1
|
Sainz de la Maza D, Hof-Michel S, Phillimore L, Bökel C, Amoyel M. Cell-cycle exit and stem cell differentiation are coupled through regulation of mitochondrial activity in the Drosophila testis. Cell Rep 2022; 39:110774. [PMID: 35545055 PMCID: PMC9350557 DOI: 10.1016/j.celrep.2022.110774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 02/21/2022] [Accepted: 04/12/2022] [Indexed: 11/27/2022] Open
Abstract
Whereas stem and progenitor cells proliferate to maintain tissue homeostasis, fully differentiated cells exit the cell cycle. How cell identity and cell-cycle state are coordinated during differentiation is still poorly understood. The Drosophila testis niche supports germline stem cells and somatic cyst stem cells (CySCs). CySCs give rise to post-mitotic cyst cells, providing a tractable model to study the links between stem cell identity and proliferation. We show that, while cell-cycle progression is required for CySC self-renewal, the E2f1/Dp transcription factor is dispensable for self-renewal but instead must be silenced by the Drosophila retinoblastoma homolog, Rbf, to permit differentiation. Continued E2f1/Dp activity inhibits the expression of genes important for mitochondrial activity. Furthermore, promoting mitochondrial biogenesis rescues the differentiation of CySCs with ectopic E2f1/Dp activity but not their cell-cycle exit. In sum, E2f1/Dp coordinates cell-cycle progression with stem cell identity by regulating the metabolic state of CySCs. CycE is critical for CySC self-renewal E2f/Dp does not act in self-renewal but must be silenced for differentiation E2f/Dp inhibits increases in oxidative metabolism involved in normal differentiation Increased mitochondrial biogenesis rescues differentiation of E2f/Dp-active cells
Collapse
Affiliation(s)
- Diego Sainz de la Maza
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Silvana Hof-Michel
- Department of Developmental Genetics, Philipps University Marburg, Karl-von-Frisch-Str. 8, 35043 Marburg, Germany
| | - Lee Phillimore
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
| | - Christian Bökel
- Department of Developmental Genetics, Philipps University Marburg, Karl-von-Frisch-Str. 8, 35043 Marburg, Germany.
| | - Marc Amoyel
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK.
| |
Collapse
|
2
|
Payankaulam S, Hickey SL, Arnosti DN. Cell cycle expression of polarity genes features Rb targeting of Vang. Cells Dev 2022; 169:203747. [PMID: 34583062 PMCID: PMC8934252 DOI: 10.1016/j.cdev.2021.203747] [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: 03/28/2021] [Revised: 08/28/2021] [Accepted: 09/17/2021] [Indexed: 11/17/2022]
Abstract
Specification of cellular polarity is vital to normal tissue development and function. Pioneering studies in Drosophila and C. elegans have elucidated the composition and dynamics of protein complexes critical for establishment of cell polarity, which is manifest in processes such as cell migration and asymmetric cell division. Conserved throughout metazoans, planar cell polarity (PCP) genes are implicated in disease, including neural tube closure defects associated with mutations in VANGL1/2. PCP protein regulation is well studied; however, relatively little is known about transcriptional regulation of these genes. Our earlier study revealed an unexpected role for the fly Rbf1 retinoblastoma corepressor protein, a regulator of cell cycle genes, in transcriptional regulation of polarity genes. Here we analyze the physiological relevance of the role of E2F/Rbf proteins in the transcription of the key core polarity gene Vang. Targeted mutations to the E2F site within the Vang promoter disrupts binding of E2F/Rbf proteins in vivo, leading to polarity defects in wing hairs. E2F regulation of Vang is supported by the requirement for this motif in a reporter gene. Interestingly, the promoter is repressed by overexpression of E2F1, a transcription factor generally identified as an activator. Consistent with the regulation of this polarity gene by E2F and Rbf factors, expression of Vang and other polarity genes is found to peak in G2/M phase in cells of the embryo and wing imaginal disc, suggesting that cell cycle signals may play a role in regulation of these genes. These findings suggest that the E2F/Rbf complex mechanistically links cell proliferation and polarity.
Collapse
Affiliation(s)
- Sandhya Payankaulam
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Stephanie L Hickey
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA; Department of Computational Mathematics, Science, and Engineering, Michigan State University, East Lansing, MI, USA
| | - David N Arnosti
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA.
| |
Collapse
|
3
|
Mouawad R, Himadewi P, Kadiyala D, Arnosti DN. Selective repression of the Drosophila cyclin B promoter by retinoblastoma and E2F proteins. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194549. [PMID: 32275964 DOI: 10.1016/j.bbagrm.2020.194549] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Revised: 03/27/2020] [Accepted: 04/03/2020] [Indexed: 02/06/2023]
Abstract
The Cyclin B1 gene encodes a G2/M cyclin that is deregulated in various human cancers, however, the transcriptional regulation of this gene is incompletely understood. The E2F and retinoblastoma family of proteins are involved in this gene's regulation, but there is disagreement on which of the E2F and retinoblastoma proteins interact with the promoter to regulate this gene. Here, we dissect the promoter region of the Drosophila CycB gene, and study the role of Rbf and E2F factors in its regulation. This gene exhibits remarkable features that distinguish it from G1/S regulated promoters, such as PCNA. The promoter is comprised of modular elements with dedicated repressor and activator functions, including a segment spanning the first intron that interferes with a 5' activator element. A highly active minimal promoter (-464, +100) is repressed by the Rbf1 retinoblastoma protein, but much more potently repressed by the Rbf2 protein, which has been linked in other studies to control of cell growth genes. Unlike many other cell-cycle genes, which are activated by E2F1 and repressed by E2F2, CycB is potently activated by E2F2, and repressed by E2F1. Although the bulk of Rbf binding is associated with a region 5' of the core promoter, E2F and retinoblastoma proteins functionally interact with the basal promoter region, in part through a conserved E2F site at -80 bp. The specific regulatory requirements of this late cell cycle promoter appear to be linked to the unique activities of E2F and retinoblastoma family members acting on a complex cis-regulatory circuit.
Collapse
Affiliation(s)
- Rima Mouawad
- Graduate Program in Cell and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States of America.
| | - Pamela Himadewi
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States of America
| | - Dhruva Kadiyala
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States of America
| | - David N Arnosti
- Graduate Program in Cell and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States of America; Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, United States of America.
| |
Collapse
|
4
|
Mouawad R, Prasad J, Thorley D, Himadewi P, Kadiyala D, Wilson N, Kapranov P, Arnosti DN. Diversification of Retinoblastoma Protein Function Associated with Cis and Trans Adaptations. Mol Biol Evol 2020; 36:2790-2804. [PMID: 31418797 DOI: 10.1093/molbev/msz187] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Retinoblastoma proteins are eukaryotic transcriptional corepressors that play central roles in cell cycle control, among other functions. Although most metazoan genomes encode a single retinoblastoma protein, gene duplications have occurred at least twice: in the vertebrate lineage, leading to Rb, p107, and p130, and in Drosophila, an ancestral Rbf1 gene and a derived Rbf2 gene. Structurally, Rbf1 resembles p107 and p130, and mutation of the gene is lethal. Rbf2 is more divergent and mutation does not lead to lethality. However, the retention of Rbf2 >60 My in Drosophila points to essential functions, which prior cell-based assays have been unable to elucidate. Here, using genomic approaches, we provide new insights on the function of Rbf2. Strikingly, we show that Rbf2 regulates a set of cell growth-related genes and can antagonize Rbf1 on specific genes. These unique properties have important implications for the fly; Rbf2 mutants show reduced egg laying, and lifespan is reduced in females and males. Structural alterations in conserved regions of Rbf2 gene suggest that it was sub- or neofunctionalized to develop specific regulatory specificity and activity. We define cis-regulatory features of Rbf2 target genes that allow preferential repression by this protein, indicating that it is not a weaker version of Rbf1 as previously thought. The specialization of retinoblastoma function in Drosophila may reflect a parallel evolution found in vertebrates, and raises the possibility that cell growth control is equally important to cell cycle function for this conserved family of transcriptional corepressors.
Collapse
Affiliation(s)
- Rima Mouawad
- Graduate Program in Cell and Molecular Biology, Michigan State University, East Lansing, MI
| | - Jaideep Prasad
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI
| | - Dominic Thorley
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI
| | - Pamela Himadewi
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI
| | - Dhruva Kadiyala
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI
| | - Nathan Wilson
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI
| | - Philipp Kapranov
- Institute of Genomics, School of Biomedical Sciences, Huaqiao University, Xiamen, China
| | - David N Arnosti
- Graduate Program in Cell and Molecular Biology, Michigan State University, East Lansing, MI.,Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI
| |
Collapse
|
5
|
Lin HY, Chen JC, Fang SC. A Protoplast Transient Expression System to Enable Molecular, Cellular, and Functional Studies in Phalaenopsis orchids. FRONTIERS IN PLANT SCIENCE 2018; 9:843. [PMID: 29988409 PMCID: PMC6024019 DOI: 10.3389/fpls.2018.00843] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 05/30/2018] [Indexed: 05/24/2023]
Abstract
The enigmatic nature of the specialized developmental programs of orchids has fascinated plant biologists for centuries. The recent releases of orchid genomes indicate that orchids possess new gene families and family expansions and contractions to regulate a diverse suite of developmental processes. However, the extremely long orchid life cycle and lack of molecular toolkit have hampered the advancement of orchid biology research. To overcome the technical difficulties and establish a platform for rapid gene regulation studies, in this study, we developed an efficient protoplast isolation and transient expression system for Phalaenopsis aphrodite. This protocol was successfully applied to protein subcellular localization and protein-protein interaction studies. Moreover, it was confirmed to be useful in delineating the PaE2F/PaDP-dependent cell cycle pathway and studying auxin response. In summary, the established orchid protoplast transient expression system provides a means to functionally characterize orchid genes at the molecular level allowing assessment of transcriptome responses to transgene expression and widening the scope of molecular studies in orchids.
