1
|
Kataria A, Tyagi S. Domain architecture and protein-protein interactions regulate KDM5A recruitment to the chromatin. Epigenetics 2023; 18:2268813. [PMID: 37838974 PMCID: PMC10578193 DOI: 10.1080/15592294.2023.2268813] [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: 05/18/2023] [Accepted: 10/01/2023] [Indexed: 10/17/2023] Open
Abstract
Tri-methylation of Histone 3 lysine 4 (H3K4) is an important epigenetic modification whose deposition and removal can affect the chromatin at structural and functional levels. KDM5A is one of the four known H3K4-specific demethylases. It is a part of the KDM5 family, which is characterized by a catalytic Jumonji domain capable of removing H3K4 di- and tri-methylation marks. KDM5A has been found to be involved in multiple cellular processes such as differentiation, metabolism, cell cycle, and transcription. Its link to various diseases, including cancer, makes KDM5A an important target for drug development. However, despite several studies outlining its significance in various pathways, our lack of understanding of its recruitment and function at the target sites on the chromatin presents a challenge in creating effective and targeted treatments. Therefore, it is essential to understand the recruitment mechanism of KDM5A to chromatin, and its activity therein, to comprehend how various roles of KDM5A are regulated. In this review, we discuss how KDM5A functions in a context-dependent manner on the chromatin, either directly through its structural domain, or through various interacting partners, to bring about a diverse range of functions.
Collapse
Affiliation(s)
- Avishek Kataria
- Laboratory of Cell Cycle Regulation, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
- Graduate Studies, Manipal Academy of Higher Education, Manipal, India
| | - Shweta Tyagi
- Laboratory of Cell Cycle Regulation, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
| |
Collapse
|
2
|
Pavlenko E, Ruengeler T, Engel P, Poepsel S. Functions and Interactions of Mammalian KDM5 Demethylases. Front Genet 2022; 13:906662. [PMID: 35899196 PMCID: PMC9309374 DOI: 10.3389/fgene.2022.906662] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 06/06/2022] [Indexed: 12/26/2022] Open
Abstract
Mammalian histone demethylases of the KDM5 family are mediators of gene expression dynamics during developmental, cellular differentiation, and other nuclear processes. They belong to the large group of JmjC domain containing, 2-oxoglutarate (2-OG) dependent oxygenases and target methylated lysine 4 of histone H3 (H3K4me1/2/3), an epigenetic mark associated with active transcription. In recent years, KDM5 demethylases have gained increasing attention due to their misregulation in many cancer entities and are intensively explored as therapeutic targets. Despite these implications, the molecular basis of KDM5 function has so far remained only poorly understood. Little is known about mechanisms of nucleosome recognition, the recruitment to genomic targets, as well as the local regulation of demethylase activity. Experimental evidence suggests close physical and functional interactions with epigenetic regulators such as histone deacetylase (HDAC) containing complexes, as well as the retinoblastoma protein (RB). To understand the regulation of KDM5 proteins in the context of chromatin, these interactions have to be taken into account. Here, we review the current state of knowledge on KDM5 function, with a particular emphasis on molecular interactions and their potential implications. We will discuss and outline open questions that need to be addressed to better understand histone demethylation and potential demethylation-independent functions of KDM5s. Addressing these questions will increase our understanding of histone demethylation and allow us to develop strategies to target individual KDM5 enzymes in specific biological and disease contexts.
Collapse
Affiliation(s)
- Egor Pavlenko
- University of Cologne, Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and University Hospital, Cologne, Germany
| | - Till Ruengeler
- University of Cologne, Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and University Hospital, Cologne, Germany
| | - Paulina Engel
- University of Cologne, Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and University Hospital, Cologne, Germany
| | - Simon Poepsel
- University of Cologne, Center for Molecular Medicine Cologne (CMMC), Faculty of Medicine and University Hospital, Cologne, Germany
- Cologne Excellence Cluster for Cellular Stress Responses in Ageing-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
- *Correspondence: Simon Poepsel,
| |
Collapse
|
3
|
Zargar ZU, Kimidi MR, Tyagi S. Dynamic site-specific recruitment of RBP2 by pocket protein p130 modulates H3K4 methylation on E2F-responsive promoters. Nucleic Acids Res 2019; 46:174-188. [PMID: 29059406 PMCID: PMC5758877 DOI: 10.1093/nar/gkx961] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 10/07/2017] [Indexed: 02/01/2023] Open
Abstract
The Histone 3 lysine 4 methylation (H3K4me3) mark closely correlates with active transcription. E2F-responsive promoters display dynamic changes in H3K4 methylation during the course of cell cycle progression. However, how and when these marks are reset, is not known. Here we show that the retinoblastoma binding protein RBP2/KDM5A, capable of removing tri-methylation marks on H3K4, associates with the E2F4 transcription factor via the pocket protein-p130-in a cell-cycle-stage specific manner. The association of RBP2 with p130 is LxCxE motif dependent. RNAi experiments reveal that p130 recruits RBP2 to E2F-responsive promoters in early G1 phase to bring about H3K4 demethylation and gene repression. A point mutation in LxCxE motif of RBP2 renders it incapable of p130-interaction and hence, repression of E2F-regulated gene promoters. We also examine how RBP2 may be recruited to non-E2F responsive promoters. Our studies provide insight into how the chromatin landscape needs to be adjusted rapidly and periodically during cell-cycle progression, concomitantly with temporal transcription, to bring about expression/repression of specific gene sets.
