
Cell division cycle 5-like (CDC5L) protein is a cell cycle regulator of the G2/M transition and has been reported to participate in the catalytic step of pre-messenger RNA (mRNA) splicing and DNA damage repair. Recently, it was also found to act as a candidate oncogene in osteosarcoma and cervical tumors. However, the role of CDC5L expression in tumor biology was still unclear. Here, we analyzed the expression and clinical significance of CDC5L in gliomas. The expression of CDC5L in fresh glioma tissues and paraffin-embedded slices was evaluated by western blot and immunohistochemistry, respectively. We found that CDC5L was highly expressed in glioma tissues. The expression of CDC5L was significantly associated with glioma pathology grade and Ki-67 expression. Univariate and multivariate analyses showed that high CDC5L expression was an independent prognostic factor for glioma patients' survival. To determine whether CDC5L could regulate the proliferation of glioma cells, we transfected glioma cells with interfering RNA target CDC5L, then investigated cell proliferation with cell counting kit (CCK)-8, flow cytometry assays and colony formation analyses. Our results indicated that knockdown of CDC5L would inhibit proliferation of glioma cells. Besides, reduced expression of CDC5L could induce the apoptosis of glioma cells. These findings suggested that CDC5L might play an important role in glioma and thus be a promising therapeutic target of glioma.
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The Evolutionary History of R2R3-MYB Proteins Across 50 Eukaryotes: New Insights Into Subfamily Classification and Expansion. Sci Rep 2015; 5:11037. [PMID: 26047035 PMCID: PMC4603784 DOI: 10.1038/srep11037] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 04/28/2015] [Indexed: 01/21/2023] Open
Abstract
R2R3-MYB proteins (2R-MYBs) are one of the main transcription factor families in higher plants. Since the evolutionary history of this gene family across the eukaryotic kingdom remains unknown, we performed a comparative analysis of 2R-MYBs from 50 major eukaryotic lineages, with particular emphasis on land plants. A total of 1548 candidates were identified among diverse taxonomic groups, which allowed for an updated classification of 73 highly conserved subfamilies, including many newly identified subfamilies. Our results revealed that the protein architectures, intron patterns, and sequence characteristics were remarkably conserved in each subfamily. At least four subfamilies were derived from early land plants, 10 evolved from spermatophytes, and 19 from angiosperms, demonstrating the diversity and preferential expansion of this gene family in land plants. Moreover, we determined that their remarkable expansion was mainly attributed to whole genome and segmental duplication, where duplicates were preferentially retained within certain subfamilies that shared three homologous intron patterns (a, b, and c) even though up to 12 types of patterns existed. Through our integrated distributions, sequence characteristics, and phylogenetic tree analyses, we confirm that 2R-MYBs are old and postulate that 3R-MYBs may be evolutionarily derived from 2R-MYBs via intragenic domain duplication.
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Martin JW, Chilton-MacNeill S, Koti M, van Wijnen AJ, Squire JA, Zielenska M. Digital expression profiling identifies RUNX2, CDC5L, MDM2, RECQL4, and CDK4 as potential predictive biomarkers for neo-adjuvant chemotherapy response in paediatric osteosarcoma. PLoS One 2014; 9:e95843. [PMID: 24835790 PMCID: PMC4023931 DOI: 10.1371/journal.pone.0095843] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 03/31/2014] [Indexed: 12/04/2022] Open
Abstract
Osteosarcoma is the most common malignancy of bone, and occurs most frequently in children and adolescents. Currently, the most reliable technique for determining a patients’ prognosis is measurement of histopathologic tumor necrosis following pre-operative neo-adjuvant chemotherapy. Unfavourable prognosis is indicated by less than 90% estimated necrosis of the tumor. Neither genetic testing nor molecular biomarkers for diagnosis and prognosis have been described for osteosarcomas. We used the novel nanoString mRNA digital expression analysis system to analyse gene expression in 32 patients with sporadic paediatric osteosarcoma. This system used specific molecular barcodes to quantify expression of a set of 17 genes associated with osteosarcoma tumorigenesis. Five genes, from this panel, which encoded the bone differentiation regulator RUNX2, the cell cycle regulator CDC5L, the TP53 transcriptional inactivator MDM2, the DNA helicase RECQL4, and the cyclin-dependent kinase gene CDK4, were differentially expressed in tumors that responded poorly to neo-adjuvant chemotherapy. Analysis of the signalling relationships of these genes, as well as other expression markers of osteosarcoma, indicated that gene networks linked to RB1, TP53, PI3K, PTEN/Akt, myc and RECQL4 are associated with osteosarcoma. The discovery of these networks provides a basis for further experimental studies of role of the five genes (RUNX2, CDC5L, MDM2, RECQL4, and CDK4) in differential response to chemotherapy.
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Affiliation(s)
- Jeffrey W. Martin
- Department of Paediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Susan Chilton-MacNeill
- Department of Paediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Madhuri Koti
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - Andre J. van Wijnen
- Departments of Orthopedic Surgery and Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Jeremy A. Squire
- Department of Pathology and Molecular Medicine, Queen’s University, Kingston, Ontario, Canada
- Departments of Genetics and Pathology, Faculdade de Medicina de Ribeirão Preto - USP, Ribeirão Preto, São Paulo, Brazil
- * E-mail:
| | - Maria Zielenska
- Department of Paediatric Laboratory Medicine, Hospital for Sick Children, Toronto, Ontario, Canada
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Depletion of pre-mRNA splicing factor Cdc5L inhibits mitotic progression and triggers mitotic catastrophe. Cell Death Dis 2014; 5:e1151. [PMID: 24675469 PMCID: PMC3973201 DOI: 10.1038/cddis.2014.117] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 01/21/2014] [Accepted: 02/11/2014] [Indexed: 01/22/2023]
Abstract
Disturbing mitotic progression via targeted anti-mitotic therapy is an attractive strategy for cancer treatment. Therefore, the exploration and elucidation of molecular targets and pathways in mitosis are critical for the development of anti-mitotic drugs. Here, we show that cell division cycle 5-like (Cdc5L), a pre-mRNA splicing factor, is a regulator of mitotic progression. Depletion of Cdc5L causes dramatic mitotic arrest, chromosome misalignments and sustained activation of spindle assembly checkpoint, eventually leading to mitotic catastrophe. Moreover, these defects result from severe impairment of kinetochore-microtubule attachment and serious DNA damage. Genome-wide gene expression analysis reveals that Cdc5L modulates the expression of a set of genes involved in the mitosis and the DNA damage response. We further found that the pre-mRNA splicing efficiency of these genes were impaired when Cdc5L was knocked down. Interestingly, Cdc5L is highly expressed in cervical tumors and osteosarcoma. Finally, we demonstrate that downregulation of Cdc5L decreases the cell viability of related tumor cells. These results suggest that Cdc5L is a key regulator of mitotic progression and highlight the potential of Cdc5L as a target for cancer therapy.