Collapse
Affiliation(s)
- Hsiang-Yin Lin
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan, Taiwan
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan
| | - Jhun-Chen Chen
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan, Taiwan
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan
| | - Su-Chiung Fang
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan, Taiwan
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan
| |
Collapse
|
6
|
Quantitative Cell Cycle Analysis Based on an Endogenous All-in-One Reporter for Cell Tracking and Classification. Cell Rep 2018; 19:1953-1966. [PMID: 28564611 PMCID: PMC5464964 DOI: 10.1016/j.celrep.2017.05.022] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/12/2017] [Accepted: 05/04/2017] [Indexed: 12/23/2022] Open
Abstract
Cell cycle kinetics are crucial to cell fate decisions. Although live imaging has provided extensive insights into this relationship at the single-cell level, the limited number of fluorescent markers that can be used in a single experiment has hindered efforts to link the dynamics of individual proteins responsible for decision making directly to cell cycle progression. Here, we present fluorescently tagged endogenous proliferating cell nuclear antigen (PCNA) as an all-in-one cell cycle reporter that allows simultaneous analysis of cell cycle progression, including the transition into quiescence, and the dynamics of individual fate determinants. We also provide an image analysis pipeline for automated segmentation, tracking, and classification of all cell cycle phases. Combining the all-in-one reporter with labeled endogenous cyclin D1 and p21 as prime examples of cell-cycle-regulated fate determinants, we show how cell cycle and quantitative protein dynamics can be simultaneously extracted to gain insights into G1 phase regulation and responses to perturbations. Endogenous mRuby-PCNA as an all-in-one cell cycle reporter Automated image analysis pipeline to segment, track, and classify based on PCNA Quantitative analysis of cyclin oscillations during a complete cell cycle Cyclin D1 maintains G1 phase and prevents the transition into quiescence
Collapse
|
7
|
Nemoto A, Saida S, Kato I, Kikuchi J, Furukawa Y, Maeda Y, Akahane K, Honna-Oshiro H, Goi K, Kagami K, Kimura S, Sato Y, Okabe S, Niwa A, Watanabe K, Nakahata T, Heike T, Sugita K, Inukai T. Specific Antileukemic Activity of PD0332991, a CDK4/6 Inhibitor, against Philadelphia Chromosome-Positive Lymphoid Leukemia. Mol Cancer Ther 2015; 15:94-105. [PMID: 26637365 DOI: 10.1158/1535-7163.mct-14-1065] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 09/29/2015] [Indexed: 11/16/2022]
Abstract
S-phase progression of the cell cycle is accelerated in tumors through various genetic abnormalities, and, thus, pharmacologic inhibition of altered cell-cycle progression would be an effective strategy to control tumors. In the current study, we analyzed the antileukemic activity of three available small molecules targeting CDK4/CDK6 against lymphoid crisis of chronic myeloid leukemia (CML-LC) and Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph(+) ALL), and found that all three molecules showed specific activities against leukemic cell lines derived from CML-LC and Ph(+) ALL. In particular, PD0332991 exhibited extremely high antileukemic activity against CML-LC and Ph(+) ALL cell lines in the nanomolar range by the induction of G0-G1 arrest and partially cell death through dephosphorylation of pRb and downregulation of the genes that are involved in S-phase transition. As an underlying mechanism for favorable sensitivity to the small molecules targeting CDK4/CDK6, cell-cycle progression of Ph(+) lymphoid leukemia cells was regulated by transcriptional and posttranscriptional modulation of CDK4 as well as Cyclin D2 gene expression under the control of BCR-ABL probably through the PI3K pathway. Consistently, the gene expression level of Cyclin D2 in Ph(+) lymphoid leukemia cells was significantly higher than that in Ph(-) lymphoid leukemia cells. Of note, three Ph(+) ALL cell lines having the T315I mutation also showed sensitivity to PD0332991. In a xenograft model, PD0332991, but not imatinib, suppressed dissemination of Ph(+) ALL having the T315I mutation and prolonged survival, demonstrating that this reagent would be a new therapeutic modality for relapsed CML-LC and Ph(+) ALL patients after treatment with tyrosine kinase inhibitors.
Collapse
Affiliation(s)
- Atsushi Nemoto
- Department of Pediatrics, School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Satoshi Saida
- Department of Pediatrics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Itaru Kato
- Department of Pediatrics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Jiro Kikuchi
- Stem Cell Regulation, Center for Molecular Medicine, Jichi Medical School, Tochigi, Japan
| | - Yusuke Furukawa
- Stem Cell Regulation, Center for Molecular Medicine, Jichi Medical School, Tochigi, Japan
| | - Yasuhiro Maeda
- Department of Hematology, National Hospital Organization, Osaka Minami Medical Center, Osaka, Japan
| | - Koshi Akahane
- Department of Pediatrics, School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Hiroko Honna-Oshiro
- Department of Pediatrics, School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Kumiko Goi
- Department of Pediatrics, School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Keiko Kagami
- Department of Pediatrics, School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Shinya Kimura
- Division of Hematology, Respiratory Medicine and Oncology, Department of Internal Medicine, Faculty of Medicine, Saga University, Saga, Japan
| | - Yuko Sato
- Adult Nursing, The Japanese Red Cross College of Nursing, Tokyo, Japan
| | - Seiichi Okabe
- Department of Hematology, Tokyo Medical University, Tokyo, Japan
| | - Akira Niwa
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan
| | - Kenichiro Watanabe
- Department of Pediatrics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Tatsutoshi Nakahata
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan
| | - Toshio Heike
- Department of Pediatrics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Kanji Sugita
- Department of Pediatrics, School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Takeshi Inukai
- Department of Pediatrics, School of Medicine, University of Yamanashi, Yamanashi, Japan.
| |
Collapse
|
8
|
The Hippo pathway as a target of the Drosophila DRE/DREF transcriptional regulatory pathway. Sci Rep 2014; 4:7196. [PMID: 25424907 PMCID: PMC4244634 DOI: 10.1038/srep07196] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 11/04/2014] [Indexed: 01/08/2023] Open
Abstract
The DRE/DREF transcriptional regulatory system has been demonstrated to activate a wide variety of genes with various functions. In Drosophila, the Hippo pathway is known to suppress cell proliferation by inducing apoptosis and cell cycle arrest through inactivation of Yorkie, a transcription co-activator. In the present study, we found that half dose reduction of the hippo (hpo) gene induces ectopic DNA synthesis in eye discs that is suppressed by overexpression of DREF. Half reduction of the hpo gene dose reduced apoptosis in DREF-overexpressing flies. Consistent with these observations, overexpression of DREF increased the levels of hpo and phosphorylated Yorkie in eye discs. Interestingly, the diap1-lacZ reporter was seen to be significantly decreased by overexpression of DREF. Luciferase reporter assays in cultured S2 cells revealed that one of two DREs identified in the hpo gene promoter region was responsible for promoter activity in S2 cells. Furthermore, endogenous hpo mRNA was reduced in DREF knockdown S2 cells, and chromatin immnunoprecipitation assays with anti-DREF antibodies proved that DREF binds specifically to the hpo gene promoter region containing DREs in vivo. Together, these results indicate that the DRE/DREF pathway is required for transcriptional activation of the hpo gene to positively control Hippo pathways.
Collapse
|
9
|
White spot syndrome virus IE1 and WSV056 modulate the G1/S transition by binding to the host retinoblastoma protein. J Virol 2013; 87:12576-82. [PMID: 24027329 DOI: 10.1128/jvi.01551-13] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
DNA viruses often target cellular proteins to modulate host cell cycles and facilitate viral genome replication. However, whether proliferation of white spot syndrome virus (WSSV) requires regulation of the host cell cycle remains unclear. In the present study, we show that two WSSV paralogs, IE1 and WSV056, can interact with Litopenaeus vannamei retinoblastoma (Rb)-like protein (lv-RBL) through the conserved LxCxE motif. Further investigation revealed that IE1 and WSV056 could also bind to Drosophila retinoblastoma family protein 1 (RBF1) in a manner similar to how they bind to lv-RBL. Using the Drosophila RBF-E2F pathway as a model system, we demonstrated that both IE1 and WSV056 could sequester RBF1 from Drosophila E2F transcription factor 1 (E2F1) and subsequently activate E2F1 to stimulate the G1/S transition. Our findings provide the first evidence that WSSV may regulate cell cycle progression by targeting the Rb-E2F pathway.
Collapse
|
10
|
Kawamori A, Shimaji K, Yamaguchi M. Control of e2f1 and PCNA by Drosophila transcription factor DREF. Genesis 2013; 51:741-50. [PMID: 23907762 DOI: 10.1002/dvg.22419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 07/19/2013] [Accepted: 07/24/2013] [Indexed: 12/26/2022]
Abstract
DREF (DNA replication-related element-binding factor), a zinc finger type transcription factor required for proper cell cycle progression in both mitotic and endocycling cells, is a positive regulator of E2F1, an important transcription factor which regulates genes related to the S-phase of the cell cycle. DREF and E2F1 regulate similar sets of replication-related genes, including proliferating cell nuclear antigen (PCNA), and play roles in the G1 to S phase transition. However, the relationships between dref and e2f1 or PCNA during development are poorly understood. Here, we provided evidence for novel control of e2f1 and PCNA involving DREF in endocycling cells. Somatic clone analysis demonstrated that dref knockdown stabilized E2F1 expression at posttranscriptional levels in endocycling salivary gland cells. Similarly, PCNA expression was up-regulated in the endocycling salivary gland cells. Genetic interaction analysis indicated that the endoreplication defects are partly caused via possible enhancement of E2F1 activity. From these results and previous reports, we conclude that regulation of e2f1 and PCNA by DREF in vivo is complex and the regulation mechanism may differ with the tissue and/or positions in the tissue.
Collapse
Affiliation(s)
- Akihito Kawamori
- Department of Applied Biology and Insect Biomedical Research Center, Kyoto Institute of Technology, Sakyo-ku, Kyoto, Japan
| | | | | |
Collapse
|
11
|
O'Keefe DD, Thomas SR, Bolin K, Griggs E, Edgar BA, Buttitta LA. Combinatorial control of temporal gene expression in the Drosophila wing by enhancers and core promoters. BMC Genomics 2012; 13:498. [PMID: 22992320 PMCID: PMC3641971 DOI: 10.1186/1471-2164-13-498] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 09/13/2012] [Indexed: 12/20/2022] Open
Abstract
Background The transformation of a developing epithelium into an adult structure is a complex process, which often involves coordinated changes in cell proliferation, metabolism, adhesion, and shape. To identify genetic mechanisms that control epithelial differentiation, we analyzed the temporal patterns of gene expression during metamorphosis of the Drosophila wing. Results We found that a striking number of genes, approximately 50% of the Drosophila transcriptome, exhibited changes in expression during a time course of wing development. While cis-acting enhancer sequences clearly correlated with these changes, a stronger correlation was discovered between core-promoter types and the dynamic patterns of gene expression within this differentiating tissue. In support of the hypothesis that core-promoter type influences the dynamics of expression, expression levels of several TATA-box binding protein associated factors (TAFs) and other core promoter-associated components changed during this developmental time course, and a testes-specific TAF (tTAF) played a critical role in timing cellular differentiation within the wing. Conclusions Our results suggest that the combinatorial control of gene expression via cis-acting enhancer sequences and core-promoter types, determine the complex changes in gene expression that drive morphogenesis and terminal differentiation of the Drosophila wing epithelium.