Collapse
Affiliation(s)
- Zaffer Ullah Zargar
- Laboratory of Cell Cycle Regulation, Centre for DNA Fingerprinting and Diagnostics (CDFD), Nampally, Hyderabad 500001, India.,Graduate Studies, Manipal University, Manipal, India
| | - Mallikharjuna Rao Kimidi
- Laboratory of Cell Cycle Regulation, Centre for DNA Fingerprinting and Diagnostics (CDFD), Nampally, Hyderabad 500001, India
| | - Shweta Tyagi
- Laboratory of Cell Cycle Regulation, Centre for DNA Fingerprinting and Diagnostics (CDFD), Nampally, Hyderabad 500001, India
| |
Collapse
|
4
|
Kong SY, Kim W, Lee HR, Kim HJ. The histone demethylase KDM5A is required for the repression of astrocytogenesis and regulated by the translational machinery in neural progenitor cells. FASEB J 2018; 32:1108-1119. [PMID: 29212818 PMCID: PMC6266631 DOI: 10.1096/fj.201700780r] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 11/27/2017] [Indexed: 01/20/2023]
Abstract
Histone demethylases are known to play important roles in the determination of the fate of stem cells and in cancer progression. In this study, we show that the lysine 4 of histone H3 (H3K4), lysine-specific demethylase 5A (KDM5A) is essential for the repression of astrocyte differentiation in neural progenitor cells (NPCs), and its expression is regulated by translational machinery. Knockdown of KDM5A in NPCs increased astrocytogenesis, and conversely, KDM5A overexpression reduced the transcriptional activity of the Gfap promoter. Induction of astrocytogenesis by ciliary neurotrophic factor (CNTF) or small interfering RNA-induced knockdown of KDM5A decreased KDM5A recruitment to the Gfap promoter and increased H3K4 methylation. The transcript level of Kdm5a was high, whereas KDM5A protein level was low in CNTF induced astrocytes. During astroglial differentiation, translational activity indicated by the phosphorylation of eukaryotic translation initiation factor (eIF)4E was decreased. Treatment of NPCs with the cercosporamide, a MAPK-interacting kinases inhibitor, reduced eIF4E phosphorylation and KDM5A protein expression, increased GFAP levels, and enhanced astrocytogenesis. These data suggest that KDM5A is a key regulator that maintains NPCs in an undifferentiated state by repressing astrocytogenesis and that its expression is translationally controlled during astrocyte differentiation. Thus, KDM5A is a promising target for the modulation of NPC fate.-Kong, S.-Y., Kim, W., Lee, H.-R., Kim, H.-J. The histone demethylase KDM5A is required for the repression of astrocytogenesis and regulated by the translational machinery in neural progenitor cells.
Collapse
Affiliation(s)
- Sun-Young Kong
- Laboratory of Molecular and Stem Cell Pharmacology, College of Pharmacy,
Chung-Ang University, Seoul, South Korea
| | - Woosuk Kim
- Laboratory of Molecular and Stem Cell Pharmacology, College of Pharmacy,
Chung-Ang University, Seoul, South Korea
| | - Ha-Rim Lee
- Laboratory of Molecular and Stem Cell Pharmacology, College of Pharmacy,
Chung-Ang University, Seoul, South Korea
| | - Hyun-Jung Kim
- Laboratory of Molecular and Stem Cell Pharmacology, College of Pharmacy,
Chung-Ang University, Seoul, South Korea
| |
Collapse
|
5
|
APC/C and retinoblastoma interaction: cross-talk of retinoblastoma protein with the ubiquitin proteasome pathway. Biosci Rep 2016; 36:BSR20160152. [PMID: 27402801 PMCID: PMC5025812 DOI: 10.1042/bsr20160152] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 07/08/2016] [Indexed: 12/15/2022] Open
Abstract
The ubiquitin (Ub) ligase anaphase promoting complex/cyclosome (APC/C) and the tumour suppressor retinoblastoma protein (pRB) play key roles in cell cycle regulation. APC/C is a critical regulator of mitosis and G1-phase of the cell cycle whereas pRB keeps a check on proliferation by inhibiting transition to the S-phase. APC/C and pRB interact with each other via the co-activator of APC/C, FZR1, providing an alternative pathway of regulation of G1 to S transition by pRB using a post-translational mechanism. Both pRB and FZR1 have complex roles and are implicated not only in regulation of cell proliferation but also in differentiation, quiescence, apoptosis, maintenance of chromosomal integrity and metabolism. Both are also targeted by transforming viruses. We discuss recent advances in our understanding of the involvement of APC/C and pRB in cell cycle based decisions and how these insights will be useful for development of anti-cancer and anti-viral drugs.
Collapse
|
6
|
Abstract
Human retinoblastoma gene RB1 is the first tumor suppressor gene (TSG) isolated by positional cloning in 1986. RB is extensively studied for its ability to regulate cell cycle by binding to E2F1 and inhibiting the transcriptional activity of the latter. In human embryonic stem cells (ESCs), only a minute trace of RB is found in complex with E2F1. Increased activity of RB triggers differentiation, cell cycle arrest, and cell death. On the other hand, inactivation of the entire RB family (RB1, RBL1, and RBL2) in human ESC induces G2/M arrest and cell death. These observations indicate that both loss and overactivity of RB could be lethal for the stemness of cells. A question arises why inactive RB is required for the survival and stemness of cells? To shed some light on this question, we analyzed the RB-binding proteins. In this review we have focused on 27 RB-binding partners that may have potential roles in different aspects of stem cell biology.
Collapse
Affiliation(s)
- M Mushtaq
- Karolinska Institutet, Stockholm, Sweden
| | | | - E V Kashuba
- Karolinska Institutet, Stockholm, Sweden; R.E. Kavetsky Institute of Experimental Pathology, Oncology and Radiobiology, NASU, Kyiv, Ukraine.
| |
Collapse
|
7
|
Zhou D, Kannappan V, Chen X, Li J, Leng X, Zhang J, Xuan S. RBP2 induces stem-like cancer cells by promoting EMT and is a prognostic marker for renal cell carcinoma. Exp Mol Med 2016; 48:e238. [PMID: 27282106 PMCID: PMC4929691 DOI: 10.1038/emm.2016.37] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 12/30/2015] [Accepted: 01/06/2016] [Indexed: 12/13/2022] Open
Abstract
Renal cell carcinoma (RCC), one of the most common kidney cancers, has a poor prognosis. Epithelial to mesenchymal transition (EMT) is a hallmark of carcinoma invasion and metastasis. Several studies have examined the molecular regulation of EMT, but the relationship between histone demethylases and EMT is little understood. In this study, we investigated the role of retinoblastoma-binding protein-2 (RBP2), a histone demethylase that is highly expressed in RCC and is positively correlated with poor RCC prognosis in the regulation of EMT. We found that ectopic overexpression of RBP2 can induce cancer stem cell-like (CSC) phenotypes through EMT in RCC cells by converting them to a more mesenchymal phenotype. This results in increased resistance to apoptosis, which leads to enhanced tumor growth in xenograft models. Together, our data show that RBP2 is an epigenetic regulator that has an important role in the initiation of CSC phenotypes through EMT, leading to tumor progression. RBP2 is also a novel biomolecule for RCC diagnosis, and prognosis and may be a therapeutic target.