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The SPF27 homologue Num1 connects splicing and kinesin 1-dependent cytoplasmic trafficking in Ustilago maydis. PLoS Genet 2014; 10:e1004046. [PMID: 24391515 PMCID: PMC3879195 DOI: 10.1371/journal.pgen.1004046] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 10/30/2013] [Indexed: 12/23/2022] Open
Abstract
The conserved NineTeen protein complex (NTC) is an integral subunit of the spliceosome and required for intron removal during pre-mRNA splicing. The complex associates with the spliceosome and participates in the regulation of conformational changes of core spliceosomal components, stabilizing RNA-RNA- as well as RNA-protein interactions. In addition, the NTC is involved in cell cycle checkpoint control, response to DNA damage, as well as formation and export of mRNP-particles. We have identified the Num1 protein as the homologue of SPF27, one of NTC core components, in the basidiomycetous fungus Ustilago maydis. Num1 is required for polarized growth of the fungal hyphae, and, in line with the described NTC functions, the num1 mutation affects the cell cycle and cell division. The num1 deletion influences splicing in U. maydis on a global scale, as RNA-Seq analysis revealed increased intron retention rates. Surprisingly, we identified in a screen for Num1 interacting proteins not only NTC core components as Prp19 and Cef1, but several proteins with putative functions during vesicle-mediated transport processes. Among others, Num1 interacts with the motor protein Kin1 in the cytoplasm. Similar phenotypes with respect to filamentous and polar growth, vacuolar morphology, as well as the motility of early endosomes corroborate the genetic interaction between Num1 and Kin1. Our data implicate a previously unidentified connection between a component of the splicing machinery and cytoplasmic transport processes. As the num1 deletion also affects cytoplasmic mRNA transport, the protein may constitute a novel functional interconnection between the two disparate processes of splicing and trafficking. In eukaryotic cells, nascent mRNA is processed by splicing to remove introns and to join the exon sequences. The processed mRNA is then transported out of the nucleus and employed by ribosomes to synthesize proteins. Splicing is achieved by the spliceosome and associated protein complexes, among them the so-called NineTeen complex (NTC). We have identified the Num1 protein as one of the core components of the NTC in the fungus Ustilago maydis, and could show that it is required for polarized growth of the filamentous fungal cells. Consistent with the NTC function, cells with a num1-deletion show reduced splicing of mRNA. Moreover, we uncover a novel cytoplasmic function of the Num1 protein: It physically interacts with the microtubule-associated Kinesin 1 motor protein, and phenotypic analyses corroborate that both proteins are functionally connected. Our findings reveal a yet unidentified role of a global splicing factor during intracellular trafficking processes. A possible connection between these disparate mechanisms presumably resides in mRNA-export out of the nucleus and/or the transport of mRNA within the cytoplasm.
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Gregory BL, Cheung VG. Natural variation in the histone demethylase, KDM4C, influences expression levels of specific genes including those that affect cell growth. Genome Res 2013; 24:52-63. [PMID: 24285722 PMCID: PMC3875861 DOI: 10.1101/gr.156141.113] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
DNA sequence variants influence gene expression and cellular phenotypes. In this study, we focused on natural variation in the gene encoding the histone demethylase, KDM4C, which promotes transcriptional activation by removing the repressive histone mark, H3K9me3, from its target genes. We uncovered cis-acting variants that contribute to extensive individual differences in KDM4C expression. We also identified the target genes of KDM4C and demonstrated that variation in KDM4C expression leads to differences in the growth of normal and some cancer cells. Together, our results from genetic mapping and molecular analysis provide an example of how genetic variation affects epigenetic regulation of gene expression and cellular phenotype.
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Affiliation(s)
- Brittany L Gregory
- VMD-PhD Program, University of Pennsylvania, School of Veterinary Medicine, Philadelphia, Pennsylvania 19104, USA
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Zhang S, Xie M, Ren G, Yu B. CDC5, a DNA binding protein, positively regulates posttranscriptional processing and/or transcription of primary microRNA transcripts. Proc Natl Acad Sci U S A 2013; 110:17588-93. [PMID: 24101471 PMCID: PMC3808604 DOI: 10.1073/pnas.1310644110] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
CDC5 is a MYB-related protein that exists in plants, animals, and fungi. In Arabidopsis, CDC5 regulates both growth and immunity through unknown mechanisms. Here, we show that CDC5 from Arabidopsis positively regulates the accumulation of microRNAs (miRNAs), which control many biological processes including development and adaptations to environments in plants. CDC5 interacts with both the promoters of genes encoding miRNAs (MIR) and the DNA-dependent RNA polymerase II. As a consequence, lack of CDC5 reduces the occupancy of polymerase II at MIR promoters, as well as MIR promoter activities. In addition, CDC5 is associated with the DICER-LIKE1 complex, which generates miRNAs from their primary transcripts and is required for efficient miRNA production. These results suggest that CDC5 may have dual roles in miRNA biogenesis: functioning as a positive transcription factor of MIR and/or acting as a component of the DICER-LIKE1 complex to enhance primary miRNA processing.
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Affiliation(s)
- Shuxin Zhang
- Center for Plant Science Innovation and School of Biological Sciences, University of Nebraska–Lincoln, Lincoln, NE 68588
| | - Meng Xie
- Center for Plant Science Innovation and School of Biological Sciences, University of Nebraska–Lincoln, Lincoln, NE 68588
| | - Guodong Ren
- Center for Plant Science Innovation and School of Biological Sciences, University of Nebraska–Lincoln, Lincoln, NE 68588
| | - Bin Yu
- Center for Plant Science Innovation and School of Biological Sciences, University of Nebraska–Lincoln, Lincoln, NE 68588
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Chen PH, Lee CI, Weng YT, Tarn WY, Tsao YP, Kuo PC, Hsu PH, Huang CW, Huang CS, Lee HH, Wu JT, Chen SL. BCAS2 is essential for Drosophila viability and functions in pre-mRNA splicing. RNA (NEW YORK, N.Y.) 2013; 19:208-218. [PMID: 23249746 PMCID: PMC3543084 DOI: 10.1261/rna.034835.112] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2012] [Accepted: 11/14/2012] [Indexed: 06/01/2023]
Abstract
Here, we show that dBCAS2 (CG4980, human Breast Carcinoma Amplified Sequence 2 ortholog) is essential for the viability of Drosophila melanogaster. We find that ubiquitous or tissue-specific depletion of dBCAS2 leads to larval lethality, wing deformities, impaired splicing, and apoptosis. More importantly, overexpression of hBCAS2 rescues these defects. Furthermore, the C-terminal coiled-coil domain of hBCAS2 binds directly to CDC5L and recruits hPrp19/PLRG1 to form a core complex for splicing in mammalian cells and can partially restore wing damage induced by knocking down dBCAS2 in flies. In summary, Drosophila and human BCAS2 share a similar function in RNA splicing, which affects cell viability.
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Affiliation(s)
- Po-Han Chen
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Chia-I Lee
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Yu-Tzu Weng
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Woan-Yuh Tarn
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Yeou-Ping Tsao
- Department of Ophthalmology, Mackay Memorial Hospital, Taipei 104, Taiwan
| | - Ping-Chang Kuo
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Pang-Hung Hsu
- Department of Life Science, College of Life Sciences, National Taiwan Ocean University, Keelung 202, Taiwan
- Institute of Bioscience and Biotechnology, College of Life Sciences, National Taiwan Ocean University, Keelung 202, Taiwan
| | - Chu-Wei Huang
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Chiun-Sheng Huang
- Department of Surgery, College of Medicine, National Taiwan University and Hospital, Taipei 100, Taiwan
| | - Hsiu-Hsiang Lee
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - June-Tai Wu
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei 100, Taiwan
- Department of Medical Research, National Taiwan University Hospital, Taipei 100, Taiwan
| | - Show-Li Chen
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 100, Taiwan
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Abstract
Osteosarcoma is a primary bone malignancy with a particularly high incidence rate in children and adolescents relative to other age groups. The etiology of this often aggressive cancer is currently unknown, because complicated structural and numeric genomic rearrangements in cancer cells preclude understanding of tumour development. In addition, few consistent genetic changes that may indicate effective molecular therapeutic targets have been reported. However, high-resolution techniques continue to improve knowledge of distinct areas of the genome that are more commonly associated with osteosarcomas. Copy number gains at chromosomes 1p, 1q, 6p, 8q, and 17p as well as copy number losses at chromosomes 3q, 6q, 9, 10, 13, 17p, and 18q have been detected by numerous groups, but definitive oncogenes or tumour suppressor genes remain elusive with respect to many loci. In this paper, we examine studies of the genetics of osteosarcoma to comprehensively describe the heterogeneity and complexity of this cancer.