Collapse
Affiliation(s)
- David D O'Keefe
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | | | | | | | | | | |
Collapse
|
12
|
Sloan RS, Swanson CI, Gavilano L, Smith KN, Malek PY, Snow-Smith M, Duronio RJ, Key SCS. Characterization of null and hypomorphic alleles of the Drosophila l(2)dtl/cdt2 gene: Larval lethality and male fertility. Fly (Austin) 2012; 6:173-83. [PMID: 22722696 DOI: 10.4161/fly.20247] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The Drosophila lethal(2)denticleless (l(2)dtl) gene was originally reported as essential for embryogenesis and formation of the rows of tiny hairs on the larval ventral cuticle known as denticle belts. It is now well-established that l(2)dtl (also called cdt2) encodes a subunit of a Cullin 4-based E3 ubiquitin ligase complex that targets a number of key cell cycle regulatory proteins, including p21, Cdt1, E2F1 and Set8, to prevent replication defects and maintain cell cycle control. To investigate the role of l(2)dtl/cdt2 during development, we characterized existing l(2)dtl/cdt2 mutants and generated new deletion alleles, using P-element excision mutagenesis. Surprisingly, homozygous l(2)dtl/cdt2 mutant embryos developed beyond embryogenesis, had intact denticle belts, and lacked an observable embryonic replication defect. These mutants died during larval stages, affirming that loss of l(2)dtl/cdt2 function is lethal. Our data show that L(2)dtl/Cdt2 is maternally deposited, remains nuclear throughout the cell cycle, and has a previously unreported, elevated expression in the developing gonads. We also find that E2f1 regulates l(2)dtl/cdt2 expression during embryogenesis, possibly via several highly conserved putative E2f1 binding sites near the l(2)dtl/cdt2 promoter. Finally, hypomorphic allele combinations of the l(2)dtl/cdt2 gene result in a novel phenotype: viable, low-fertility males. We conclude that "denticleless" is a misnomer, but that l(2)dtl/cdt2 is an essential gene for Drosophila development.
Collapse
Affiliation(s)
- Roketa S Sloan
- Department of Biology, North Carolina Central University, Durham, NC USA
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Nicolay BN, Bayarmagnai B, Islam ABMMK, Lopez-Bigas N, Frolov MV. Cooperation between dE2F1 and Yki/Sd defines a distinct transcriptional program necessary to bypass cell cycle exit. Genes Dev 2011; 25:323-35. [PMID: 21325133 DOI: 10.1101/gad.1999211] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The Hippo signaling pathway regulates organ size homeostasis, while its inactivation leads to severe hyperplasia in flies and mammals. The transcriptional coactivator Yorkie (Yki) mediates transcriptional output of the Hippo signaling. Yki lacks a DNA-binding domain and is recruited to its target promoters as a complex with DNA-binding proteins such as Scalloped (Sd). In spite of recent progress, an open question in the field is the mechanism through which the Yki/Sd transcriptional signature is defined. Here, we report that Yki/Sd synergizes with and requires the transcription factor dE2F1 to induce a specific transcriptional program necessary to bypass the cell cycle exit. We show that Yki/Sd and dE2F1 bind directly to the promoters of the Yki/Sd-dE2F1 shared target genes and activate their expression in a strong cooperative manner. Consistently, RBF, a negative regulator of dE2F1, negates this synergy and limits the overall level of expression of the Yki/Sd-dE2F1 target genes. Significantly, dE2F1 is needed for Yki/Sd-dependent full activation of these target genes, and a de2f1 mutation strongly blocks yki-induced proliferation in vivo. Thus, the Yki transcriptional program is determined through functional interactions with other transcription factors directly at target promoters. We suggest that such functional interactions would influence Yki activity and help diversify the transcriptional output of the Hippo pathway.
Collapse
Affiliation(s)
- Brandon N Nicolay
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois 60607, USA
| | | | | | | | | |
Collapse
|
14
|
Mammalian MCM loading in late-G(1) coincides with Rb hyperphosphorylation and the transition to post-transcriptional control of progression into S-phase. PLoS One 2009; 4:e5462. [PMID: 19421323 PMCID: PMC2674209 DOI: 10.1371/journal.pone.0005462] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Accepted: 04/15/2009] [Indexed: 01/19/2023] Open
Abstract
Background Control of the onset of DNA synthesis in mammalian cells requires the coordinated assembly and activation of the pre-Replication Complex. In order to understand the regulatory events controlling preRC dynamics, we have investigated how the timing of preRC assembly relates temporally to other biochemical events governing progress into S-phase. Methodology/Principal Finding In murine and Chinese hamster (CHO) cells released from quiescence, the loading of the replicative MCM helicase onto chromatin occurs in the final 3–4 hrs of G1. Cdc45 and PCNA, both of which are required for G1-S transit, bind to chromatin at the G1-S transition or even earlier in G1, when MCMs load. An RNA polymerase II inhibitor (DRB) was added to synchronized murine keratinocytes to show that they are no longer dependent on new mRNA synthesis 3–4 hrs prior to S-phase entry, which is also true for CHO and human cells. Further, CHO cells can progress into S-phase on time, and complete S-phase, under conditions where new mRNA synthesis is significantly compromised, and such mRNA suppression causes no adverse effects on preRC dynamics prior to, or during, S-phase progression. Even more intriguing, hyperphosphorylation of Rb coincides with the start of MCM loading and, paradoxically, with the time in late-G1 when de novo mRNA synthesis is no longer rate limiting for progression into S-phase. Conclusions/Significance MCM, Cdc45, and PCNA loading, and the subsequent transit through G1-S, do not depend on concurrent new mRNA synthesis. These results indicate that mammalian cells pass through a distinct transition in late-G1 at which time Rb becomes hyperphosphorylated and MCM loading commences, but that after this transition the control of MCM, Cdc45, and PCNA loading and the onset of DNA replication are regulated at the post-transcriptional level.
Collapse
|
15
|
Identification of the Drosophila Mes4 gene as a novel target of the transcription factor DREF. Exp Cell Res 2009; 315:1403-14. [DOI: 10.1016/j.yexcr.2008.12.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 12/18/2008] [Accepted: 12/18/2008] [Indexed: 12/16/2022]
|
16
|
Tanaka-Matakatsu M, Xu J, Cheng L, Du W. Regulation of apoptosis of rbf mutant cells during Drosophila development. Dev Biol 2008; 326:347-56. [PMID: 19100727 DOI: 10.1016/j.ydbio.2008.11.035] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Accepted: 11/19/2008] [Indexed: 12/19/2022]
Abstract
Inactivation of the retinoblastoma gene Rb leads to defects in cell proliferation, differentiation, or apoptosis, depending on specific cell or tissue types. To gain insights into the genes that can modulate the consequences of Rb inactivation, we carried out a genetic screen in Drosophila to identify mutations that affected apoptosis induced by inactivation of the Retinoblastoma-family protein (rbf) and identified a mutation that blocked apoptosis induced by rbf. We found this mutation to be a new allele of head involution defective (hid) and showed that hid expression is deregulated in rbf mutant cells in larval imaginal discs. We identified an enhancer that regulates hid expression in response to developmental cues as well as to radiation and demonstrated that this hid enhancer is directly repressed by RBF through an E2F binding site. These observations indicate that apoptosis of rbf mutant cells is mediated by an upregulation of hid. Finally, we showed that bantam, a miRNA that regulates hid translation, is expressed in the interommatidial cells in the larval eye discs and modulates the survival of rbf mutant cells.
Collapse
Affiliation(s)
- Miho Tanaka-Matakatsu
- Ben May Department for Cancer Research, the University of Chicago, Chicago, IL 60637, USA
| | | | | | | |
Collapse
|
17
|
The DRE/DREF transcriptional regulatory system: a master key for cell proliferation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2007; 1779:81-9. [PMID: 18155677 DOI: 10.1016/j.bbagrm.2007.11.011] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Revised: 11/27/2007] [Accepted: 11/27/2007] [Indexed: 11/23/2022]
Abstract
The coordinate expression of many cell proliferation-related genes is required for the cellular shift from the resting state into the proliferating state. One regulatory factor involved in this process, the transcription regulatory factor named DREF (DNA replication-related element-binding factor) was discovered in Drosophila and later found to have orthologues in other species including human. Drosophila DREF is a homo-dimer of a polypeptide of 709 amino acid residues, and shares about 22% identity in its amino acid sequence with the human homolog of 694 amino acid residues. The Drosophila DREF homo-dimer binds specifically to the DRE sequence (5'-TATCGATA) in the promoters of many DNA replication/ cell proliferation-related genes to activate their transcription, and the N-terminal region of DREF carries a domain for specific DRE-binding and homo-dimer formation. Ectopic expression of DREF in eye imaginal discs induces abnormal DNA synthesis, apoptosis and failure to differentiate. Conversely, expression of the dominant negative N-terminal region in larval salivary glands reduces endo-replication. Furthermore, RNA interference-mediated knockdown of DREF in vivo demonstrated its requirement for normal progression through the cell cycle and consequently for growth of imaginal discs and the endoreplicating organs. Both Drosophila and human DREF's interact genetically and physically with regulatory factors related to chromatin structures, suggesting that DREF activates the expression of proliferation-related genes through modification of the 3-D conformation of DNA. A search of the Drosophila genome database identified about 150 genes carrying DRE sequences in their promoter regions, many of which are related to reactions required for cell proliferation such as DNA replication, transcriptional regulation, cell cycle regulation, growth signal transduction and protein metabolism. Thus, DREF appears to be a master key-like factor for cell proliferation. Several differentiation-related transcription factors containing homeodomains down-regulate the function or expression of DREF by distinct mechanisms, suggesting a differentiation-coupled repression of cell proliferation via the DRE/DREF system.
Collapse
|
18
|
Ida H, Yoshida H, Nakamura K, Yamaguchi M. Identification of the Drosophila eIF4A gene as a target of the DREF transcription factor. Exp Cell Res 2007; 313:4208-20. [PMID: 17888422 DOI: 10.1016/j.yexcr.2007.08.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Revised: 08/17/2007] [Accepted: 08/17/2007] [Indexed: 01/31/2023]
Abstract
The DNA replication-related element-binding factor (DREF) regulates cell proliferation-related gene expression in Drosophila. We have carried out a genetic screening, taking advantage of the rough eye phenotype of transgenic flies that express full-length DREF in the eye imaginal discs and identified the eukaryotic initiation factor 4A (eIF4A) gene as a dominant suppressor of the DREF-induced rough eye phenotype. The eIF4A gene was here found to carry three DRE sequences, DRE1 (-40 to -47), DRE2 (-48 to -55), and DRE3 (-267 to -274) in its promoter region, these all being important for the eIF4A gene promoter activity in cultured Drosophila Kc cells and in living flies. Knockdown of DREF in Drosophila S2 cells decreased the eIF4A mRNA level and the eIF4A gene promoter activity. Furthermore, specific binding of DREF to genomic regions containing DRE sequences was demonstrated by chromatin immunoprecipitation assays using anti-DREF antibodies. Band mobility shift assays using Kc cell nuclear extracts revealed that DREF could bind to DRE1 and DRE3 sequences in the eIF4A gene promoter in vitro, but not to the DRE2 sequence. The results suggest that the eIF4A gene is under the control of the DREF pathway and DREF is therefore involved in the regulation of protein synthesis.