Collapse
MESH Headings
- Animals
- Biomarkers, Tumor/analysis
- Biomarkers, Tumor/metabolism
- Carcinogenesis/metabolism
- Carcinogenesis/pathology
- Carcinoma, Renal Cell/diagnosis
- Carcinoma, Renal Cell/metabolism
- Carcinoma, Renal Cell/pathology
- Cell Line, Tumor
- Epithelial-Mesenchymal Transition
- Follow-Up Studies
- Humans
- Kidney/metabolism
- Kidney/pathology
- Kidney Neoplasms/diagnosis
- Kidney Neoplasms/metabolism
- Kidney Neoplasms/pathology
- Mice, Inbred BALB C
- Mice, Nude
- Neoplastic Stem Cells/metabolism
- Neoplastic Stem Cells/pathology
- Prognosis
- Retinol-Binding Proteins, Cellular/analysis
- Retinol-Binding Proteins, Cellular/metabolism
Collapse
Affiliation(s)
- Dahai Zhou
- College of Medicine and Pharmacy, Ocean University of China, Qingdao, China
- Department of Urology, 401 Hospital of PLA, Qingdao, China
| | - Vinodh Kannappan
- Research Institute in Healthcare Science, Faculty of Science & Engineering, University of Wolverhampton, Wolverhampton, UK
| | | | - Jingqin Li
- Department of Urology, 401 Hospital of PLA, Qingdao, China
| | - Xuefeng Leng
- Department of Urology, 401 Hospital of PLA, Qingdao, China
| | - Jinping Zhang
- Department of Urology, 401 Hospital of PLA, Qingdao, China
| | - Shiying Xuan
- College of Medicine and Pharmacy, Ocean University of China, Qingdao, China
- Qingdao Municipal Hospital, Qingdao, China
| |
Collapse
|
8
|
Flowers S, Patel PJ, Gleicher S, Amer K, Himelman E, Goel S, Moran E. p107-Dependent recruitment of SWI/SNF to the alkaline phosphatase promoter during osteoblast differentiation. Bone 2014; 69:47-54. [PMID: 25182511 PMCID: PMC5222550 DOI: 10.1016/j.bone.2014.08.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 08/11/2014] [Accepted: 08/16/2014] [Indexed: 12/28/2022]
Abstract
The retinoblastoma protein family is intimately involved in the regulation of tissue specific gene expression during mesenchymal stem cell differentiation. The role of the following proteins, pRB, p107 and p130, is particularly significant in differentiation to the osteoblast lineage, as human germ-line mutations of RB1 greatly increase susceptibility to osteosarcoma. During differentiation, pRB directly targets certain osteogenic genes for activation, including the alkaline phosphatase-encoding gene Alpl. Chromatin immunoprecipitation (ChIP) assays indicate that Alpl is targeted by p107 in differentiating osteoblasts selectively during activation with the same dynamics as pRB, which suggests that p107 helps promote Alpl activation. Mouse models indicate overlapping roles for pRB and p107 in bone and cartilage formation, but very little is known about direct tissue-specific gene targets of p107, or the consequences of targeting by p107. Here, the roles of p107 and pRB were compared using shRNA-mediated knockdown genetics in an osteoblast progenitor model, MC3T3-E1 cells. The results show that p107 has a distinct role along with pRB in induction of Alpl. Deficiency of p107 does not impede recruitment of transcription factors recognized as pRB co-activation partners at the promoter; however, p107 is required for the efficient recruitment of an activating SWI/SNF chromatin-remodeling complex, an essential event in Alpl induction.
Collapse
Affiliation(s)
- Stephen Flowers
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Parth J Patel
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Stephanie Gleicher
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Kamal Amer
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Eric Himelman
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Shruti Goel
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA
| | - Elizabeth Moran
- Department of Orthopaedics, New Jersey Medical School, Rutgers, the State University of New Jersey, Newark, NJ 07103, USA.
| |
Collapse
|
9
|
Cao J, Liu Z, Cheung WKC, Zhao M, Chen SY, Chan SW, Booth CJ, Nguyen DX, Yan Q. Histone demethylase RBP2 is critical for breast cancer progression and metastasis. Cell Rep 2014; 6:868-77. [PMID: 24582965 DOI: 10.1016/j.celrep.2014.02.004] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Revised: 12/31/2013] [Accepted: 02/03/2014] [Indexed: 12/20/2022] Open
Abstract
Metastasis is a major clinical challenge for cancer treatment. Emerging evidence suggests that aberrant epigenetic modifications contribute significantly to tumor formation and progression. However, the drivers and roles of such epigenetic changes in tumor metastasis are still poorly understood. Using bioinformatic analysis of human breast cancer gene-expression data sets, we identified histone demethylase RBP2 as a putative mediator of metastatic progression. By using both human breast cancer cells and genetically engineered mice, we demonstrated that RBP2 is critical for breast cancer metastasis to the lung in multiple in vivo models. Mechanistically, RBP2 promotes metastasis as a pleiotropic positive regulator of many metastasis genes, including TNC. In addition, RBP2 loss suppresses tumor formation in MMTV-neu transgenic mice. These results suggest that therapeutic targeting of RBP2 is a potential strategy for inhibition of tumor progression and metastasis.
Collapse
Affiliation(s)
- Jian Cao
- Department of Pathology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Zongzhi Liu
- Department of Pathology, Yale School of Medicine, New Haven, CT 06520, USA
| | - William K C Cheung
- Department of Pathology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Minghui Zhao
- Department of Pathology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Sophia Y Chen
- Department of Pathology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Siew Wee Chan
- Cancer and Developmental Cell Biology Division, Institute of Molecular and Cell Biology, 61 Biopolis Drive, Singapore 138673, Singapore
| | - Carmen J Booth
- Section of Comparative Medicine, Yale School of Medicine, New Haven, CT 06520, USA
| | - Don X Nguyen
- Department of Pathology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Qin Yan
- Department of Pathology, Yale School of Medicine, New Haven, CT 06520, USA.