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Zhang B, Shi Z, Duncan DT, Prodduturi N, Marnett LJ, Liebler DC. Relating protein adduction to gene expression changes: a systems approach. MOLECULAR BIOSYSTEMS 2011; 7:2118-27. [PMID: 21594272 DOI: 10.1039/c1mb05014a] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Modification of proteins by reactive electrophiles such as the 4-hydroxy-2-nonenal (HNE) plays a critical role in oxidant-associated human diseases. However, little is known about protein adduction and the mechanism by which protein damage elicits adaptive effects and toxicity. We developed a systems approach for relating protein adduction to gene expression changes through the integration of protein adduction, gene expression, protein-DNA interaction, and protein-protein interaction data. Using a random walk strategy, we expanded a list of responsive transcription factors inferred from gene expression studies to upstream signaling networks, which in turn allowed overlaying protein adduction data on the network for the prediction of stress sensors and their associated regulatory mechanisms. We demonstrated the general applicability of transcription factor-based signaling network inference using 103 known pathways. Applying our workflow on gene expression and protein adduction data from HNE-treatment not only rediscovered known mechanisms of electrophile stress but also generated novel hypotheses regarding protein damage sensors. Although developed for analyzing protein adduction data, the framework can be easily adapted for phosphoproteomics and other types of protein modification data.
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Affiliation(s)
- Bing Zhang
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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Inagaki S, Umeda M. Cell-Cycle Control and Plant Development. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2011; 291:227-61. [DOI: 10.1016/b978-0-12-386035-4.00007-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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24
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Bessonov S, Anokhina M, Krasauskas A, Golas MM, Sander B, Will CL, Urlaub H, Stark H, Lührmann R. Characterization of purified human Bact spliceosomal complexes reveals compositional and morphological changes during spliceosome activation and first step catalysis. RNA (NEW YORK, N.Y.) 2010; 16:2384-403. [PMID: 20980672 PMCID: PMC2995400 DOI: 10.1261/rna.2456210] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
To better understand the compositional and structural dynamics of the human spliceosome during its activation, we set out to isolate spliceosomal complexes formed after precatalytic B but prior to catalytically active C complexes. By shortening the polypyrimidine tract of the PM5 pre-mRNA, which lacks a 3' splice site and 3' exon, we stalled spliceosome assembly at the activation stage. We subsequently affinity purified human B(act) complexes under the same conditions previously used to isolate B and C complexes, and analyzed their protein composition by mass spectrometry. A comparison of the protein composition of these complexes allowed a fine dissection of compositional changes during the B to B(act) and B(act) to C transitions, and comparisons with the Saccharomyces cerevisiae B(act) complex revealed that the compositional dynamics of the spliceosome during activation are largely conserved between lower and higher eukaryotes. Human SF3b155 and CDC5L were shown to be phosphorylated specifically during the B to B(act) and B(act) to C transition, respectively, suggesting these modifications function at these stages of splicing. The two-dimensional structure of the human B(act) complex was determined by electron microscopy, and a comparison with the B complex revealed that the morphology of the human spliceosome changes significantly during its activation. The overall architecture of the human and S. cerevisiae B(act) complex is similar, suggesting that many of the higher order interactions among spliceosomal components, as well as their dynamics, are also largely conserved.
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Affiliation(s)
- Sergey Bessonov
- Department of Cellular Biochemistry, MPI of Biophysical Chemistry, D-37077 Göttingen, Germany
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25
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Walsh S, Pontén A, Fleischmann BK, Jovinge S. Cardiomyocyte cell cycle control and growth estimation in vivo--an analysis based on cardiomyocyte nuclei. Cardiovasc Res 2010; 86:365-73. [PMID: 20071355 DOI: 10.1093/cvr/cvq005] [Citation(s) in RCA: 225] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
AIMS Adult mammalian cardiomyocytes are traditionally viewed as being permanently withdrawn from the cell cycle. Whereas some groups have reported none, others have reported extensive mitosis in adult myocardium under steady-state conditions. Recently, a highly specific assay of 14C dating in humans has suggested a continuous generation of cardiomyocytes in the adult, albeit at a very low rate. Mice represent the most commonly used animal model for these studies, but their short lifespan makes them unsuitable for 14C studies. Herein, we investigate the cellular growth pattern for murine cardiomyocyte growth under steady-state conditions, addressed with new analytical and technical strategies, and we furthermore relate this to gene expression patterns. METHODS AND RESULTS The observed levels of DNA synthesis in early life were associated with cardiomyocyte proliferation. Mitosis was prolonged into early life, longer than the most conservative previous estimates. DNA synthesis in neonatal life was attributable to bi-nucleation, therefore suggesting that cardiomyocytes withdraw from the cell cycle shortly after birth. No cell cycle activity was observed in adult cardiomyocytes and significant polyploidy was observed in cardiomyocyte nuclei. CONCLUSION Gene analyses identified 32 genes whose expression was predicted to be particular to day 3-4 neonatal myocytes, compared with embryonic or adult cells. These cell cycle-associated genes are crucial to the understanding of the mechanisms of bi-nucleation and physiological cellular growth in the neonatal period.
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Affiliation(s)
- Stuart Walsh
- Lund Strategic Research Center for Stem Cell Biology and Cell Therapy, Lund University, Lund SE-22184, Sweden
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The homologue of Lentinula edodes ctg1, a target for CDC5 and its interacting partner CIPB, from Coprinopsis cinerea is involved in fruitingbody morphogenesis of C. cinerea. MYCOSCIENCE 2009. [DOI: 10.1007/s10267-009-0489-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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27
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Andersen DS, Tapon N. Drosophila MFAP1 is required for pre-mRNA processing and G2/M progression. J Biol Chem 2008; 283:31256-67. [PMID: 18765666 DOI: 10.1074/jbc.m803512200] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The mammalian spliceosome has mainly been studied using proteomics. The isolation and comparison of different splicing intermediates has revealed the dynamic association of more than 200 splicing factors with the spliceosome, relatively few of which have been studied in detail. Here, we report the characterization of the Drosophila homologue of microfibril-associated protein 1 (dMFAP1), a previously uncharacterized protein found in some human spliceosomal fractions ( Jurica, M. S., and Moore, M. J. (2003) Mol. Cell 12, 5-14 ). We show that dMFAP1 binds directly to the Drosophila homologue of Prp38p (dPrp38), a tri-small nuclear ribonucleoprotein component ( Xie, J., Beickman, K., Otte, E., and Rymond, B. C. (1998) EMBO J. 17, 2938-2946 ), and is required for pre-mRNA processing. dMFAP1, like dPrp38, is essential for viability, and our in vivo data show that cells with reduced levels of dMFAP1 or dPrp38 proliferate more slowly than normal cells and undergo apoptosis. Consistent with this, double-stranded RNA-mediated depletion of dPrp38 or dMFAP1 causes cells to arrest in G(2)/M, and this is paralleled by a reduction in mRNA levels of the mitotic phosphatase string/cdc25. Interestingly double-stranded RNA-mediated depletion of a wide range of core splicing factors elicits a similar phenotype, suggesting that the observed G(2)/M arrest might be a general consequence of interfering with spliceosome function.