Collapse
Affiliation(s)
- Hiroyuki Ida
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | | | | | | |
Collapse
|
19
|
Morris EJ, Michaud WA, Ji JY, Moon NS, Rocco JW, Dyson NJ. Functional identification of Api5 as a suppressor of E2F-dependent apoptosis in vivo. PLoS Genet 2006; 2:e196. [PMID: 17112319 PMCID: PMC1636698 DOI: 10.1371/journal.pgen.0020196] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Accepted: 10/03/2006] [Indexed: 11/24/2022] Open
Abstract
Retinoblastoma protein and E2-promoter binding factor (E2F) family members are important regulators of G1-S phase progression. Deregulated E2F also sensitizes cells to apoptosis, but this aspect of E2F function is poorly understood. Studies of E2F-induced apoptosis have mostly been carried out in tissue culture cells, and the analysis of the factors that are important for this process has been restricted to the testing of a few candidate genes. Using Drosophila as a model system, we have generated tools that allow genetic modifiers of E2F-dependent apoptosis to be identified in vivo and developed assays that allow effects on E2F-induced apoptosis to be studied in cultured cells. Genetic interactions show that dE2F1-dependent apoptosis in vivo involves dArk/Apaf1 apoptosome-dependent activation of both initiator and effector caspases and is sensitive to levels of Drosophila inhibitor of apoptosis-1 (dIAP1). Using these approaches, we report the surprising finding that apoptosis inhibitor-5/antiapoptosis clone-11 (Api5/Aac11) is a critical determinant of dE2F1-induced apoptosis in vivo and in vitro. This functional interaction occurs in multiple tissues, is specific to E2F-induced apoptosis, and is conserved from flies to humans. Interestingly, Api5/Aac11 acts downstream of E2F and suppresses E2F-dependent apoptosis without generally blocking E2F-dependent transcription. Api5/Aac11 expression is often upregulated in tumor cells, particularly in metastatic cells. We find that depletion of Api5 is tumor cell lethal. The strong genetic interaction between E2F and Api5/Aac11 suggests that elevated levels of Api5 may be selected during tumorigenesis to allow cells with deregulated E2F activity to survive under suboptimal conditions. Therefore, inhibition of Api5 function might offer a possible mechanism for antitumor exploitation. The retinoblastoma protein (pRB) was the first human tumor suppressor to be described, and it works by limiting the activity of the E2F transcription factor. The pRB pathway is inactivated in most forms of cancer, and, accordingly, most tumor cells have deregulated E2F. Uncontrolled E2F drives cell proliferation, but it also sensitizes cells to die (apoptosis). E2F-induced apoptosis is not well understood, but it affects the development of cancer and, potentially, could be exploited for cancer treatment. To date, however, there have been very few studies of E2F-induced apoptosis in animal models. The authors describe a series of genetic tools that allow systematic studies of E2F-induced apoptosis in Drosophila. As validation, this approach identified some known regulators of E2F-dependent apoptosis and also identified Api5, a little-studied gene that had not previously been linked to E2F, as a potent suppressor of E2F-induced cell death. The effects of Api5 on E2F occur in several different tissues and are conserved from flies to humans. This last point is significant since Api5 is upregulated in cancer cells. The discovery of the E2F–Api5 interaction demonstrates that important modulators of E2F-induced apoptosis are waiting to be discovered and that they can be found using Drosophila.
Collapse
Affiliation(s)
- Erick J Morris
- Massachusetts General Hospital Cancer Center, Laboratory of Molecular Oncology, Charlestown, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - William A Michaud
- Massachusetts General Hospital Cancer Center, Laboratory of Molecular Oncology, Charlestown, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
- Division of Surgical Oncology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States of America
| | - Jun-Yuan Ji
- Massachusetts General Hospital Cancer Center, Laboratory of Molecular Oncology, Charlestown, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - Nam-Sung Moon
- Massachusetts General Hospital Cancer Center, Laboratory of Molecular Oncology, Charlestown, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
| | - James W Rocco
- Massachusetts General Hospital Cancer Center, Laboratory of Molecular Oncology, Charlestown, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
- Division of Surgical Oncology, Massachusetts General Hospital, Boston, Massachusetts, United States of America
- Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States of America
| | - Nicholas J Dyson
- Massachusetts General Hospital Cancer Center, Laboratory of Molecular Oncology, Charlestown, Massachusetts, United States of America
- Harvard Medical School, Boston, Massachusetts, United States of America
- * To whom correspondence should be addressed. E-mail:
| |
Collapse
|
20
|
Okudaira K, Ohno K, Yoshida H, Asano M, Hirose F, Yamaguchi M. Transcriptional regulation of the Drosophila orc2 gene by the DREF pathway. ACTA ACUST UNITED AC 2006; 1732:23-30. [PMID: 16343659 DOI: 10.1016/j.bbaexp.2005.10.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2005] [Revised: 10/25/2005] [Accepted: 10/27/2005] [Indexed: 11/18/2022]
Abstract
DNA replication-related element (DRE) and the DRE-binding factor (DREF) play an important role in regulating DNA replication-related genes such as PCNA and DNA polymerase alpha in Drosophila. We have previously reported that overexpression of DREF in developing eye imaginal discs induced ectopic DNA synthesis and apoptosis, which results in rough eyes. To identify genetic interactants with the DREF gene, we have carried out a screen for modifiers of the rough eye phenotype. One of the suppressor genes identified was the Drosophila orc2 gene. A search for known transcription factor recognition sites revealed that the orc2 gene contains three DREs, named DRE1 (+14 to +21), DRE2 (-205 to -198), and DRE3 (-709 to -702). Band mobility shift analysis using Kc cell nuclear extracts detected the specific complex formed between DREF and the DRE1 or DRE2. Specific binding of DREF to genomic region containing the DRE1 or DRE2 was further demonstrated by chromatin immunoprecipitation assays, suggesting that these are the genuine complexes formed in vivo. The luciferase assay in Kc cells indicated that the DRE sites in the orc2 promoter are involved in a transcriptional regulation of the orc2 gene. The results, taken together, demonstrate that the orc2 gene is under the control of DREF pathway.
Collapse
Affiliation(s)
- Koji Okudaira
- Department of Applied Biology, Faculty of Textile Science, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | | | | | | | | | | |
Collapse
|
21
|
Yoshida H, Kwon E, Hirose F, Otsuki K, Yamada M, Yamaguchi M. DREF is required for EGFR signalling during Drosophila wing vein development. Genes Cells 2005; 9:935-44. [PMID: 15461664 DOI: 10.1111/j.1365-2443.2004.00775.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The DNA replication-related element binding factor (DREF) has been suggested as being involved in regulation of DNA replication- and proliferation-related genes in Drosophila. Recently, by searching the Drosophila genome database, we also found DRE-like sequences in the 5'-flanking regions of many genes with other functions. In addition, immunostaining of polytene chromosomes with an anti-DREF monoclonal antibody revealed that DREF can bind to a hundred regions of polytene chromosomes, suggesting regulation of multiple genes and multiple roles in vivo. When we over-expressed DREF protein or inverted repeat RNA of the DREF gene in wing imaginal discs using the GAL4-UAS targeted expression system in Drosophila, the results were veins of increased width and a loss of veins, respectively. With DREF over-expression, Rolled, a Drosophila MAPK homologue, was ectopically activated. Furthermore, half reduction of the D-raf gene dose suppressed this DREF-induced vein of increased width phenotype. In addition, when DREF transcripts were reduced by introducing double-stranded RNA of the DREF gene into S2 cells, the D-raf gene promoter activity was diminished to 4%. These data indicate that DREF is involved in regulation of vein formation through the activation of EGFR signalling in the Drosophila wing imaginal discs.
Collapse
Affiliation(s)
- Hideki Yoshida
- Venture Laboratory, Kyoto Institute of Technology, Sakyo-ku, Kyoto, Japan
| | | | | | | | | | | |
Collapse
|
22
|
Otsuki K, Hayashi Y, Kato M, Yoshida H, Yamaguchi M. Characterization of dRFX2, a novel RFX family protein in Drosophila. Nucleic Acids Res 2004; 32:5636-48. [PMID: 15494451 PMCID: PMC524303 DOI: 10.1093/nar/gkh895] [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] [Received: 07/22/2004] [Revised: 09/29/2004] [Accepted: 09/29/2004] [Indexed: 11/13/2022] Open
Abstract
A transcriptional regulatory element was identified in the region between URE (upstream regulatory element) and DRE (DNA replication-related element) in the Drosophila PCNA gene promoter. This element plays an important role in promoter activity in living flies. A yeast one-hybrid screening using this element as a bait allowed isolation of a cDNA encoding a protein which binds to the element in vitro. Nucleotide sequence analyses revealed that the cDNA encodes a novel protein containing a characteristic DNA-binding domain conserved among the regulatory factor X (RFX) family proteins. We termed this protein Drosophila RFX2 (dRFX2) and this element dRFX2 site. To investigate the function of dRFX2 in vivo, we took the strategy of analyzing the dominant negative effects against the endogenous dRFX2. Transgenic flies were established in which expression of HA-dRFX(202-480) carrying the amino acid sequences from 202 to 480 containing the RFX domain (DNA-binding domain) of dRFX2 was targeted to the cells in the eye imaginal discs. In the eye imaginal disc expressing the HA-dRFX(202-480), the G1-S transition and/or the progression of S phase were/was interrupted, and the ectopic apoptosis was induced, though photoreceptor cells differentiated normally. These results indicate that dRFX2 plays a role in G1-S transition and/or in progression of S phase.
Collapse
Affiliation(s)
- Kyoko Otsuki
- Department of Applied Biology, Faculty of Textile Science, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | | | | | | | | |
Collapse
|
23
|
Parakati R, Dimario JX. Repression of fibroblast growth factor receptor 1 gene expression by E2F4 in skeletal muscle cells. Dev Dyn 2004; 232:119-30. [PMID: 15580623 DOI: 10.1002/dvdy.20214] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Fibroblast growth factor receptor 1 (FGFR1) gene expression is positively and negatively regulated during muscle differentiation. We recently reported that FGFR1 gene expression was up-regulated by Sp transcription factors in proliferating myoblasts. However, the mechanism of down-regulation of this gene during differentiation is unknown. We have identified the transcription factor E2F4 as a negative regulator of FGFR1 gene expression. Immunodetection studies revealed that endogenous E2F1 and E2F2 proteins were cytoplasmic in myoblasts and myotubes, whereas E2F4 was abundant in the nuclei of both. Upon overexpression, E2F4 repressed FGFR1 promoter activity in a dose-dependent manner in myoblasts and Drosophila SL2 cells, and mutation of the E2F4 binding site increased FGFR1 promoter activity and reduced E2F4-mediated repression. Gel shift assays detected E2F4 binding to a synthetic FGFR1 E2F4 binding site and chromatin immunoprecipitation assays detected E2F4 binding to the endogenous FGFR1 promoter in proliferating myoblasts and myotubes. The results indicate that FGFR1 promoter activity in skeletal muscle cells is repressed by E2F4.