| |
Collapse
|
10
|
Chai SY, Smith R, Fitter JT, Mitchell C, Pan X, Ilicic M, Maiti K, Zakar T, Madsen G. Increased progesterone receptor A expression in labouring human myometrium is associated with decreased promoter occupancy by the histone demethylase JARID1A. Mol Hum Reprod 2014; 20:442-53. [PMID: 24442343 DOI: 10.1093/molehr/gau005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Progesterone regulates female reproductive function predominantly through two nuclear progesterone receptors (PRs), PR-A and PR-B. During human parturition myometrial PR expression is altered to favour PR-A, which activates pro-labour genes. We have previously identified histone H3 lysine 4 trimethylation (H3K4me3) as an activator of myometrial PR-A expression at labour. To further elucidate the mechanisms regulating PR isoform expression in the human uterus at labour, we have (i) determined the methylation profile of the cytosine-guanine dinucleotides (CpG) island in the promoter region of the PR gene and (ii) identified the histone-modifying enzymes that target the H3K4me3 mark at the PR promoters in term and preterm human myometrial tissues obtained before and after labour onset. Bisulphite sequencing showed that despite overall low levels of PR CpG island methylation, there was a significant decrease in methylated CpGs with labour in both preterm (P < 0.05) and term (P < 0.01) groups downstream of the PR-B transcription start site. This methylation change was not associated with altered PR-B expression, but may contribute to the increase in PR-A expression with labour. Chromatin immunoprecipitation revealed that the histone methyltransferase, SET and MYND domain-containing protein 3 (SMYD3), bound to the PR gene at significantly higher levels at the PR-A promoter compared with the PR-B promoter (P < 0.010), with no labour-associated changes observed. The H3K4 demethylase, Jumonji AT-rich interactive domain 1A (JARID1A), also bound to the PR-A, but not to the PR-B promoter prior to term labour, and decreased significantly at the onset of labour (P = 0.014), providing a mechanism for the previously reported increase in H3K4me3 level and PR-A expression with labour. Our studies suggest that epigenetic changes mediated by JARID1A, SMYD3 and DNA methylation may be responsible, at least in part, for the functional progesterone withdrawal that precipitates human labour.
Collapse
Affiliation(s)
- S Y Chai
- Mothers and Babies Research Centre, Hunter Medical Research Institute, University of Newcastle, Newcastle, Australia
| | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Abstract
Similar to genetic alterations, epigenetic aberrations contribute significantly to tumor initiation and progression. In many cases, these changes are caused by activation or inactivation of the regulators that maintain epigenetic states. Here we review our current knowledge on the KDM5/JARID1 family of histone demethylases. This family of enzymes contains a JmjC domain and is capable of removing tri- and di- methyl marks from lysine 4 on histone H3. Among these proteins, RBP2 mediates drug resistance while JARID1B is required for melanoma maintenance. Preclinical studies suggest inhibition of these enzymes can suppress tumorigenesis and provide strong rationale for development of their inhibitors for use in cancer therapy.
Collapse
|
12
|
Yaseen A, Li Y. Dinosolve: a protein disulfide bonding prediction server using context-based features to enhance prediction accuracy. BMC Bioinformatics 2013; 14 Suppl 13:S9. [PMID: 24267383 PMCID: PMC3849605 DOI: 10.1186/1471-2105-14-s13-s9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Background Disulfide bonds play an important role in protein folding and structure stability. Accurately predicting disulfide bonds from protein sequences is important for modeling the structural and functional characteristics of many proteins. Methods In this work, we introduce an approach of enhancing disulfide bonding prediction accuracy by taking advantage of context-based features. We firstly derive the first-order and second-order mean-force potentials according to the amino acid environment around the cysteine residues from large number of cysteine samples. The mean-force potentials are integrated as context-based scores to estimate the favorability of a cysteine residue in disulfide bonding state as well as a cysteine pair in disulfide bond connectivity. These context-based scores are then incorporated as features together with other sequence and evolutionary information to train neural networks for disulfide bonding state prediction and connectivity prediction. Results The 10-fold cross validated accuracy is 90.8% at residue-level and 85.6% at protein-level in classifying an individual cysteine residue as bonded or free, which is around 2% accuracy improvement. The average accuracy for disulfide bonding connectivity prediction is also improved, which yields overall sensitivity of 73.42% and specificity of 91.61%. Conclusions Our computational results have shown that the context-based scores are effective features to enhance the prediction accuracies of both disulfide bonding state prediction and connectivity prediction. Our disulfide prediction algorithm is implemented on a web server named "Dinosolve" available at: http://hpcr.cs.odu.edu/dinosolve.
Collapse
|
13
|
Lee WY, Lee PPF, Yan YK, Lau M. Cytotoxic copper(ii) salicylaldehyde semicarbazone complexes: Mode of action and proteomic analysis. Metallomics 2010; 2:694-705. [DOI: 10.1039/c0mt00016g] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
|
14
|
Inaba H, Kuboniwa M, Bainbridge B, Yilmaz O, Katz J, Shiverick KT, Amano A, Lamont RJ. Porphyromonas gingivalis invades human trophoblasts and inhibits proliferation by inducing G1 arrest and apoptosis. Cell Microbiol 2009; 11:1517-32. [PMID: 19523155 DOI: 10.1111/j.1462-5822.2009.01344.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Porphyromonas gingivalis is an oral pathogen that is also associated with serious systemic conditions such as preterm delivery. Here we investigated the interaction between P. gingivalis and a cell line of extravillous trophoblasts (HTR-8) derived from the human placenta. P. gingivalis internalized within HTR-8 cells and inhibited proliferation through induction of arrest in the G1 phase of the cell cycle. G1 arrest was associated with decreased expression of cyclin D and of CDKs 2, 4 and 6. In addition, levels of CDK inhibitors p15, p16, p18 and p21 were increased following P. gingivalis infection. The amount of Rb was diminished by P. gingivalis, and transient overexpression of Rb, with concomitant upregulation of phospho-Rb, relieved P. gingivalis-induced G1 arrest. HTR-8 cells halted in the G1 phase became apoptotic, and apoptosis was accompanied by an increase in the ratio of Bax/Bcl-2 and increased activity of caspases 3, 7 and 9. HTR-8 cells infected with P. gingivalis also exhibited a sustained activation of ERK1/2, and knock-down of ERK1/2 activity with siRNA abrogated both G1 arrest and apoptosis. Thus, P. gingivalis can invade placental trophoblasts and induce G1 arrest and apoptosis through pathways involving ERK1/2 and its downstream effectors, properties that provide a mechanistic basis for pathogenicity in complications of pregnancy.