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Affiliation(s)
- Ditte S Andersen
- Cancer Research UK, London Research Institute, London WC2A 3PX, UK
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28
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Lu XY, Lu Y, Zhao YJ, Jaeweon K, Kang J, Xiao-Nan L, Ge G, Meyer R, Perlaky L, Hicks J, Chintagumpala M, Cai WW, Ladanyi M, Gorlick R, Lau CC, Pati D, Sheldon M, Rao PH. Cell cycle regulator gene CDC5L, a potential target for 6p12-p21 amplicon in osteosarcoma. Mol Cancer Res 2008; 6:937-46. [PMID: 18567798 DOI: 10.1158/1541-7786.mcr-07-2115] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Osteosarcoma is a primary malignant tumor of bone arising from primitive bone-forming mesenchymal cells and accounts for approximately 60% of malignant bone tumors. Our comparative genomic hybridization (CGH) studies have identified frequent amplification at 6p12-p21, 12q13-q15, and 17p11.2 in osteosarcoma. Of these amplified regions, 6p12-p21 is particularly interesting because of its association with progression and poor prognosis in patients with osteosarcoma. In an attempt to identify aberrantly expressed gene(s) mapping to the 6p12-p21 amplicon, a region-specific array was generated using 108 overlapping BAC and P1 clones covering a 28.8-Mb region at 0.26-Mb intervals. Based on array CGH analysis, the 6p amplicon was refined to 7.9 Mb between the clones RP11-91E11 and RP1-244F2 and 10 amplified clones, with possible target genes, were identified. To study the expression pattern of the target genes from the hotspot amplicon and known candidate genes from 6p12-21, we did quantitative reverse transcription-PCR analysis of MAPK14, MAPK13, CDKN1A, PIM1, MDGA1, BTB9, DNAH8, CCND3, PTK7, CDC5L, and RUNX2 on osteosarcoma patient samples and seven cell lines. The combined array CGH and quantitative reverse transcription-PCR analysis identified amplification and overexpression of CDC5L, CCND3, and RUNX2. We screened these three genes for protein expression by Western blotting and immunohistochemistry and detected overexpression of CDC5L. Furthermore, we used an in vivo assay to show that CDC5L possesses potential oncogenic activity. These results indicate that CDC5L, a cell cycle regulator important for the G2-M transition, is the most likely candidate oncogene for the 6p12-p21 amplicon found in osteosarcoma.
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Affiliation(s)
- Xin-Yan Lu
- Texas Children's Cancer Center, Baylor College of Medicine, 6621 Fannin Street, MC 3-3320, Houston, TX 77030, USA
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Gräub R, Lancero H, Pedersen A, Chu M, Padmanabhan K, Xu XQ, Spitz P, Chalkley R, Burlingame AL, Stokoe D, Bernstein HS. Cell cycle-dependent phosphorylation of human CDC5 regulates RNA processing. Cell Cycle 2008; 7:1795-803. [PMID: 18583928 DOI: 10.4161/cc.7.12.6017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
CDC5 proteins are components of the pre-mRNA splicing complex and essential for cell cycle progression in yeast, plants and mammals. Human CDC5 is phosphorylated in a mitogen-dependent manner, and its association with the spliceosome is ATP-dependent. Examination of the amino acid sequence suggests that CDC5L may be phosphorylated at up to 28 potential consensus recognition sequences for known kinases, however, the identity of actual phosphorylation sites, their role in regulating CDC5L activity, and the kinases responsible for their phosphorylation have not previously been determined. Using two-dimensional phosphopeptide mapping and nanoelectrospray mass spectrometry, we now show that CDC5L is phosphorylated on at least nine sites in vivo. We demonstrate that while CDC5L is capable of forming homodimers in vitro and in vivo, neither homodimerization nor nuclear localization is dependent on phosphorylation at these sites. Using an in vitro splicing assay, we show that phosphorylation of CDC5L at threonines 411 and 438 within recognition sequences for CDKs are required for CDC5L-mediated pre-mRNA splicing. We also demonstrate that a specific inhibitor of CDK2, CVT-313, inhibits CDC5L phosphorylation in both in vitro kinase assays and in vivo radiolabeling experiments in cycling cells. These studies represent the first demonstration of a regulatory role for phosphorylation of CDC5L, and suggest that targeting these sites or the implicated kinases may provide novel strategies for treating disorders of unguarded cellular proliferation, such as cancer.
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Affiliation(s)
- Remo Gräub
- Cardiovascular Research Institute, University of California, San Francisco, CA 94143-0130, USA
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Nakazawa T, Kaneko S, Miyazaki Y, Jojima T, Yamazaki T, Katsukawa S, Shishido K. Basidiomycete Lentinula edodes CDC5 and a novel interacting protein CIPB bind to a newly isolated target gene in an unusual manner. Fungal Genet Biol 2008; 45:818-28. [DOI: 10.1016/j.fgb.2008.02.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Revised: 02/25/2008] [Accepted: 02/25/2008] [Indexed: 11/27/2022]
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Lin Z, Yin K, Zhu D, Chen Z, Gu H, Qu LJ. AtCDC5 regulates the G2 to M transition of the cell cycle and is critical for the function of Arabidopsis shoot apical meristem. Cell Res 2008; 17:815-28. [PMID: 17768399 DOI: 10.1038/cr.2007.71] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
As a cell cycle regulator, the Myb-related CDC5 protein was reported to be essential for the G2 phase of the cell cycle in yeast and animals, but little is known about its function in plants. Here we report the functional characterization of the CDC5 gene in Arabidopsis thaliana. Arabidopsis CDC5 (AtCDC5) is mainly expressed in tissues with high cell division activity, and is expressed throughout the entire process of embryo formation. The AtCDC5 loss-of-function mutant is embryonic lethal. In order to investigate the function of AtCDC5 in vivo, we generated AtCDC5-RNAi plants in which the expression of AtCDC5 was reduced by RNA interference. We found that the G2 to M (G2/M) phase transition was affected in the AtCDC5-RNAi plants, and that endoreduplication was increased. Additionally, the maintenance of shoot apical meristem (SAM) function was disturbed in the AtCDC5-RNAi plants, in which both the WUSCHEL (WUS)-CLAVATA (CLV) and the SHOOT MERISTEMLESS (STM) pathways were impaired. In situ hybridization analysis showed that the expression of STM was greatly reduced in the shoot apical cells of the AtCDC5-RNAi plants. Moreover, cyclinB1 or Histone4 was found to be expressed in some of these cells when the transcript of STM was undetectable. These results suggest that AtCDC5 is essential for the G2/M phase transition and may regulate the function of SAM by controlling the expression of STM and WUS.
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Affiliation(s)
- Zhiqiang Lin
- National Laboratory for Protein Engineering and Plant Genetic Engineering, Peking-Yale Joint Research Center for Plant Molecular Genetics and AgroBiotechnology, College of Life Sciences, Peking University, Beijing, China
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Dixon DN, Izon DJ, Dagger S, Callow MJ, Taplin RH, Kees UR, Greene WK. TLX1/HOX11 transcription factor inhibits differentiation and promotes a non-haemopoietic phenotype in murine bone marrow cells. Br J Haematol 2007; 138:54-67. [PMID: 17555447 DOI: 10.1111/j.1365-2141.2007.06626.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The TLX/HOX11 subfamily of divergent homeobox genes are involved in various aspects of embryogenesis and, in the case of TLX1/HOX11 and TLX3/HOX11L2, feature prominently as oncogenes in human T-cell acute lymphoblastic leukaemia. TLX1 possesses immortalising activity in a wide variety of blood cell lineages, however, the effect of this oncogene on haemopoietic cell differentiation has not been fully investigated. We therefore constitutively expressed TLX1 in murine bone marrow or fetal liver cells using retroviral transfer followed by transplantation and/or in vitro culture. TLX1 was found to dramatically alter haemopoiesis, promoting the emergence of a non-haemopoietic CD45(-) CD31(+) cell population while markedly inhibiting erythroid and granulocytic cell differentiation. To identify genetic programs perturbed by TLX1, a comparison of transcript profiles from J2E erythroid cells with and without enforced TLX1 expression was undertaken. This revealed a pattern of gene expression indicative of enhanced proliferation coupled to differentiation arrest. Of the genes identified, two, KIT and VEGFC, were found to be potential TLX1 targets based on transcriptional assays. These results demonstrate that TLX1 can act broadly to impair haemopoiesis and divert differentiation to an alternative fate. This may account for its ability to promote the pre-leukaemic state via perturbation of specific gene expression programs.