Collapse
MESH Headings
- Animals
- Binding Sites
- Binding, Competitive
- Blotting, Western
- Cell Line
- Cell Nucleus/metabolism
- Cell Proliferation
- Chick Embryo
- Chromatin Immunoprecipitation
- DNA/metabolism
- DNA-Binding Proteins/metabolism
- DNA-Binding Proteins/physiology
- Dose-Response Relationship, Drug
- Down-Regulation
- Drosophila
- E2F4 Transcription Factor
- Embryonic Development
- Fibroblast Growth Factor 1/biosynthesis
- Fibroblast Growth Factor 1/physiology
- Gene Expression Regulation, Developmental
- Genes, Reporter
- Immunohistochemistry
- Muscle Fibers, Skeletal/metabolism
- Muscle, Skeletal/cytology
- Muscle, Skeletal/embryology
- Muscle, Skeletal/metabolism
- Mutation
- Myoblasts/metabolism
- Plasmids/metabolism
- Promoter Regions, Genetic
- Protein Binding
- Signal Transduction
- Subcellular Fractions/metabolism
- Time Factors
- Transcription Factors/metabolism
- Transcription Factors/physiology
- Transfection
Collapse
Affiliation(s)
- Rajini Parakati
- Department of Cell Biology and Anatomy, Chicago Medical School, North Chicago, Illinois
| | | |
Collapse
|
24
|
Middleton K, Peh W, Southern S, Griffin H, Sotlar K, Nakahara T, El-Sherif A, Morris L, Seth R, Hibma M, Jenkins D, Lambert P, Coleman N, Doorbar J. Organization of human papillomavirus productive cycle during neoplastic progression provides a basis for selection of diagnostic markers. J Virol 2003; 77:10186-201. [PMID: 12970404 PMCID: PMC228472 DOI: 10.1128/jvi.77.19.10186-10201.2003] [Citation(s) in RCA: 165] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The productive cycle of human papillomaviruses (HPVs) can be divided into discrete phases. Cell proliferation and episomal maintenance in the lower epithelial layers are followed by genome amplification and the expression of capsid proteins. These events, which occur in all productive infections, can be distinguished by using antibodies to viral gene products or to surrogate markers of their expression. Here we have compared precancerous lesions caused by HPV type 16 (HPV16) with lesions caused by HPV types that are not generally associated with human cancer. These include HPV2 and HPV11, which are related to HPV16 (supergroup A), as well as HPV1 and HPV65, which are evolutionarily divergent (supergroups E and B). HPV16-induced low-grade squamous intraepithelial lesions (CIN1) are productive infections which resemble those caused by other HPV types. During progression to cancer, however, the activation of late events is delayed, and the thickness of the proliferative compartment is progressively increased. In many HPV16-induced high-grade squamous intraepithelial lesions (CIN3), late events are restricted to small areas close to the epithelial surface. Such heterogeneity in the organization of the productive cycle was seen only in lesions caused by HPV16 and was not apparent when lesions caused by other HPV types were compared. By contrast, the order in which events in the productive cycle were initiated was invariant and did not depend on the infecting HPV type or the severity of disease. The distribution of viral gene products in the infected cervix depends on the extent to which the virus can complete its productive cycle, which in turn reflects the severity of cervical neoplasia. It appears from our work that the presence of such proteins in cells at the epithelial surface allows the severity of the underlying disease to be predicted and that markers of viral gene expression may improve cervical screening.
Collapse
Affiliation(s)
- Kate Middleton
- National Institute for Medical Research, Mill Hill, London
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
25
|
Delanoue R, Legent K, Godefroy N, Flagiello D, Dutriaux A, Vaudin P, Becker JL, Silber J. The Drosophila wing differentiation factor Vestigial–Scalloped is required for cell proliferation and cell survival at the dorso-ventral boundary of the wing imaginal disc. Cell Death Differ 2003; 11:110-22. [PMID: 14526388 DOI: 10.1038/sj.cdd.4401321] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Links between genes involved in development, proliferation and apoptosis have been difficult to establish. In the Drosophila wing disc, the vestigial (vg) and the scalloped (sd) gene products dimerize to form a functional transcription factor. Ectopic expression of vg in other imaginal discs induces outgrowth and wing tissue specification. We investigated the role of the VG-SD dimer in proliferation and showed that vg antagonizes the effect of dacapo, the cyclin-cdk inhibitor. Moreover, ectopic vg drives cell cycle progression and in HeLa cultured cells, the VG-SD dimer induces cell proliferation per se. In Drosophila, ectopic vg induces expression of dE2F1 and its targets dRNR2 and string. In addition vg, but not dE2F1, interacts with and induces expression of dihydrofolate reductase (DHFR). Moreover, a decrease in VG or addition of aminopterin, a specific DHFR inhibitor, shift the dorso-ventral boundary cells of the disc to a cell death sensitive state that is correlated with reaper induction and DIAP1 downregulation. This indicates that vg in interaction with dE2F1 and DHFR is a critical player for both cell proliferation and cell survival in the presumptive wing margin area.
Collapse
Affiliation(s)
- R Delanoue
- Institut Jacques Monod, Tour 43, 2, Place Jussieu, 75251 Paris, France
| | | | | | | | | | | | | | | |
Collapse
|
26
|
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
|
27
|
Ohshima N, Takahashi M, Hirose F. Identification of a human homologue of the DREF transcription factor with a potential role in regulation of the histone H1 gene. J Biol Chem 2003; 278:22928-38. [PMID: 12663651 DOI: 10.1074/jbc.m303109200] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
A human homologue (hDREF/KIAA0785) of Drosophila DREF, a transcriptional regulatory factor required for expression of genes involved in DNA replication and cell proliferation, was identified by BLAST search. Amino acid sequences corresponding to three regions highly conserved between two Drosophila species also proved to be very similar in the hDREF/KIAA0785 polypeptide. A consensus binding sequence (5'-TGTCG(C/T)GA(C/T)A) for hDREF/KIAA0785, determined by the CASTing method, overlapped with that for the Drosophila DREF (5'-TGTCGATA). We found hDREF/KIAA0785 binding sequences in the promoter regions of human genes related to cell proliferation. Analyses using a specific antibody revealed that an hDREF/KIAA0785 binds to the promoter region of the histone H1 gene. Co-transfection experiments with an hDREF/KIAA0785-expressing plasmid and a histone H1 promoter-directed luciferase reporter plasmid in HeLa cells revealed possible activation of the histone H1 promoter. Immunohistochemical analysis demonstrated that hDREF/KIAA0785 is localized in the nuclei. Although the expression level of the factor was found to be low in serum-deprived human normal fibroblasts, the amount was increased by adding serum to cultures and reached a maximum during S phase. RNA interference experiments targeting hDREF/KIAA0785 resulted in inhibition of S phase entry and reduction of histone H1 mRNA in HeLa cells. These results suggest that expression of hDREF/KIAA0785 may have a role in regulation of human genes related to cell proliferation.
Collapse
Affiliation(s)
- Nobuko Ohshima
- Division of Biochemistry, Aichi Cancer Center Research Institute, Chikusa-ku, Nagoya 464-8681, Japan
| | | | | |
Collapse
|
28
|
Li YY, Wang L, Lu CD. An E2F site in the 5'-promoter region contributes to serum-dependent up-regulation of the human proliferating cell nuclear antigen gene. FEBS Lett 2003; 544:112-8. [PMID: 12782299 DOI: 10.1016/s0014-5793(03)00485-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The synthesis of proliferating cell nuclear antigen (PCNA) is strictly regulated during the cell cycle. To investigate the contribution of the promoter region to the up-regulation of human PCNA expression at the onset of S phase, we have examined 17 putative elements with reporter assays in quiescent L-O2 cells and following serum stimulation. The E2F-like sequence 5'-TTCCCCGCAA-3' located at -84 to -75 is required for the serum-induced transactivation. In electrophoretic mobility shift assays, nuclear extracts from asynchronous L-O2 cells exhibit two binding activities toward the -75 E2F oligonucleotide, and the minor band, whose formation could be interfered with by E2F-1 antibody, represents an S phase-specific complex. This is the first demonstration of the E2F site in the human PCNA 5' promoter as a serum-responsive element.
Collapse
Affiliation(s)
- Yuan-Yuan Li
- Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, PR China
| | | | | |
Collapse
|
29
|
Renault AD, Axton JM. Identification of plu genes and cis-acting elements of PCNA in the Drosophila genus using conservation of gene order. Gene 2003; 307:77-86. [PMID: 12706890 DOI: 10.1016/s0378-1119(03)00444-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In Drosophila melanogaster, the cell cycle control gene, plutonium (plu), is located between the PCNA and RpS18 genes at position 56F on chromosome arm 2R. We have used a comparative genomic approach to investigate the evolution of the plu gene and to locate conserved cis-acting elements for plu, RpS18 and PCNA. Using primers within coding regions of PCNA and RpS18, we amplified and sequenced the intervening region from twelve Drosophila species. In each species, this region contains a plu gene resembling the D. melanogaster gene in size and in the number and position of introns. The predicted Plu sequence from the different species demonstrates that the first two ankyrin repeats are conserved. Of the transcriptional control elements of D. melanogaster PCNA, we found that three motifs 5' to the PCNA transcription unit are conserved in Drosophila species.
Collapse
Affiliation(s)
- Andrew D Renault
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | | |
Collapse
|
30
|
Thacker SA, Bonnette PC, Duronio RJ. The contribution of E2F-regulated transcription to Drosophila PCNA gene function. Curr Biol 2003; 13:53-8. [PMID: 12526745 DOI: 10.1016/s0960-9822(02)01400-8] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
E2F proteins control cell cycle progression by predominantly acting as either activators or repressors of transcription. How the antagonizing activities of different E2Fs are integrated by cis-acting control regions into a final transcriptional output in an intact animal is not well understood. E2F function is required for normal development in many species, but it is not completely clear for which genes E2F-regulated transcription provides an essential biological function. To address these questions, we have characterized the control region of the Drosophila PCNA gene. A single E2F binding site within a 100-bp enhancer is necessary and sufficient to direct the correct spatiotemporal program of G1-S-regulated PCNA expression during development. This dynamic program requires both E2F-mediated transcriptional activation and repression, which, in Drosophila, are thought to be carried out by two distinct E2F proteins. Our data suggest that functional antagonism between these different E2F proteins can occur in vivo by competition for the same binding site. An engineered PCNA gene with mutated E2F binding sites supports a low level of expression that can partially rescue the lethality of PCNA null mutants. Thus, E2F regulation of PCNA is dispensable for viability, but is nonetheless important for normal Drosophila development.