Collapse
Affiliation(s)
- Hiroaki Inaba
- Department of Oral Biology, College of Dentistry and Emerging Pathogens Institute, University of Florida, Gainesville, 32610, USA
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Hayakawa T, Ohtani Y, Hayakawa N, Shinmyozu K, Saito M, Ishikawa F, Nakayama JI. RBP2 is an MRG15 complex component and down-regulates intragenic histone H3 lysine 4 methylation. Genes Cells 2007; 12:811-26. [PMID: 17573780 DOI: 10.1111/j.1365-2443.2007.01089.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
MRG15 is a conserved chromodomain protein that associates with histone deacetylases (HDACs) and Tip60-containing histone acetyltransferase (HAT) complexes. Here we further characterize MRG15-containing complexes and show a functional link between MRG15 and histone H3K4 demethylase activity in mammalian cells. MRG15 was predominantly localized to discrete nuclear subdomains enriched for Ser(2)-phosphorylated RNA polymerase II, suggesting it is involved specifically with active transcription. Protein analysis of the MRG15-containing complexes led to the identification of RBP2, a JmjC domain-containing protein. Remarkably, over-expression of RBP2 greatly reduced the H3K4 methylation in culture human cells in vivo, and recombinant RBP2 efficiently removed H3K4 methylation of histone tails in vitro. Knockdown of RBP2 resulted in increased H3K4 methylation levels within transcribed regions of active genes. Our findings demonstrate that RBP2 associated with MRG15 complex to maintain reduced H3K4 methylation at transcribed regions, which may ensure the transcriptional elongation state.
Collapse
Affiliation(s)
- Tomohiro Hayakawa
- Laboratory for Chromatin Dynamics, Center for Developmental Biology, RIKEN, Kobe, Hyogo 650-0047, Japan
| | | | | | | | | | | | | |
Collapse
|
16
|
Klose RJ, Yan Q, Tothova Z, Yamane K, Erdjument-Bromage H, Tempst P, Gilliland DG, Zhang Y, Kaelin WG. The Retinoblastoma Binding Protein RBP2 Is an H3K4 Demethylase. Cell 2007; 128:889-900. [PMID: 17320163 DOI: 10.1016/j.cell.2007.02.013] [Citation(s) in RCA: 331] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Revised: 12/22/2006] [Accepted: 02/08/2007] [Indexed: 12/13/2022]
Abstract
Changes in histone methylation status regulate chromatin structure and DNA-dependent processes such as transcription. Recent studies indicate that, analogous to other histone modifications, histone methylation is reversible. Retinoblastoma binding protein 2 (RBP2), a nuclear protein implicated in the regulation of transcription and differentiation by the retinoblastoma tumor suppressor protein, contains a JmjC domain recently defined as a histone demethylase signature motif. Here we report that RBP2 is a demethylase that specifically catalyzes demethylation on H3K4, whose methylation is normally associated with transcriptionally active genes. RBP2-/- mouse cells displayed enhanced transcription of certain cytokine genes, which, in the case of SDF1, was associated with increased H3K4 trimethylation. Furthermore, RBP2 specifically demethylated H3K4 in biochemical and cell-based assays. These studies provide mechanistic insights into transcriptional regulation by RBP2 and provide the first example of a mammalian enzyme capable of erasing trimethylated H3K4.
Collapse
Affiliation(s)
- Robert J Klose
- Howard Hughes Medical Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Chinnadurai G. CtIP, a candidate tumor susceptibility gene is a team player with luminaries. Biochim Biophys Acta Rev Cancer 2005; 1765:67-73. [PMID: 16249056 DOI: 10.1016/j.bbcan.2005.09.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Revised: 09/19/2005] [Accepted: 09/20/2005] [Indexed: 10/25/2022]
Abstract
CtIP is a nuclear protein conserved among vertebrates that was discovered as a cofactor of the transcriptional corepressor CtBP. CtIP also interacts with the tumor suppressors such as BRCA1 and the pRb family members through binding sites that are frequently mutated in human cancers. CtIP is a target for BRCA1-dependent phosphorylation by the ATM kinase induced by DNA double strand breakage. CtIP plays a role in DNA-damage-induced cell cycle checkpoint control at the G2/M transition. Homozygous inactivation of the Ctip gene causes very early embryonic lethality during mouse development. The Ctip(-/-) embryo cells are arrested in G1 and do not enter S phase. Depletion of Ctip in established mouse embryo fibroblasts arrests cells in G1 and results in an accumulation of hypophosphorylated Rb and the Cdk inhibitor p21, suggesting that CtIP is also a critical regulator of G1/S transition of the cell cycle. The Ctip gene contains a mononucleotide (A9) repeat and one of the alleles is mutated at a high frequency in colon cancers with microsatellite instability. The Ctip(+/-) mice develop multiple types of tumors suggesting that haploid insufficiency of Ctip leads to tumorigenesis. Among the various tumor types observed in Ctip(+/-) heterozygous mice, large lymphomas are prevalent. Recent studies raise the possibility that Ctip may itself be a tumor susceptibility gene and suggest that it might be important for the activities of tumor suppressors BRCA1, pRb family proteins and Ikaros family members.
Collapse
Affiliation(s)
- G Chinnadurai
- Institute for Molecular Virology, Saint Louis University School of Medicine, 3681 Park Avenue, St. Louis, Missouri 63110, USA.
| |
Collapse
|
18
|
Roesch A, Becker B, Meyer S, Wild P, Hafner C, Landthaler M, Vogt T. Retinoblastoma-binding protein 2-homolog 1: a retinoblastoma-binding protein downregulated in malignant melanomas. Mod Pathol 2005; 18:1249-57. [PMID: 15803180 DOI: 10.1038/modpathol.3800413] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In malignant melanomas, the loss of cell cycle control is thought to be due to a lack of retinoblastoma protein (pRb)-activity. Members of the previously described family of retinoblastoma-binding proteins (RBPs) are supposed to act as pRb-modulating factors. Based on RNA-fingerprinting of normal human melanocytes, we previously described a new family member with high sequence homology to the retinoblastoma-binding protein-2 (RBP-2), termed RBP2-Homolog 1 (RBP2-H1). Based on its UVB responsiveness, it was hypothesized that this gene may also play a role in melanocytic tumors. In the present study, we can confirm by real-time RT-PCR (six common melanocytic nevi, five advanced nodular melanomas and seven melanoma metastases) and immunohistochemistry (tissue microarrays: 52 melanocytic nevi, 60 melanomas, 60 metastases; and conventional sections: five common nevi, four advanced nodular melanomas, five melanoma metastases) that RBP2-H1 expression is progressively downregulated in advanced and metastatic melanomas in vivo with a certain intratumoral heterogeneity. Whereas benign melanocytic nevi are RBP2-H1 positive in about 70% of the cases, a lack of RBP2-H1 expression was found in 90% of the primary malignant melanomas and 70% of the melanoma metastases, respectively. Interestingly, a similar deficiency can be found in glioblastomas, but not epithelial cancers. In accordance to the in vivo data, established melanoma cell lines exhibit low but heterogeneous levels of RBP2-H1 expression. By co-immunoprecipitation, we provide the first evidence that a subfraction of total RBP2-H1 can bind to pRb, which makes this protein a true pRb-interacting factor. We conclude that loss of RBP2-H1 is a common finding in the progression of malignant melanomas. Since a direct interaction of RBP2-H1 and pRb seems possible, the loss of RBP2-H1 may possibly contribute to uncontrolled growth in malignant melanomas.