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Affiliation(s)
- Darcelle N Dixon
- School of Veterinary and Biomedical Sciences, Division of Health Sciences, Murdoch University, Murdoch, Western Australia, Australia
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Bicknell KA, Coxon CH, Brooks G. Can the cardiomyocyte cell cycle be reprogrammed? J Mol Cell Cardiol 2007; 42:706-21. [PMID: 17362983 DOI: 10.1016/j.yjmcc.2007.01.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2006] [Revised: 01/02/2007] [Accepted: 01/16/2007] [Indexed: 10/23/2022]
Abstract
Cardiac repair following myocardial injury is restricted due to the limited proliferative potential of adult cardiomyocytes. The ability of mammalian cardiomyocytes to proliferate is lost shortly after birth as cardiomyocytes withdraw from the cell cycle and differentiate. We do not fully understand the molecular and cellular mechanisms that regulate this cell cycle withdrawal, although if we could it might lead to the discovery of novel therapeutic targets for improving cardiac repair following myocardial injury. For the last decade, researchers have investigated cardiomyocyte cell cycle control, commonly using transgenic mouse models or recombinant adenoviruses to manipulate cell cycle regulators in vivo or in vitro. This review discusses cardiomyocyte cell cycle regulation and summarises recent data from studies manipulating the expressions and activities of cell cycle regulators in cardiomyocytes. The validity of therapeutic strategies that aim to reinstate the proliferative potential of cardiomyocytes to improve myocardial repair following injury will be discussed.
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Affiliation(s)
- Katrina A Bicknell
- School of Pharmacy, University of Reading, PO Box 226 Whiteknights, Reading Berkshire RG6 6AP, UK.
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Wu JC, Spin JM, Cao F, Lin S, Xie X, Gheysens O, Chen IY, Sheikh AY, Robbins RC, Tsalenko A, Gambhir SS, Quertermous T. Transcriptional profiling of reporter genes used for molecular imaging of embryonic stem cell transplantation. Physiol Genomics 2006; 25:29-38. [PMID: 16390873 DOI: 10.1152/physiolgenomics.00254.2005] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Stem cell therapy offers exciting promise for treatment of ischemic heart disease. Recent advances in molecular imaging techniques now allow investigators to monitor cell fate noninvasively and repetitively. Here we examine the effects of a triple-fusion reporter gene on embryonic stem (ES) cell transcriptional profiles. Murine ES cells were stably transfected with a self-inactivating lentiviral vector carrying a triple-fusion (TF) construct consisting of fluorescence, bioluminescence, and positron emission tomography (PET) reporter genes. Fluorescence-activated cell sorting (FACS) analysis allowed isolation of stably transfected populations. Microarray studies comparing gene expression in nontransduced control ES cells vs. stably transduced ES cells expressing triple fusion (ES-TF) revealed some increases in transcriptional variability. Annotation analysis showed that ES-TF cells downregulated cell cycling, cell death, and protein and nucleic acid metabolism genes while upregulating homeostatic and anti-apoptosis genes. Despite these transcriptional changes, expression of the TF reporter gene had no significant effects on ES cell viability, proliferation, and differentiation capability. Importantly, transplantation studies in murine myocardium demonstrated the feasibility of tracking ES-TF cells in living subjects using bioluminescence and PET imaging. Taken together, this is the first study to analyze in detail the effects of reporter genes on molecular imaging of ES cells.
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Affiliation(s)
- Joseph C Wu
- Division of Cardiology, Department of Medicine, Stanford University School of Medicine, Stanford, USA.
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Williams SD, Zhu H, Zhang L, Bernstein HS. Adenoviral delivery of human CDC5 promotes G2/M progression and cell division in neonatal ventricular cardiomyocytes. Gene Ther 2006; 13:837-43. [PMID: 16482203 DOI: 10.1038/sj.gt.3302737] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Heart failure results from the cumulative death of cardiomyocytes, and the inability of remaining cells to regenerate. Efforts toward transcriptional reprogramming of cardiomyocytes by overexpressing E1A or E2F1 have been limited by the inability of cardiomyocytes to enter and complete mitosis. Human CDC5 (hCDC5), a component of the pre-mRNA splicing complex, has been shown to regulate G2/M transit in asynchronously dividing cells. We now show that co-infection of recombinant adenoviruses expressing E1A/E1B and hCDC5 promotes cell cycle re-entry and G2/M progression in post-mitotic cardiomyocytes. Co-expression of E1A/E1B and hCDC5 induced nuclear localization of cyclin-dependent kinase 1 and cyclin B1, and was sufficient to promote mitotic entry as determined by an increase in mitotic index only in co-infected cells. E1A/E1B and hCDC5 promoted cell division, as evidenced by an increase in the number of cardiomyocytes following co-infection. Thus, overexpression of E1A/E1B and hCDC5 resulted in cell cycle re-entry, DNA synthesis, cell division, and an increase in cardiomyocyte number, suggesting the formation of new cardiomyocytes. These studies suggest that G1/S-phase transcriptional regulators, in combination with pre-mRNA splicing factors, such as CDC5, that regulate rate-limiting G2/M target genes may prove useful in developing therapies to stimulate myocardial regeneration.
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Affiliation(s)
- S D Williams
- Cardiovascular Research Institute, University of California, San Francisco, CA 92121, USA
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Shimada M, Namikawa-Yamada C, Nakanishi M, Murakami H. Regulation of Cdc2p and Cdc13p Is Required for Cell Cycle Arrest Induced by Defective RNA Splicing in Fission Yeast. J Biol Chem 2005; 280:32640-8. [PMID: 16049013 DOI: 10.1074/jbc.m504746200] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Screening of cdc mutants of fission yeast for those whose cell cycle arrest is independent of the DNA damage checkpoint identified the RNA splicing-deficient cdc28 mutant. A search for mutants of cdc28 cells that enter mitosis with unspliced RNA resulted in the identification of an orb5 point mutant. The orb5+ gene, which encodes a catalytic subunit of casein kinase II, was found to be required for cell cycle arrest in other mutants with defective RNA metabolism but not for operation of the DNA replication or DNA damage checkpoints. Loss of function of wee1+ or rad24+ also suppressed the arrest of several splicing mutants. Overexpression of the major B-type cyclin Cdc13p induced cdc28 cells to enter mitosis. The abundance of Cdc13p was reduced, and the phosphorylation of Cdc2p on tyrosine 15 was maintained in splicing-defective cells. These results suggest that regulation of Cdc13p and Cdc2p is required for G2 arrest in splicing mutants.
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Affiliation(s)
- Midori Shimada
- Department of Biochemistry and Cell Biology, Graduate School of Medicine, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan
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37
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Hansel DE, Dhara S, Huang RC, Ashfaq R, Deasel M, Shimada Y, Bernstein HS, Harmon J, Brock M, Forastiere A, Washington MK, Maitra A, Montgomery E. CDC2/CDK1 expression in esophageal adenocarcinoma and precursor lesions serves as a diagnostic and cancer progression marker and potential novel drug target. Am J Surg Pathol 2005; 29:390-9. [PMID: 15725809 DOI: 10.1097/00000478-200503000-00014] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Esophageal adenocarcinoma arises through well-defined precursor lesions (Barrett esophagus), although only a subset of these lesions advances to invasive adenocarcinoma. The lack of markers predicting progression in Barrett esophagus, typical presentation at advanced stage, and limitations of conventional chemotherapy result in >90% mortality for Barrett-associated adenocarcinomas. To identify potential prognostic markers and therapeutic targets, we compared gene expression profiles from Barrett-associated esophageal adenocarcinoma cell lines (BIC1, SEG1, KYAE, OE33) and normal esophageal epithelial scrapings utilizing the Affymetrix U133_A gene expression platform. We identified 560 transcripts with >3-fold up-regulation in the adenocarcinoma cell lines compared with normal epithelium. Utilizing tissue microarrays composed of normal esophageal squamous mucosa (n = 20), Barrett esophagus (n = 10), low-grade dysplasia (n = 14), high-grade dysplasia (n = 27), adenocarcinoma (n = 59), and node metastases (n = 27), we confirmed differential up-regulation of three proteins (Cdc2/Cdk1, Cdc5, and Igfbp3) in adenocarcinomas and Barrett lesions. Protein expression mirrored histologic progression; thus, 87% of low-grade dysplasias had at least focal surface Cdc2/Cdk1 and 20% had >5% surface staining; 96% of high-grade dysplasias expressed abundant surface Cdc2/Cdk1, while invasive adenocarcinoma and metastases demonstrated ubiquitous expression. Esophageal adenocarcinoma cell lines treated with the novel CDC2/CDK1 transcriptional inhibitor, tetra-O-methyl nordihydroguaiaretic acid (EM-1421, formerly named M4N) demonstrated a dose-dependent reduction in cell proliferation, paralleling down-regulation of CDC2/CDK1 transcript and protein levels. These findings suggest a role for CDC2/CDK1 in esophageal adenocarcinogenesis, both as a potential histopathologic marker of dysplasia and a putative treatment target.