Collapse
Affiliation(s)
- Stephen A Thacker
- Program in Molecular Biology, University of North Carolina, 27599, Chapel Hill, NC, USA
| | | | | |
Collapse
|
31
|
Hwang MS, Kim YS, Choi NH, Park JH, Oh EJ, Kwon EJ, Yamaguchi M, Yoo MA. The caudal homeodomain protein activates Drosophila E2F gene expression. Nucleic Acids Res 2002; 30:5029-35. [PMID: 12466526 PMCID: PMC137955 DOI: 10.1093/nar/gkf640] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The Drosophila caudal homeobox gene is required for definition of the anteroposterior axis and for gut development, and CDX1 and CDX2, human homologs, play crucial roles in the regulation of cell proliferation and differentiation in the intestine. Most studies have indicated tumor suppressor functions of Cdx2, with inhibition of proliferation, while the effects of Cdx1 are more controversial. The influence of Drosophila Caudal on cell proliferation is unknown. In this study, we found three potential Caudal binding sequences in the 5'-flanking region of the Drosophila E2F (DE2F) gene and showed by transient transfection assays that they are involved in Caudal transactivation of the dE2F gene promoter. Analyses with transgenic flies carrying an E2F-lacZ fusion gene, with and without mutation in the Caudal binding site, indicated that the Caudal binding sites are required for expression of dE2F in living flies. Caudal-induced E2F expression was also confirmed with a GAL4-UAS system in living flies. In addition, ectopic expression of Caudal with heat-shock promotion induced melanotic tumors in larvae. These results suggest that Caudal is involved in regulation of proliferation through transactivation of the E2F gene in Drosophila.
Collapse
Affiliation(s)
- Mi-Sun Hwang
- Department of Molecular Biology, Pusan National University, Pusan 609-735, Korea
| | | | | | | | | | | | | | | |
Collapse
|
32
|
Stevaux O, Dimova D, Frolov MV, Taylor-Harding B, Morris E, Dyson N. Distinct mechanisms of E2F regulation by Drosophila RBF1 and RBF2. EMBO J 2002; 21:4927-37. [PMID: 12234932 PMCID: PMC126297 DOI: 10.1093/emboj/cdf501] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2002] [Revised: 07/19/2002] [Accepted: 07/31/2002] [Indexed: 11/13/2022] Open
Abstract
RBF1, a Drosophila pRB family homolog, is required for cell cycle arrest and the regulation of E2F-dependent transcription. Here, we describe the properties of RBF2, a second family member. RBF2 represses E2F transcription and is present at E2F-regulated promoters. Analysis of in vivo protein complexes reveals that RBF1 and RBF2 interact with different subsets of E2F proteins. dE2F1, a potent transcriptional activator, is regulated specifically by RBF1. In contrast, RBF2 binds exclusively to dE2F2, a form of E2F that functions as a transcriptional repressor. We find that RBF2-mediated repression requires dE2F2. More over, RBF2 and dE2F2 act synergistically to antagonize dE2F1-mediated activation, and they co-operate to block S phase progression in transgenic animals. The network of interactions between RBF1 or RBF2 and dE2F1 or dE2F2 reveals how the activities of these proteins are integrated. These results suggest that there is a remarkable degree of symmetry in the arrangement of E2F and RB family members in mammalian cells and in DROSOPHILA.
Collapse
Affiliation(s)
| | | | | | | | | | - Nicholas Dyson
- Massachusetts General Hospital Cancer Center, Laboratory of Molecular Oncology, Charlestown, MA 02129, USA
Corresponding author e-mail:
| |
Collapse
|
33
|
Hirose F, Ohshima N, Kwon EJ, Yoshida H, Yamaguchi M. Drosophila Mi-2 negatively regulates dDREF by inhibiting its DNA-binding activity. Mol Cell Biol 2002; 22:5182-93. [PMID: 12077345 PMCID: PMC139784 DOI: 10.1128/mcb.22.14.5182-5193.2002] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Drosophila melanogaster DNA replication-related element (DRE) factor (dDREF) is a transcriptional regulatory factor required for the expression of genes carrying the 5'-TATCGATA DRE. dDREF has been reported to bind to a sequence in the chromatin boundary element, and thus, dDREF may play a part in regulating insulator activity. To generate further insights into dDREF function, we carried out a Saccharomyces cerevisiae two-hybrid screening with DREF polypeptide as bait and identified Mi-2 as a DREF-interacting protein. Biochemical analyses revealed that the C-terminal region of Drosophila Mi-2 (dMi-2) specifically binds to the DNA-binding domain of dDREF. Electrophoretic mobility shift assays showed that dMi-2 thereby inhibits the DNA-binding activity of dDREF. Ectopic expression of dDREF and dMi-2 in eye imaginal discs resulted in severe and mild rough-eye phenotypes, respectively, whereas flies simultaneously expressing both proteins exhibited almost-normal eye phenotypes. Half-dose reduction of the dMi-2 gene enhanced the DREF-induced rough-eye phenotype. Immunostaining of polytene chromosomes of salivary glands showed that dDREF and dMi-2 bind in mutually exclusive ways. These lines of evidence define a novel function of dMi-2 in the negative regulation of dDREF by its DNA-binding activity. Finally, we postulated that dDREF and dMi-2 may demonstrate reciprocal regulation of their functions.
Collapse
Affiliation(s)
- Fumiko Hirose
- Division of Biochemistry, Aichi Cancer Center Research Institute, Chikusa-ku, Nagoya 464-8681, Japan.
| | | | | | | | | |
Collapse
|
34
|
Noya F, Chien WM, Wu X, Banerjee NS, Kappes JC, Broker TR, Chow LT. The promoter of the human proliferating cell nuclear antigen gene is not sufficient for cell cycle-dependent regulation in organotypic cultures of keratinocytes. J Biol Chem 2002; 277:17271-80. [PMID: 11877408 DOI: 10.1074/jbc.m112441200] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The proliferating cell nuclear antigen (PCNA) is essential for DNA replication of mammalian cells and their small DNA tumor viruses. The mechanism of the cell cycle-dependent regulation of the human PCNA promoter is not clear despite extensive investigations. In this report, we employed organotypic cultures of primary human keratinocytes, which closely resemble native skin comprising both proliferating and postmitotic, differentiated cells, to examine the cell cycle-dependent regulation of the human PCNA gene (hPCNA) in the absence or presence of the human papillomavirus type 18 (HPV-18) E7 protein. HPV-18 E7 promotes S phase re-entry in post-mitotic differentiated keratinocytes by abrogating the transcription repression of E2F transcription factors by the retinoblastoma susceptibility protein, pRb. We demonstrated that E7 reactivated the transcription of the endogenous hPCNA in differentiated keratinocytes. In contrast, with or without E7, the expression of a transduced hPCNA promoter-driven reporter did not correlate with that of the endogenous hPCNA gene in either proliferating or differentiated cells. Moreover, in Chinese hamster ovary and L-cells, HPV E7 and the adenovirus E1A protein repressed the transduced hPCNA promoter, but both activated an extended promoter construct spanning the first intron. Mutations of two E2F sites in the intron reduced the basal activity and abolished the response to E7 or E1A. Promoter repression or activation required the CR2 domain of E7 and, to a lesser extent, CR1 as well. However, in organotypic cultures, this extended promoter construct failed to recapitulate the cell cycle-dependent regulation of the endogenous hPCNA gene. Only when a full-length Myc-tagged hPCNA spanning the 5' promoter and all exons and introns was used was the native pattern of expression largely restored, indicative of the complexity of its regulation.
Collapse
Affiliation(s)
- Francisco Noya
- Department of Biochemistry, University of Alabama at Birmingham, 35294-0005, USA
| | | | | | | | | | | | | |
Collapse
|
35
|
Hirose F, Ohshima N, Shiraki M, Inoue YH, Taguchi O, Nishi Y, Matsukage A, Yamaguchi M. Ectopic expression of DREF induces DNA synthesis, apoptosis, and unusual morphogenesis in the Drosophila eye imaginal disc: possible interaction with Polycomb and trithorax group proteins. Mol Cell Biol 2001; 21:7231-42. [PMID: 11585906 PMCID: PMC99898 DOI: 10.1128/mcb.21.21.7231-7242.2001] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The promoters of Drosophila genes encoding DNA replication-related proteins contain transcription regulatory element DRE (5'-TATCGATA) in addition to E2F recognition sites. A specific DRE-binding factor, DREF, positively regulates DRE-containing genes. In addition, it has been reported that DREF can bind to a sequence in the hsp70 scs' chromatin boundary element that is also recognized by boundary element-associated factor, and thus DREF may participate in regulating insulator activity. To examine DREF function in vivo, we established transgenic flies in which ectopic expression of DREF was targeted to the eye imaginal discs. Adult flies expressing DREF exhibited a severe rough eye phenotype. Expression of DREF induced ectopic DNA synthesis in the cells behind the morphogenetic furrow, which are normally postmitotic, and abolished photoreceptor specifications of R1, R6, and R7. Furthermore, DREF expression caused apoptosis in the imaginal disc cells in the region where commitment to R1/R6 cells takes place, suggesting that failure of differentiation of R1/R6 photoreceptor cells might cause apoptosis. The DREF-induced rough eye phenotype was suppressed by a half-dose reduction of the E2F gene, one of the genes regulated by DREF, indicating that the DREF overexpression phenotype is useful to screen for modifiers of DREF activity. Among Polycomb/trithorax group genes, we found that a half-dose reduction of some of the trithorax group genes involved in determining chromatin structure or chromatin remodeling (brahma, moira, and osa) significantly suppressed and that reduction of Distal-less enhanced the DREF-induced rough eye phenotype. The results suggest a possibility that DREF activity might be regulated by protein complexes that play a role in modulating chromatin structure. Genetic crosses of transgenic flies expressing DREF to a collection of Drosophila deficiency stocks allowed us to identify several genomic regions, deletions of which caused enhancement or suppression of the DREF-induced rough eye phenotype. These deletions should be useful to identify novel targets of DREF and its positive or negative regulators.