Collapse
Affiliation(s)
- Alexander Roesch
- Department of Dermatology, University of Regensburg, Regensburg, Germany.
| | | | | | | | | | | | | |
Collapse
|
19
|
Benevolenskaya EV, Murray HL, Branton P, Young RA, Kaelin WG. Binding of pRB to the PHD protein RBP2 promotes cellular differentiation. Mol Cell 2005; 18:623-35. [PMID: 15949438 DOI: 10.1016/j.molcel.2005.05.012] [Citation(s) in RCA: 186] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2004] [Revised: 02/02/2005] [Accepted: 05/16/2005] [Indexed: 12/31/2022]
Abstract
pRB can enforce a G1 block by repressing E2F-responsive promoters. It also coactivates certain non-E2F transcription factors and promotes differentiation. Some pRB variants activate transcription and promote differentiation despite impaired E2F binding and transcriptional repression capabilities. We identified RBP2 in a screen for proteins that bind to such pRB variants. RBP2 resembles other chromatin-associated transcriptional regulators and RBP2 binding tracked with pRB's ability to activate transcription and promote differentiation. RBP2 and pRB colocalize and pRB/RBP2 complexes were detected in chromatin isolated from differentiating cells. RBP2 siRNA phenocopied restoration of pRB function in coactivation and differentiation assays, suggesting that pRB prevents RBP2 from repressing genes required for differentiation. In addition, two bromodomain-containing proteins were identified as RBP2 targets that are transcriptionally activated by pRB in an RBP2-dependent manner. Our results suggest that promotion of differentiation by pRB involves neutralization of free RBP2 and transcriptional activation of RBP2 targets linked to euchromatin maintenance.
Collapse
Affiliation(s)
- Elizaveta V Benevolenskaya
- Dana-Farber Cancer Institute and Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
| | | | | | | | | |
Collapse
|
20
|
Russo G, Zamparelli A, Howard CM, Minimo C, Bellan C, Carillo G, Califano L, Leoncini L, Giordano A, Claudio PP. Expression of cell cycle-regulated proteins pRB2/p130, p107, E2F4, p27, and pCNA in salivary gland tumors: prognostic and diagnostic implications. Clin Cancer Res 2005; 11:3265-73. [PMID: 15867222 DOI: 10.1158/1078-0432.ccr-04-2508] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The retinoblastoma family consists of the tumor suppressor nuclear phosphoprotein pRb/p105 and related proteins p107 and pRb2/p130. Recent immunohistochemical studies of the retinoblastoma family of proteins in lung and endometrial cancer and choroidal melanomas show a tight inverse correlation between the histologic grading in the most aggressive tumor types and pRb2/p130 expression. This led us to investigate the role of pRb2/p130 in salivary tumors. We studied the expression of pRb2/p130, p107, E2F4, p27, and PcNA by immunohistochemistry in a panel of 44 salivary gland tumors. We found a direct correlation between the cytoplasmic expression of pRb2/p130 and tumor grading and the presence of metastasis that was highly statistically significant (P < 0.001). Additionally, increased cytoplasmic pRb2/p130 expression was significantly correlated with a decreased probability of survival (P < 0.001). Interestingly, p107 nuclear expression showed a strong direct correlation when compared with the same variables. pRb2/p130 showed the highest percentage of undetectable nuclear levels in the specimens examined and the tightest inverse correlation (P < 0.0001) with both the histologic grading and pCNA expression in malignant salivary tumors. Additionally, E2F4 showed an identical localization pattern as to that of pRb2/p130. These data suggests an important role for pRb2/p130 in the pathogenesis and progression of certain salivary gland cancers.
Collapse
Affiliation(s)
- Giuseppe Russo
- Sbarro Institute for Cancer Research and Molecular Medicine, College of Science and Technology, Temple University, Philadelphia, PA 19122-6099, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Park KK, Deok Ahn J, Lee IK, Magae J, Heintz NH, Kwak JY, Lee YC, Cho YS, Kim HC, Chae YM, Ho Kim Y, Kim CH, Chang YC. Inhibitory effects of novel E2F decoy oligodeoxynucleotides on mesangial cell proliferation by coexpression of E2F/DP. Biochem Biophys Res Commun 2003; 308:689-97. [PMID: 12927774 DOI: 10.1016/s0006-291x(03)01455-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Proliferation of glomerular mesangial cells (MCs) is an important feature of several forms of glomerulonephritis. The transcription factor E2F coordinately regulates expression of genes required for cell proliferation, thereby mediating cell growth control. Here we investigated the role of E2F1 and E2F4 expression, with or without co-expression of DP1 or DP2, on cell proliferation in transiently transfected primary rat MCs. In transfected cells, cell proliferation induced by over-expression of E2F was significantly enhanced by co-expression of DP proteins. Previous studies showed that the transfection of decoy oligodeoxynucleotides (ODNs) corresponding to E2F binding sites inhibits cell proliferation. Here we have developed a Ring-E2F (R-E2F) decoy ODN with a circular dumbbell structure and compared its effects with those of a phosphorothioated E2F decoy (PS-E2F decoy) ODN. The R-E2F decoy ODN showed enhanced stability in the presence of nucleases and sera, and inhibited E2F/DP-dependent promoter activity of cell cycle genes more effectively than the PS-E2F decoy ODN. Transfection of R-E2F decoy ODN resulted in strong inhibition of cell cycle gene expression and MC proliferation. Our data suggest that E2F/DP complexes play a critical role in the MC proliferation and that the R-E2F decoy ODN may be a powerful tool for inhibiting cell proliferation.