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Affiliation(s)
- Donna E Hansel
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
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38
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Geigl JB, Langer S, Barwisch S, Pfleghaar K, Lederer G, Speicher MR. Analysis of gene expression patterns and chromosomal changes associated with aging. Cancer Res 2005; 64:8550-7. [PMID: 15574761 DOI: 10.1158/0008-5472.can-04-2151] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Age is the largest single risk factor for the development of cancer in mammals. Age-associated chromosomal changes, such as aneuploidy and telomere erosion, may be vitally involved in the initial steps of tumorigenesis. However, changes in gene expression specific for increased aneuploidy with age have not yet been characterized. Here, we address these questions by using a panel of fibroblast cell lines and lymphocyte cultures from young and old age groups. Oligonucleotide microarrays were used to characterize the expression of 14,500 genes. We measured telomere length and analyzed chromosome copy number changes and structural rearrangements by multicolor interphase fluorescence in situ hybridization and 7-fluorochrome multiplex fluorescence in situ hybridization, and we tried to show a relationship between gene expression patterns and chromosomal changes. These analyses revealed a number of genes involved in both the cell cycle and proliferation that are differently expressed in aged cells. More importantly, our data show an association between age-related aneuploidy and the gene expression level of genes involved in centromere and kinetochore function and in the microtubule and spindle assembly apparatus. To verify that some of these genes may also be involved in tumorigenesis, we compared the expression of these genes in chromosomally stable microsatellite instability and chromosomally unstable chromosomal instability colorectal tumor cell lines. Three genes (Notch2, H2AFY2, and CDC5L) showed similar expression differences between microsatellite instability and chromosomal instability cell lines as observed between the young and old cell cultures suggesting that they may play a role in tumorigenesis.
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Affiliation(s)
- Jochen B Geigl
- Institute of Human Genetics, Technical University, Munich, Germany
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39
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Man TK, Lu XY, Jaeweon K, Perlaky L, Harris CP, Shah S, Ladanyi M, Gorlick R, Lau CC, Rao PH. Genome-wide array comparative genomic hybridization analysis reveals distinct amplifications in osteosarcoma. BMC Cancer 2004; 4:45. [PMID: 15298715 PMCID: PMC514550 DOI: 10.1186/1471-2407-4-45] [Citation(s) in RCA: 108] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2004] [Accepted: 08/07/2004] [Indexed: 12/23/2022] Open
Abstract
Background Osteosarcoma is a highly malignant bone neoplasm of children and young adults. It is characterized by extremely complex karyotypes and high frequency of chromosomal amplifications. Currently, only the histological response (degree of necrosis) to therapy represent gold standard for predicting the outcome in a patient with non-metastatic osteosarcoma at the time of definitive surgery. Patients with lower degree of necrosis have a higher risk of relapse and poor outcome even after chemotherapy and complete resection of the primary tumor. Therefore, a better understanding of the underlying molecular genetic events leading to tumor initiation and progression could result in the identification of potential diagnostic and therapeutic targets. Methods We used a genome-wide screening method – array based comparative genomic hybridization (array-CGH) to identify DNA copy number changes in 48 patients with osteosarcoma. We applied fluorescence in situ hybridization (FISH) to validate some of amplified clones in this study. Results Clones showing gains (79%) were more frequent than losses (66%). High-level amplifications and homozygous deletions constitute 28.6% and 3.8% of tumor genome respectively. High-level amplifications were present in 238 clones, of which about 37% of them showed recurrent amplification. Most frequently amplified clones were mapped to 1p36.32 (PRDM16), 6p21.1 (CDC5L, HSPCB, NFKBIE), 8q24, 12q14.3 (IFNG), 16p13 (MGRN1), and 17p11.2 (PMP22 MYCD, SOX1,ELAC27). We validated some of the amplified clones by FISH from 6p12-p21, 8q23-q24, and 17p11.2 amplicons. Homozygous deletions were noted for 32 clones and only 7 clones showed in more than one case. These 7 clones were mapped to 1q25.1 (4 cases), 3p14.1 (4 cases), 13q12.2 (2 cases), 4p15.1 (2 cases), 6q12 (2 cases), 6q12 (2 cases) and 6q16.3 (2 cases). Conclusions This study clearly demonstrates the utility of array CGH in defining high-resolution DNA copy number changes and refining amplifications. The resolution of array CGH technology combined with human genome database suggested the possible target genes present in the gained or lost clones.
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Affiliation(s)
- Tsz-Kwong Man
- Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Xin-Yan Lu
- Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | | | - Laszlo Perlaky
- Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Charles P Harris
- Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | | | - Marc Ladanyi
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Richard Gorlick
- Department of Pediatrics, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Ching C Lau
- Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX, USA
| | - Pulivarthi H Rao
- Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX, USA
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40
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Sun X, Zhang H, Wang D, Ma D, Shen Y, Shang Y. DLP, a novel Dim1 family protein implicated in pre-mRNA splicing and cell cycle progression. J Biol Chem 2004; 279:32839-47. [PMID: 15161931 DOI: 10.1074/jbc.m402522200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In eukaryotes, primary transcripts undergo a splicing process that removes intronic sequences by a macromolecular enzyme known as the spliceosome. Both genetic and biochemical studies have revealed that essential components of the spliceosome include five small RNAs, U1, U2, U4, U5, and U6, and as many as 300 distinct proteins. Here we report the molecular cloning and functional analysis of a novel cDNA encoding for a protein of 149 amino acids. This protein has 38% amino acid sequence identity with and is evolutionally related to yeast Dim1 protein. Hence we named this protein DLP for Dim1-like protein. We showed that DLP is required for S/G(2) transition. We also demonstrated that DLP functions in cell nucleus and interacts with the U5-102-kDa protein subunit of the spliceosome, and blocking DLP protein activity led to an insufficient pre-mRNA splicing, suggesting that DLP is yet another protein component involved in pre-mRNA splicing. Collectively, our experiments indicated that DLP is implicated in not only cell cycle progression but also in a more specific molecular process such as pre-mRNA splicing.