Collapse
Affiliation(s)
- F Hirose
- Division of Biochemistry, Aichi Cancer Center Research Institute, Chikusa-ku, Nagoya 464-8681, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
36
|
Frolov MV, Huen DS, Stevaux O, Dimova D, Balczarek-Strang K, Elsdon M, Dyson NJ. Functional antagonism between E2F family members. Genes Dev 2001; 15:2146-60. [PMID: 11511545 PMCID: PMC312757 DOI: 10.1101/gad.903901] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
E2F is a heterogenous transcription factor and its role in cell cycle control results from the integrated activities of many different E2F family members. Unlike mammalian cells, that have a large number of E2F-related genes, the Drosophila genome encodes just two E2F genes, de2f1 and de2f2. Here we show that de2f1 and de2f2 provide different elements of E2F regulation and that they have opposing functions during Drosophila development. dE2F1 and dE2F2 both heterodimerize with dDP and bind to the promoters of E2F-regulated genes in vivo. dE2F1 is a potent activator of transcription, and the loss of de2f1 results in the reduced expression of E2F-regulated genes. In contrast, dE2F2 represses the transcription of E2F reporters and the loss of de2f2 function results in increased and expanded patterns of gene expression. The loss of de2f1 function has previously been reported to compromise cell proliferation. de2f1 mutant embryos have reduced expression of E2F-regulated genes, low levels of DNA synthesis, and hatch to give slow-growing larvae. We find that these defects are due in large part to the unchecked activity of dE2F2, since they can be suppressed by mutation of de2f2. Examination of eye discs from de2f1; de2f2 double-mutant animals reveals that relatively normal patterns of DNA synthesis can occur in the absence of both E2F proteins. This study shows how repressor and activator E2Fs are used to pattern transcription and how the net effect of E2F on cell proliferation results from the interplay between two types of E2F complexes that have antagonistic functions.
Collapse
Affiliation(s)
- M V Frolov
- Massachusetts General Hospital Cancer Center, Charlestown, Massachusetts 02129, USA
| | | | | | | | | | | | | |
Collapse
|
37
|
Kwon EJ, Oh EJ, Kim YS, Hirose F, Ohno K, Nishida Y, Matsukage A, Yamaguchi M, Yoo MA. E2F-dependent transcription of the raf proto-oncogene during Drosophila development. Nucleic Acids Res 2001; 29:1808-14. [PMID: 11292854 PMCID: PMC31312 DOI: 10.1093/nar/29.8.1808] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
D-raf, a Drosophila homolog of the raf proto-oncogene, has diverse functions throughout development and is transcribed in a wide range of tissues, with high levels of expression in the ovary and in association with rapid proliferation. The expression pattern resembles those of S phase genes, which are regulated by E2F transcription factors. In the 5'-flanking region of D-raf, four sequences (E2F sites 1-4) similar to the E2F recognition sequence were found, one of them (E2F site 3) being recognized efficiently by Drosophila E2F (dE2F) in vitro. Transient luciferase expression assays confirmed activation of the D-raf gene promoter by dE2F/dDP. Expression of Draf-lacZ was greatly reduced in embryos homozygous for the dE2F mutation. These results suggest that dE2F is likely to be an important regulator of D-raf transcription.
Collapse
Affiliation(s)
- E J Kwon
- Department of Molecular Biology, College of Natural Science, Pusan National University, Pusan 609-735, Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
38
|
Myster DL, Bonnette PC, Duronio RJ. A role for the DP subunit of the E2F transcription factor in axis determination during Drosophila oogenesis. Development 2000; 127:3249-61. [PMID: 10887081 DOI: 10.1242/dev.127.15.3249] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The E2F family of transcription factors contributes to cell cycle control by regulating the transcription of DNA replication factors. Functional ‘E2F’ is a DNA-binding heterodimer composed of E2F and DP proteins. Drosophila contains two E2F genes (dE2F, dE2F2) and one DP gene (dDP). Mutation of either dE2F or dDP eliminates G(1)-S transcription of known replication factors during embryogenesis and compromises DNA replication. However, the analysis of these mutant phenotypes is complicated by the perdurance of maternally supplied gene function. To address this and to further analyze the role of E2F transcription factors in development we have phenotypically characterized mitotic clones of dDP mutant cells in the female germline. Our analysis indicates that dDP is required for several essential processes during oogenesis. In a fraction of the mutant egg chambers the germ cells execute one extra round of mitosis, suggesting that in this tissue dDP is uniquely utilized for cell cycle arrest rather than cell cycle progression. Mutation of dDP in the germline also prevents nurse cell cytoplasm transfer to the oocyte, resulting in a ‘dumpless’ phenotype that blocks oocyte development. This phenotype likely results from both disruption of the actin cytoskeleton and a failure of nurse cell apoptosis, each of which are required for normal cytoplasmic transfer. Lastly, we found that dDP is required for the establishment of the dorsal-ventral axis, as loss of dDP function prevents the localized expression of the EGFR ligand Gurken in the oocyte, which initiates dorsal-ventral polarity in the egg chamber. Thus we have uncovered new functions for E2F transcription factors during development, including an unexpected role in pattern formation.
Collapse
Affiliation(s)
- D L Myster
- Department of Biology, Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | | | | |
Collapse
|
39
|
Ruiz De Mena I, Lefai E, Garesse R, Kaguni LS. Regulation of mitochondrial single-stranded DNA-binding protein gene expression links nuclear and mitochondrial DNA replication in drosophila. J Biol Chem 2000; 275:13628-36. [PMID: 10788480 DOI: 10.1074/jbc.275.18.13628] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The structural organization of the Drosophila melanogaster gene encoding mitochondrial single-stranded DNA-binding protein (mtSSB) has been determined and its pattern of expression evaluated during Drosophila development. The D. melanogaster mtSSB gene contains four exons and three small introns. The transcriptional initiation site is located 22 nucleotides upstream from the initiator translation codon in adults, whereas several initiation sites are found in embryos. No consensus TATA or CAAT sequences are located at canonical positions, although an AT-rich sequence was identified flanking the major transcriptional initiation site. Northern analyses indicated that the mtSSB transcript is present at variable levels throughout development. In situ hybridization analysis shows that maternally deposited mtSSB mRNA is distributed homogeneously in the early embryo, whereas de novo transcript is produced specifically at an elevated level in the developing midgut. Transfection assays in cultured Schneider cells with promoter region deletion constructs revealed that the proximal 230 nucleotides contain cis-acting elements required for efficient gene expression. Putative transcription factor binding sites clustered within this region include two Drosophila DNA replication-related elements (DRE) and a single putative E2F binding site. Deletion and base substitution mutagenesis of the DRE sites demonstrated that they are required for efficient promoter activity, and gel electrophoretic mobility shift analyses showed that DRE binding factor (DREF) binds to these sites. Our data suggest strongly that the Drosophila mtSSB gene is regulated by the DRE/DREF system. This finding represents a first link between nuclear and mitochondrial DNA replication.
Collapse
Affiliation(s)
- I Ruiz De Mena
- Department of Biochemistry, Michigan State University, East Lansing, Michigan 48824-1319, USA
| | | | | | | |
Collapse
|
40
|
Hayashi Y, Yamagishi M, Nishimoto Y, Taguchi O, Matsukage A, Yamaguchi M. A binding site for the transcription factor Grainyhead/Nuclear transcription factor-1 contributes to regulation of the Drosophila proliferating cell nuclear antigen gene promoter. J Biol Chem 1999; 274:35080-8. [PMID: 10574988 DOI: 10.1074/jbc.274.49.35080] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Drosophila proliferating cell nuclear antigen promoter contains multiple transcriptional regulatory elements, including upstream regulatory element (URE), DNA replication-related element, E2F recognition sites, and three common regulatory factor for DNA replication and DNA replication-related element-binding factor genes recognition sites. In nuclear extracts of Drosophila embryos, we detected a protein factor, the URE-binding factor (UREF), that recognizes the nucleotide sequence 5'-AAACCAGTTGGCA located within URE. Analyses in Drosophila Kc cells and transgenic flies revealed that the UREF-binding site plays an important role in promoter activity both in cultured cells and in living flies. A yeast one-hybrid screen using URE as a bait allowed isolation of a cDNA encoding a transcription factor, Grainyhead/nuclear transcription factor-1 (GRH/NTF-1). The nucleotide sequence required for binding to GRH was indistinguishable from that for UREF detected in embryo nuclear extracts. Furthermore, a specific antibody to GRH reacted with UREF in embryo nuclear extracts. From these results we conclude that GRH is identical to UREF. Although GRH has been thought to be involved in regulation of differentiation-related genes, this study demonstrates, for the first time, involvement of a GRH-binding site in regulation of the DNA replication-related proliferating cell nuclear antigen gene.
Collapse
Affiliation(s)
- Y Hayashi
- Laboratory of Cell Biology, Aichi Cancer Center Research Institute, Chikusa-ku, Nagoya, 464-8681, Japan
| | | | | | | | | | | |
Collapse
|
41
|
Hirose F, Yamaguchi M, Matsukage A. Targeted expression of the DNA binding domain of DRE-binding factor, a Drosophila transcription factor, attenuates DNA replication of the salivary gland and eye imaginal disc. Mol Cell Biol 1999; 19:6020-8. [PMID: 10454549 PMCID: PMC84493 DOI: 10.1128/mcb.19.9.6020] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The promoters of Drosophila genes encoding DNA replication-related proteins contain transcription regulatory elements consisting of an 8-bp palindromic DNA replication-related element (DRE) sequence (5'-TATCGATA). The specific DRE-binding factor (DREF), a homodimer of the polypeptide with 709 amino acid residues, is a positive trans-acting factor for transcription of DRE-containing genes. Both DRE binding and dimer formation are associated with residues 16 to 115 of the N-terminal region. We have established transgenic flies expressing the full-length DREF polypeptide or its N-terminal fragment (amino acid residues 1 to 125) under the control of the heat shock promoter, the salivary gland-specific promoter, or the eye imaginal disc-specific promoter. Heat shock induction of the N-terminal fragment during embryonic, larval, or pupal stages caused greater than 50% lethality. This lethality was overcome by coexpression of the full-length DREF. In salivary glands of the transgenic larvae expressing the N-terminal fragment, this fragment formed a homodimer and a heterodimer with the endogenous DREF. Ectopic expression of the N-terminal fragment in salivary gland cells reduced the contents of mRNAs for the 180-kDa subunit of DNA polymerase alpha and for dE2F and the extent of DNA endoreplication. Ectopic expression of the N-terminal fragment in the eye imaginal discs significantly reduced DNA replication in cells at the second mitotic wave. The lines of evidence suggest that the N-terminal fragment can impede the endogenous DREF function in a dominant negative manner and that DREF is required for normal DNA replication in both mitotic cell cycle and endo cycle.