Collapse
Affiliation(s)
- Kwan-Kyu Park
- Kidney Institute, Keimyung University School of Medicine, 194, Dongsan-Dong, Jung-Gu, Daegu 700-712, South Korea
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Abstract
Studies of the retinoblastoma gene (Rb) have shown that its protein product (pRb) acts to restrict cell proliferation, inhibit apoptosis, and promote cell differentiation. The frequent mutation of the Rb gene, and the functional inactivation of pRb in tumor cells, have spurred interest in the mechanism of pRb action. Recently, much attention has focused on pRb's role in the regulation of the E2F transcription factor. However, biochemical studies have suggested that E2F is only one of many pRb-targets and, to date, at least 110 cellular proteins have been reported to associate with pRb. The plethora of pRb-binding proteins raises several important questions. How many functions does pRb possess, which of these functions are important for development, and which contribute to tumor suppression? The goal of this review is to summarize the current literature of pRb-associated proteins.
Collapse
Affiliation(s)
- E J Morris
- Laboratory of Molecular Oncology, Massachusetts General Hospital Cancer Center, Charlestown, Massachusetts 02129, USA
| | | |
Collapse
|
23
|
Chan SW, Hong W. Retinoblastoma-binding Protein 2 (Rbp2) Potentiates Nuclear Hormone Receptor-mediated Transcription. J Biol Chem 2001; 276:28402-12. [PMID: 11358960 DOI: 10.1074/jbc.m100313200] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Retinoblastoma-binding protein 2 (Rbp2) was originally identified as a retinoblastoma protein (RB) pocket domain-binding protein. Although Rbp2 has been shown to interact with RB, p107, TATA-binding protein, and T-cell oncogene rhombotin-2, the physiological function of Rbp2 remains unclear. Here we demonstrate that Rbp2 not only binds to nuclear receptors (NRs) but also enhances the transcription mediated by them. Rbp2 interacts with the DNA-binding domains of NRs and potentiates NR-mediated transcription in an AF-2-dependent manner. Both the N-terminal and C-terminal domains of Rbp2 are critical for the transactivation activity of Rbp2 on NRs. The C terminus is the NR-interacting region. In addition, RB functions in maximizing the effect of Rbp2 on the transcription by NRs. These results suggest that Rbp2 is a coregulator of NRs and define a potential role for Rbp2 in NR-mediated transcription.
Collapse
Affiliation(s)
- S W Chan
- Institute of Molecular and Cell Biology, 30 Medical Drive, Singapore 117609, Republic of Singapore
| | | |
Collapse
|
24
|
Gildea JJ, Lopez R, Shearn A. A screen for new trithorax group genes identified little imaginal discs, the Drosophila melanogaster homologue of human retinoblastoma binding protein 2. Genetics 2000; 156:645-63. [PMID: 11014813 PMCID: PMC1461290 DOI: 10.1093/genetics/156.2.645] [Citation(s) in RCA: 163] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The proteins encoded by two groups of conserved genes, the Polycomb and trithorax groups, have been proposed to maintain, at the level of chromatin structure, the expression pattern of homeotic genes during Drosophila development. To identify new members of the trithorax group, we screened a collection of deficiencies for intergenic noncomplementation with a mutation in ash1, a trithorax group gene. Five of the noncomplementing deletions uncover genes previously classified as members of the Polycomb group. This evidence suggests that there are actually three groups of genes that maintain the expression pattern of homeotic genes during Drosophila development. The products of the third group appear to be required to maintain chromatin in both transcriptionally inactive and active states. Six of the noncomplementing deficiencies uncover previously unidentified trithorax group genes. One of these deficiencies removes 25D2-3 to 26B2-5. Within this region, there are two, allelic, lethal P-insertion mutations that identify one of these new trithorax group genes. The gene has been called little imaginal discs based on the phenotype of mutant larvae. The protein encoded by the little imaginal discs gene is the Drosophila homologue of human retinoblastoma binding protein 2.
Collapse
Affiliation(s)
- J J Gildea
- Department of Biology, The Johns Hopkins University, Baltimore, Maryland 21218, USA
| | | | | |
Collapse
|
25
|
Quadbeck-Seeger C, Wanner G, Huber S, Kahmann R, Kämper J. A protein with similarity to the human retinoblastoma binding protein 2 acts specifically as a repressor for genes regulated by the b mating type locus in Ustilago maydis. Mol Microbiol 2000; 38:154-66. [PMID: 11029697 DOI: 10.1046/j.1365-2958.2000.02128.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Pathogenic development in the corn smut fungus Ustilago maydis is controlled by a heterodimer of the two homeodomain proteins bE and bW which are encoded by the b mating type locus. The bE/bW heterodimer is thought to achieve its function as a transcriptional regulator of pathogenicity genes, either directly by binding to cis regulatory sequences or indirectly via a b-dependent regulatory cascade. In a screen for components of the b-dependent regulatory cascade we have isolated Rum1 (regulator U. maydis 1), a protein with similarities to the human retinoblastoma binding protein 2. Deletion of rum1 results in expression of several b regulated genes independently from their activation via the bE/bW heterodimer. rum1 mutant strains remain pathogenic, proliferate in planta, but fail to produce spores. The defect leads to an arrest in spore development at a defined stage before the spore wall is generated. Deduced from the highly conserved domain structure of Rum1 that includes a DNA-binding motif and a region known to facilitate the interaction with histone deacetylases, we propose that Rum1 functions as a transcriptional repressor through the modulation of chromatin structure.