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MESH Headings
- Alternative Splicing
- Amino Acid Sequence
- Base Sequence
- Blotting, Northern
- Blotting, Western
- Cell Cycle
- Cell Cycle Proteins/chemistry
- Cell Cycle Proteins/metabolism
- Cell Division
- Cell Line, Tumor
- Cell Nucleus/metabolism
- Cloning, Molecular
- Computational Biology
- DNA, Complementary/metabolism
- Genome
- Glutathione Transferase/metabolism
- HeLa Cells
- Humans
- Microscopy, Confocal
- Microscopy, Fluorescence
- Models, Genetic
- Molecular Sequence Data
- Nuclear Proteins
- Phylogeny
- Plasmids/metabolism
- Precipitin Tests
- Protein Binding
- RNA/metabolism
- RNA Splicing
- RNA, Messenger/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology, Amino Acid
- Spliceosomes/metabolism
- Transfection
- Two-Hybrid System Techniques
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Affiliation(s)
- Xiaojing Sun
- Department of Biochemistry and Molecular Biology, Peking University Health Science Center, 38 Xue Yuan Road, Beijing 100083, China
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41
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Vulsteke V, Beullens M, Boudrez A, Keppens S, Van Eynde A, Rider MH, Stalmans W, Bollen M. Inhibition of Spliceosome Assembly by the Cell Cycle-regulated Protein Kinase MELK and Involvement of Splicing Factor NIPP1. J Biol Chem 2004; 279:8642-7. [PMID: 14699119 DOI: 10.1074/jbc.m311466200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
NIPP1 is a ubiquitous nuclear protein that is required for spliceosome assembly. We report here that the phosphothreonine-binding Forkhead-associated domain of NIPP1 interacts with the cell cycle-regulated protein Ser/Thr kinase MELK (maternal embryonic leucine zipper kinase). The NIPP1-MELK interaction was critically dependent on the phosphorylaton of Thr-478 of MELK and was increased in lysates from mitotically arrested cells. Recombinant MELK was a potent inhibitor of an early step of spliceosome assembly in nuclear extracts. This splicing defect was also seen with a kinase-dead mutant but was absent after mutation (T478A) of the NIPP1 binding site of MELK, indicating a mediatory role for NIPP1. Our data suggest that MELK has a role in the cell cycle-regulated control of pre-mRNA splicing.
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Affiliation(s)
- Veerle Vulsteke
- Afdeling Biochemie, Faculteit Geneeskunde, Catholic University of Leuven, B-3000 Leuven, Belgium
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42
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Shimba N, Stern AS, Craik CS, Hoch JC, Dötsch V. Elimination of 13Calpha splitting in protein NMR spectra by deconvolution with maximum entropy reconstruction. J Am Chem Soc 2003; 125:2382-3. [PMID: 12603112 DOI: 10.1021/ja027973e] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Homonuclear 13C-13C couplings can significantly reduce the sensitivity and resolution of multidimensional NMR experiments. The most important of these couplings is the 13Calpha-13Cbeta coupling, and several different methods have been developed to eliminate its effect from spectra used for backbone assignment, including short or constant-time evolution periods, selectively labeled amino acids, and multiple-band decoupling sequences. In this communication we show that postacquisition deconvolution of the spectra with a maximum entropy algorithm can be superior to experimental decoupling. The method is very robust, does not introduce shifts of the resonance positions, and simplifies the measurement of the most important NMR experiments for protein backbone assignment.
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Affiliation(s)
- Nobuhisa Shimba
- Department of Pharmaceutical Chemistry, University of California-San Francisco, San Francisco, CA 94143, USA
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43
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Lau CC, Harris CP, Lu XY, Perlaky L, Gogineni S, Chintagumpala M, Hicks J, Johnson ME, Davino NA, Huvos AG, Meyers PA, Healy JH, Gorlick R, Rao PH. Frequent amplification and rearrangement of chromosomal bands 6p12-p21 and 17p11.2 in osteosarcoma. Genes Chromosomes Cancer 2003; 39:11-21. [PMID: 14603437 DOI: 10.1002/gcc.10291] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Osteosarcoma (OS) is a highly malignant bone neoplasm of children and young adults. It is characterized by chaotic karyotypes with complex marker chromosomes. We applied a combination of molecular cytogenetic techniques including comparative genomic hybridization (CGH), spectral karyotyping (SKY), and fluorescence in situ hybridization (FISH) to decipher the chromosomal complexity in a panel of 25 tumors. Combined SKY and G-banding analysis identified several novel recurrent breakpoint clusters and 9 nonrecurrent reciprocal translocations. CGH identified several recurrent chromosomal losses including 2q, 3p, 9, 10p, 12q, 13q, 14q, 15q, 16, 17p, and 18q, gains including Xp, Xq, 5q, 6p, 8q, 17p, and 20q, and high-level chromosomal amplifications at Xp11.2, 1q21-q22, 4p11, 4q12, 5p15, 6p12.1, 8q13, 8q23, 10q11, 10q22, 11q13, 11q23, 12q13-q14, 13q21-q34, 16q22, 17p11.2, 17q21-q22, 18q22, 20p11.2, and 20q12. Frequent amplification and rearrangement involving chromosomal bands at 6p12-p21 and 17p11.2 were found in 28% and 32% of cases, respectively. In an attempt to identify the genes involved in these amplicons, we used three nonoverlapping BAC clones contained within each amplicon as probes for FISH analysis, leading to a more detailed characterization and quantification of the 6p and 17p amplicons.
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Affiliation(s)
- Ching C Lau
- Department of Pediatrics, Texas Children's Cancer Center, Baylor College of Medicine, Houston, Texas 77030, USA.
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Ajuh P, Chusainow J, Ryder U, Lamond AI. A novel function for human factor C1 (HCF-1), a host protein required for herpes simplex virus infection, in pre-mRNA splicing. EMBO J 2002; 21:6590-602. [PMID: 12456665 PMCID: PMC136956 DOI: 10.1093/emboj/cdf652] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Human factor C1 (HCF-1) is needed for the expression of herpes simplex virus 1 (HSV-1) immediate-early genes in infected mammalian cells. Here, we provide evidence that HCF-1 is required for spliceosome assembly and splicing in mammalian nuclear extracts. HCF-1 interacts with complexes containing splicing snRNPs in uninfected mammalian cells and is a stable component of the spliceosome complex. We show that a missense mutation in HCF-1 in the BHK21 hamster cell line tsBN67, at the non-permissive temperature, inhibits the protein's interaction with U1 and U5 splicing snRNPs, causes inefficient spliceosome assembly and inhibits splicing. Transient expression of wild-type HCF-1 in tsBN67 cells restores splicing at the non-permissive temperature. The inhibition of splicing in tsBN67 cells correlates with the temperature-sensitive cell cycle arrest phenotype, suggesting that HCF-1-dependent splicing events may be required for cell cycle progression.
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Affiliation(s)
| | | | | | - Angus I. Lamond
- School of Life Sciences, The University of Dundee, Dow Street, Dundee DD1 5EH, UK
Corresponding author e-mail:
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Hlaing M, Shen X, Dazin P, Bernstein HS. The hypertrophic response in C2C12 myoblasts recruits the G1 cell cycle machinery. J Biol Chem 2002; 277:23794-9. [PMID: 11967266 DOI: 10.1074/jbc.m201980200] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hypertrophy occurs in postmitotic muscle as an adaptive response to various physiological and pathological stresses. Studies in vascular smooth muscle cells and primary cardiomyocytes suggest that angiotensin II-mediated hypertrophy activates signaling pathways associated with cell proliferation. Regulation of cyclin-dependent kinase (Cdk)-cyclin activities is essential to cell size control in lower eukaryotes, yet their role in the hypertrophic response in muscle is incompletely understood. We describe an in vitro model of hypertrophy in C2C12 skeletal myoblasts and demonstrate that induction of hypertrophy involves transient activation of Cdk4, subsequent phosphorylation of Rb, and release of HDAC1 from the Rb inhibitory complex. We also demonstrate that E2F-1 becomes transcriptionally active yet remains associated with Rb. We propose a model whereby partial inactivation of the Rb complex leads to derepression of a subset of E2F-1 targets necessary for cell growth without division during hypertrophy.