Collapse
Affiliation(s)
- C Quadbeck-Seeger
- Institut für Genetik und Mikrobiologie, Ludwig-Maximilians-Universität München, Maria-Ward-Strasse 1a, D-80638 München, Germany
| | | | | | | | | |
Collapse
|
26
|
Genetic alterations of the retinoblastoma-related gene RB2/p130 identify different pathogenetic mechanisms in and among Burkitt's lymphoma subtypes. THE AMERICAN JOURNAL OF PATHOLOGY 2000; 156:751-60. [PMID: 10702389 PMCID: PMC1876836 DOI: 10.1016/s0002-9440(10)64941-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Alterations of cell cycle-associated genes probably contribute to the pathogenesis of Burkitt's Lymphoma (BL), in addition to c-myc translocation. Mutations disrupting the nuclear localization signal of the retinoblastoma-related gene RB2/p130 have been documented recently in BL cell lines and primary tumors. Given the importance of the RB2/p130 gene in controlling cell growth, mutations of this gene may result in uncontrolled cell proliferation. We tested the expression and genomic organization of the RB2/p130 gene in relation to the proliferative features of a series of BL samples collected from the endemic and sporadic regions, regardless of whether the samples were acquired immune deficiency syndrome (AIDS)-related. The expression of the Rb2/p130, p107, and cell proliferation-related proteins (cyclin A and B) was determined by immunohistochemistry. The structures of exons 19 through 22 of the RB2/p130 gene, encoding for the B domain and C terminus, were analyzed by polymerase chain reaction (PCR) analysis and single-strand conformation polymorphism (SSCP) technique. The direct PCR products were sequenced to identify the actual mutations. Our results suggest that BL is composed of a mixture of molecular types with distinct genetic and phenotypic patterns, probably resulting from different pathogenetic mechanisms. In endemic BL, the RB2/p130 gene is mutated in most of the cases, and the protein is restricted to the cytoplasm. In AIDS-related BL, high levels of nuclear expression of the wild-type pRb2/p130, p107, and cell proliferation-related proteins were detected. This finding is in line with the molecular mechanisms observed in virus-linked oncogenesis. Sporadic BLs were mainly characterized by the low nuclear values of the wild-type pRb2/p130 and, conversely, the high values of p107. The increased cell proliferation due to different alterations of cell growth control by Rb-related proteins may be the first step in lymphomagenesis, during which additional genetic changes, including missense mutations of c-myc, may subsequently occur.
Collapse
|
27
|
Lai A, Marcellus RC, Corbeil HB, Branton PE. RBP1 induces growth arrest by repression of E2F-dependent transcription. Oncogene 1999; 18:2091-100. [PMID: 10321733 DOI: 10.1038/sj.onc.1202520] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Growth arrest and cell cycle progression are regulated by the retinoblastoma tumour suppressor pRB and related proteins p130 and p107 that bind to and inhibit the E2F family of transcription factors. Although the precise mechanism of this inhibition remains to be established, previous studies indicated the presence of transcriptional repression activity in the 'pocket' of RB family members. We show here that RBP1, a known pRB pocket-binding protein, possesses transcriptional repression activity and associates with p130-E2F and pRB-E2F complexes specifically during growth arrest. Overexpression of RBP1 both inhibited E2F-dependent gene expression and suppressed cell growth. Thus repression of E2F-dependent transcription by RBP1 via RB family members may play a central role in inducing growth arrest.
Collapse
Affiliation(s)
- A Lai
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | | | | | | |
Collapse
|
28
|
Yen A, Sturgill R. Hypophosphorylation of the RB protein in S and G2 as well as G1 during growth arrest. Exp Cell Res 1998; 241:324-31. [PMID: 9637774 DOI: 10.1006/excr.1998.4007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The RB tumor suppressor protein is a cell cycle regulator, where hypophosphorylated RB is associated with G1/0 arrest and its cyclin-dependent phosphorylation in G1 allows progression from G1 to S. The present report shows that in human leukemia cells induced to undergo growth arrest with sodium butyrate or DMSO, hypophosphorylation of the RB protein is not G1 restricted and also occurs in S and G2/M cells as well as in G1 cells when growth is inhibited. While all of the RB protein in G1/0 cells is hypophosphorylated, residual cells in S and G2 have significant detectable amounts of hypophosphorylated RB as well as still hyperphosphorylated RB protein. Thus RB hypophosphorylation can be induced in S and G2 as well as the G1 phase. The results show that growth retardation in other than the G1 phase is associated with occurrence of hypophosphorylated RB. RB may thus have a broader capability to inhibit proliferation than just in G1.
Collapse
Affiliation(s)
- A Yen
- Department of Pathology, Cornell University, Ithaca, New York, 14853, USA
| | | |
Collapse
|
29
|
|
30
|
Zhu P, Bowser R. Identification and analysis of the complete cDNA sequence for the human FAC1 gene. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1309:5-8. [PMID: 8950167 DOI: 10.1016/s0167-4781(96)00127-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The complete cDNA sequence for the FAC1 gene has been isolated from human fetal brain. The FAC1 cDNA encodes for a protein of 810 amino acids that contains a putative Zn(2+)-finger binding domain, nuclear transport signals and a charged acidic domain that may function in protein-protein interactions. Identification of the complete cDNA and protein sequence of FAC1 permits further insight into potential functions for this developmentally regulated gene product.
Collapse
Affiliation(s)
- P Zhu
- Division of Neuropathology, University of Pittsburgh, Presbyterian University Hospital, PA 15213, USA
| | | |
Collapse
|
31
|
Magae J, Wu CL, Illenye S, Harlow E, Heintz NH. Nuclear localization of DP and E2F transcription factors by heterodimeric partners and retinoblastoma protein family members. J Cell Sci 1996; 109 ( Pt 7):1717-26. [PMID: 8832394 DOI: 10.1242/jcs.109.7.1717] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
E2F is a family of transcription factors implicated in the regulation of genes required for progression through G1 and entry into the S phase. The transcriptionally active forms of E2F are heterodimers composed of one polypeptide encoded by the E2F gene family and one polypeptide encoded by the DP gene family. The transcriptional activity of E2F/DP heterodimers is influenced by association with the members of the retinoblastoma tumor suppressor protein family (pRb, p107, and p130). Here the intracellular distribution of E2F and DP proteins was investigated in transiently transfected Chinese hamster and human cells. In transfected cells, DP-1 did not accumulate in the nucleus unless it was coexpressed with the heterodimeric partners E2F-1, E2F-2, or E2F-3. Domain mapping experiments showed that regions of E2F-1 and DP-1 that are required for stable association of the two proteins were also required for nuclear localization of DP-1. Unlike E2F-1, -2, and -3, E2F-4 did not accumulate in the nucleus unless it was coexpressed with DP-2, p107 and p130, but not pRb, stimulated nuclear localization of E2F-4, either alone or in combination with DP-2. These results indicate that DP proteins preferentially associate with specific E2F partners, and suggest that the ability of specific E2F/DP heterodimers to localize in the nucleus contributes to the regulation of E2F activity.
Collapse
Affiliation(s)
- J Magae
- Department of Pathology, University of Vermont, Burlington 05405, USA
| | | | | | | | | |
Collapse
|