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Affiliation(s)
- Myint Hlaing
- Cardiovascular Research Institute, University of California, San Francisco, California 94143-0130, USA
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Engemann H, Heinzel V, Page G, Preuss U, Scheidtmann KH. DAP-like kinase interacts with the rat homolog of Schizosaccharomyces pombe CDC5 protein, a factor involved in pre-mRNA splicing and required for G2/M phase transition. Nucleic Acids Res 2002; 30:1408-17. [PMID: 11884640 PMCID: PMC101352 DOI: 10.1093/nar/30.6.1408] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
DAP-like kinase (Dlk, also termed ZIP kinase) is a leucine zipper-containing serine/threonine-specific protein kinase with as yet unknown biological function(s). Interaction partners so far identified are either transcription factors or proteins that can support or counteract apoptosis. Thus, Dlk might be involved in regulating transcription or, more generally, survival or apoptosis. Here we report on a new interaction partner, the rat homolog of Schizosaccharomyces pombe CDC5 protein, a presumptive transcription and splicing factor involved in the G(2)/M transition. In vitro, rat CDC5 forms complexes with, but is not phosphorylated by, Dlk. Rather, it was phosphorylated by an associated kinase which was identified as CK2. The interaction domain of Dlk was mapped to the leucine zipper, while that of CDC5 was mapped to the C-terminal region between residues 500 and 802. In vivo, both proteins co-localize perfectly in distinct speckle-like structures in the nucleus, some of which overlap with promyelocytic leukemia protein. Interestingly, splicing factor SC35, which also resides in speckles, was partially displaced upon overexpression of either CDC5 or Dlk, perhaps due to phosphorylation by Dlk. Together with previous data, these results suggest that Dlk might play a role in coordinating specific transcription and splicing events.
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Affiliation(s)
- Harry Engemann
- Institute of Genetics, University of Bonn, Roemerstrasse 164, D-53117 Bonn, Germany
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Burns CG, Ohi R, Mehta S, O'Toole ET, Winey M, Clark TA, Sugnet CW, Ares M, Gould KL. Removal of a single alpha-tubulin gene intron suppresses cell cycle arrest phenotypes of splicing factor mutations in Saccharomyces cerevisiae. Mol Cell Biol 2002; 22:801-15. [PMID: 11784857 PMCID: PMC133559 DOI: 10.1128/mcb.22.3.801-815.2002] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2001] [Accepted: 11/01/2001] [Indexed: 11/20/2022] Open
Abstract
Genetic and biochemical studies of Schizosaccharomyces pombe and Saccharomyces cerevisiae have identified gene products that play essential functions in both pre-mRNA splicing and cell cycle control. Among these are the conserved, Myb-related CDC5 (also known as Cef1p in S. cerevisiae) proteins. The mechanism by which loss of CDC5/Cef1p function causes both splicing and cell cycle defects has been unclear. Here we provide evidence that cell cycle arrest in a new temperature-sensitive CEF1 mutant, cef1-13, is an indirect consequence of defects in pre-mRNA splicing. Although cef1-13 cells harbor global defects in pre-mRNA splicing discovered through intron microarray analysis, inefficient splicing of the alpha-tubulin-encoding TUB1 mRNA was considered as a potential cause of the cef1-13 cell cycle arrest because cef1-13 cells arrest uniformly at G(2)/M with many hallmarks of a defective microtubule cytoskeleton. Consistent with this possibility, cef1-13 cells possess reduced levels of total TUB1 mRNA and alpha-tubulin protein. Removing the intron from TUB1 in cef1-13 cells boosts TUB1 mRNA and alpha-tubulin expression to near wild-type levels and restores microtubule stability in the cef1-13 mutant. As a result, cef1-13 tub1Deltai cells progress through mitosis and their cell cycle arrest phenotype is alleviated. Removing the TUB1 intron from two other splicing mutants that arrest at G(2)/M, prp17Delta and prp22-1 strains, permits nuclear division, but suppression of the cell cycle block is less efficient. Our data raise the possibility that although cell cycle arrest phenotypes in prp mutants can be explained by defects in pre-mRNA splicing, the transcript(s) whose inefficient splicing contributes to cell cycle arrest is likely to be prp mutant dependent.
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Affiliation(s)
- C Geoffrey Burns
- Howard Hughes Medical Institute, Department of Cell Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
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Johnson LM, Too CK. Prolactin, interleukin-2 and FGF-2 stimulate expression, nuclear distribution and DNA-binding of rat homolog of pombe Cdc5 in Nb2 T lymphoma cells. Mol Cell Endocrinol 2001; 184:151-61. [PMID: 11694351 DOI: 10.1016/s0303-7207(01)00585-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Pombe and human Cdc5 have been implicated in G2/M progression, but recently Cdc5 was identified as a component of a multiprotein complex essential for pre-mRNA splicing. We have previously isolated a prolactin (PRL)-inducible partial cDNA (1907 bp) encoding rat Cdc5. In the present study, the full length rCdc5 sequence (2847 bp) was obtained by 5'-RACE and cytokine regulation of Cdc5 expression was examined. PRL and interleukin-2 (IL2) act as mitogens in Nb2 T-lymphoma cells. Fibroblast growth factor (FGF-2) is not mitogenic in Nb2 cells but inhibits apoptosis of PRL-deprived cells. This study showed that PRL, IL-2 and FGF-2 rapidly increased Nb2 Cdc5 expression (3.4 kb mRNA) to reach 2-3-fold above controls at 4 h, and Cdc5 mRNA levels remained elevated at 24 h. There was a corresponding 2-3-fold increase in Cdc5 protein (105 kDa) levels at 24 h. Immunoblotting and fluorescent confocal microscopy showed predominant nuclear/perinuclear Cdc5 in quiescent Nb2 cells. PRL or FGF-2 treatment transiently increased nuclear Cdc5-specific immunofluorescence at 4 h but IL-2 gave maximal nuclear accumulation of Cdc5 at 24 h. The deduced rCdc5 protein has approximately 98% amino acid identity with human Cdc5. Like other Cdc5 family members, the N-terminus of rCdc5 contains two repeats of a DNA-binding domain found in a-, b- and c-Myb. Gel shift assays using (32)P-labeled Myb consensus oligonucleotides revealed two Myb-specific DNA-protein complexes in Nb2 nuclear extracts. Formation of both complexes was increased by PRL or FGF-2 at 1-5 and at 20 h and was partially inhibited by anti-Myb or anti-Cdc5 antibodies. In summary, rapid activation of Cdc5 in response to mitogenic and non-mitogenic stimuli suggests a complex role for Cdc5 in cellular regulation and this may not be restricted to mitotic entry or G2/M progression as previously supposed.
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Affiliation(s)
- L M Johnson
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Sir Charles Tupper Medical Building, Dalhousie University, Halifax, NS B3H 4H7, Canada
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Ajuh P, Sleeman J, Chusainow J, Lamond AI. A direct interaction between the carboxyl-terminal region of CDC5L and the WD40 domain of PLRG1 is essential for pre-mRNA splicing. J Biol Chem 2001; 276:42370-81. [PMID: 11544257 DOI: 10.1074/jbc.m105453200] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human proteins CDC5L (hCDC5) and PLRG1 are both highly conserved components of a multiprotein complex that is a subunit of the spliceosome. The respective homologues in yeast of both proteins are also associated with a sub-spliceosomal multiprotein complex that has been shown to be important for pre-mRNA splicing. We show that these two human proteins are associated in vivo and will interact directly in vitro. The regions containing the interacting domains in both proteins have been identified. Our results indicate that the carboxyl-terminal region of CDC5L and the WD40 domain of PLRG1 are essential for direct interaction between both proteins. By using a bacterially expressed mutant protein, containing the PLRG1 interacting domain in CDC5L, we show that the CDC5L-PLRG1 interaction in HeLa nuclear extract can be disrupted causing pre-mRNA splicing to be inhibited. Thus, a direct interaction between the CDC5L protein and PLRG1 in the CDC5L complex is essential for pre-mRNA splicing progression.
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Affiliation(s)
- P Ajuh
- School of Life Sciences, the University of Dundee, Dow Street, Dundee DD1 5EH, Scotland, United Kingdom
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Abstract
We have started to develop new NMR pulse sequences that detect carbon magnetization during the acquisition period. These experiments have become possible with the recent introduction of cryogenic probe heads. We show that a careful design of these carbon-detected experiments can at least partially compensate for the inherent lower sensitivity of carbon detection compared to proton detection. We discuss potential applications of carbon detection and demonstrate a deconvolution technique that removes the effects of carbon-carbon couplings from the spectra.
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Affiliation(s)
- Z Serber
- Graduate Group in Biophysics, University of California San Francisco, San Francisco, CA 94143 USA
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