Collapse
Affiliation(s)
- F Hirose
- Laboratory of Cell Biology, Aichi Cancer Center Research Institute, Chikusa-ku, Nagoya, 464-8681, Japan
| | | | | |
Collapse
|
42
|
Timchenko NA, Wilde M, Iakova P, Albrecht JH, Darlington GJ. E2F/p107 and E2F/p130 complexes are regulated by C/EBPalpha in 3T3-L1 adipocytes. Nucleic Acids Res 1999; 27:3621-30. [PMID: 10446255 PMCID: PMC148609 DOI: 10.1093/nar/27.17.3621] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We have previously found that loss of C/EBPalpha in hepatocytes of newborn livers leads to increased proliferation, to a reduction in p21 protein levels and to an induction of S phase-specific E2F/p107 complexes. In this paper, we investigated C/EBPalpha-dependent regulation of E2F complexes in a well-characterized cell line, 3T3-L1, and in stable transformants that conditionally express C/EBPalpha. C/EBPalpha and C/EBPbeta proteins are induced in 3T3-L1 preadipocytes during differentiation with different kinetics and potentially may regulate E2F/Rb family complexes. In pre-differentiated cells, three E2F complexes are observed: cdk2/E2F/p107, E2F/p130 and E2F4. cdk2/E2F/p107 complexes are induced in nuclear extracts of 3T3-L1 cells during mitotic expansion, but are not detectable in nuclear extracts at later stages of 3T3-L1 differentiation. The reduction in E2F/p107 complexes is associated with elevation of C/EBPalpha, but is independent of C/EBPbeta expression. Bacterially expressed, purified His-C/EBPalpha is able to disrupt E2F/p107 complexes that are observed at earlier stages of 3T3-L1 differentiation. C/EBPbeta, however, does not disrupt E2F/p107 complexes. A short C/EBPalpha peptide with homology to E2F is sufficient to bring about the disruption of E2F/p107 complexes from 3T3-L1 cells in vitro. Induction of C/EBPalpha in stable 3T3-L1 clones revealed that C/EBPalpha causes disruption of p107/E2F complexes in these cells. In contrast, E2F/p130 complexes are induced in cells expressing C/EBPalpha. Our data suggest that induction of p130/E2F complexes by C/EBPalpha occurs via up-regulation of p21, which, in turn, leads to association with and inhibition of, cdk2 kinase activity. The reduction in cdk2 kinase activity correlates with alterations of p130 phosphorylation and with induction of p130/E2F complexes in 3T3-L1 stable clones. Our data suggest two pathways of C/EBPalpha-dependent regulation of E2F/Rb family complexes: disruption of S phase-specific E2F/p107 complexes and induction of E2F/p130 complexes.
Collapse
Affiliation(s)
- N A Timchenko
- Huffington Center on Aging, Department of Pathology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
| | | | | | | | | |
Collapse
|
43
|
Abstract
Preservation of the structural integrity of DNA in any organism is crucial to its health and survival. Such preservation is achieved by an extraordinary cellular arsenal of damage surveillance and repair functions, many of which are now being defined at the gene and protein levels. Mutants hypersensitive to the killing effects of DNA-damaging agents have been instrumental in helping to identify DNA repair-related genes and to elucidate repair mechanisms. In Drosophila melanogaster, such strains are generally referred to as mutagen-sensitive (mus) mutants and currently define more than 30 genetic loci. Whereas most mus mutants have been recovered on the basis of hypersensitivity to the monofunctional alkylating agent methyl methanesulfonate, they nevertheless constitute a phenotypically diverse group, with many mutants having effects beyond mutagen sensitivity. These phenotypes include meiotic dysfunctions, somatic chromosome instabilities, chromatin abnormalities, and cell proliferation defects. Within the last few years numerous mus and other DNA repair-related genes of Drosophila have been molecularly cloned, providing new insights into the functions of these genes. This article outlines strategies for isolating mus mutations and reviews recent advances in the Drosophila DNA repair field, emphasizing mutant analysis and gene cloning.
Collapse
Affiliation(s)
- D S Henderson
- Department of Anatomy and Physiology, University of Dundee, Dundee, DD1 4HN, Scotland, United Kingdom
| |
Collapse
|
44
|
Timchenko NA, Wilde M, Darlington GJ. C/EBPalpha regulates formation of S-phase-specific E2F-p107 complexes in livers of newborn mice. Mol Cell Biol 1999; 19:2936-45. [PMID: 10082561 PMCID: PMC84088 DOI: 10.1128/mcb.19.4.2936] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We previously showed that the rate of hepatocyte proliferation in livers from newborn C/EBPalpha knockout mice was increased. An examination of cell cycle-related proteins showed that the cyclin-dependent kinase (CDK) inhibitor p21 level was reduced in the knockout animals compared to that in wild-type littermates. Here we show additional cell cycle-associated proteins that are affected by C/EBPalpha. We have observed that C/EBPalpha controls the composition of E2F complexes through interaction with the retinoblastoma (Rb)-like protein, p107, during prenatal liver development. S-phase-specific E2F complexes containing E2F, DP, cdk2, cyclin A, and p107 are observed in the developing liver. In wild-type animals these complexes disappear by day 18 of gestation and are no longer present in the newborn animals. In the C/EBPalpha mutant, the S-phase-specific complexes do not diminish and persist to birth. The elevation of levels of the S-phase-specific E2F-p107 complexes in C/EBPalpha knockout mice correlates with the increased expression of several E2F-dependent genes such as those that encode cyclin A, proliferating cell nuclear antigen, and p107. The C/EBPalpha-mediated regulation of E2F binding is specific, since the deletion of another C/EBP family member, C/EBPbeta, does not change the pattern of E2F binding during prenatal liver development. The addition of bacterially expressed, purified His-C/EBPalpha to the E2F binding reaction resulted in the disruption of E2F complexes containing p107 in nuclear extracts from C/EBPalpha knockout mouse livers. Ectopic expression of C/EBPalpha in cultured cells also leads to a reduction of E2F complexes containing Rb family proteins. Coimmunoprecipitation analyses revealed an interaction of C/EBPalpha with p107 but none with cdk2, E2F1, or cyclin A. A region of C/EBPalpha that has sequence similarity to E2F is sufficient for the disruption of the E2F-p107 complexes. Despite its role as a DNA binding protein, C/EBPalpha brings about a change in E2F complex composition through a protein-protein interaction. The disruption of E2F-p107 complexes correlates with C/EBPalpha-mediated growth arrest of hepatocytes in newborn animals.
Collapse
Affiliation(s)
- N A Timchenko
- Department of Pathology, Baylor College of Medicine, Houston, Texas 77030, USA.
| | | | | |
Collapse
|
45
|
Abstract
A modified cell cycle, the endo cycle, produces the polyploid or polytene cells that are present in some tissues of most organisms. In the endo cycle, the S phase alternates with a gap phase, but mitosis does not occur. Genes needed to inhibit mitosis during the endo cycle and to promote the onset of S phase have been identified in Drosophila. Genomic intervals are differentially replicated during the endo cycle S phase such that some regions are under-replicated, while others can be amplified. Cyclin E and E2F are needed for this differential DNA replication during Drosophila oogenesis.
Collapse
Affiliation(s)
- I Royzman
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | | |
Collapse
|
46
|
Sawado T, Yamaguchi M, Nishimoto Y, Ohno K, Sakaguchi K, Matsukage A. dE2F2, a novel E2F-family transcription factor in Drosophila melanogaster. Biochem Biophys Res Commun 1998; 251:409-15. [PMID: 9792788 DOI: 10.1006/bbrc.1998.9407] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mammalian E2F transcription factors comprise a family of proteins encoded by distinct genes which function in the form of heterodimers with DP proteins. In Drosophila melanogaster, only a single E2F-related transcription factor, dE2F, has been reported. We have now identified and characterized a cDNA encoding another E2F family member in Drosophila, termed dE2F2. The predicted amino acid sequence shares 38.8% identity with dE2F, including the QKRRIYDITNVLEGI motif which is highly conserved in mammalian E2F family members and dE2F. The 18 amino acids, located in the carboxy-terminal region of the mammalian E2F family, sufficient for binding to pRb are also conserved in dE2F2. Band mobility shift analyses with glutathione S-transferase fusion proteins revealed dE2F2 binding to E2F-recognition sites to be dependent on the presence of dDP protein, in apparent contrast to dE2F. Furthermore, cotransfection experiments in Kc cells demonstrated dE2F2 repression of the PCNA gene promoter activity, while dE2F caused activation, the target site for the repression being identical to the dE2F-recognition site.
Collapse
Affiliation(s)
- T Sawado
- Laboratory of Cell Biology, Aichi Cancer Center Research Institute, Science University of Tokyo, Japan
| | | | | | | | | | | |
Collapse
|
47
|
Sawado T, Hirose F, Takahashi Y, Sasaki T, Shinomiya T, Sakaguchi K, Matsukage A, Yamaguchi M. The DNA replication-related element (DRE)/DRE-binding factor system is a transcriptional regulator of the Drosophila E2F gene. J Biol Chem 1998; 273:26042-51. [PMID: 9748283 DOI: 10.1074/jbc.273.40.26042] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Two mRNA species were observed for the Drosophila E2F (dE2F) gene, differing with regard to the first exons (exon 1-a and exon 1-b), which were expressed differently during development. A single transcription initiation site for mRNA containing exon 1-b was mapped by primer extension analysis and numbered +1. We found three tandemly aligned sequences, similar to the DNA replication-related element (DRE; 5'-TATCGATA), which is commonly required for transcription of genes related to DNA replication and cell proliferation, in the region upstream of this site. Band mobility shift analyses using oligonucleotides containing the DRE-related sequences with or without various base substitutions revealed that two out of three DRE-related sequences are especially important for binding to the DRE-binding factor (DREF). On footprinting analysis with Kc cell nuclear extracts and a glutathione S-transferase fusion protein with the N-terminal fragment (1-125 amino acid residues) of DREF, all three DRE-related sequences were found to be protected. Transient luciferase expression assays in Kc cells demonstrated that the region containing the three DRE-related sequences is required for high promoter activity. We have established transgenic lines of Drosophila in which ectopic expression of DREF was targeted to the eye imaginal disc cells. Overexpression of DREF in eye imaginal disc cells enhanced the promoter activity of dE2F. The obtained results indicate that the DRE/DREF system activates transcription of the dE2F gene.
Collapse
Affiliation(s)
- T Sawado
- Laboratory of Cell Biology, Aichi Cancer Center Research Institute, Aichi 464-8681, Japan
| | | | | | | | | | | | | | | |
Collapse
|
48
|
Akimoto M, Hangai M, Okazaki K, Kogishi J, Honda Y, Kaneda Y. Growth inhibition of cultured human Tenon's fibroblastic cells by targeting the E2F transcription factor. Exp Eye Res 1998; 67:395-401. [PMID: 9820786 DOI: 10.1006/exer.1998.0531] [Citation(s) in RCA: 16] [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 transcription factor E2F regulates the expression of several genes concerned with cell growth. The ability to inhibit transcription by blocking E2F expression has great potential in the treatment of proliferative disorders. The effect of double-stranded phosphorothioate oligonucleotides containing E2F transcription factor cis element, a so called 'decoy' has examined on the growth of cultured human Tenon's fibroblastic cells. Human Tenon's fibroblastic cells were cultured and challenged by E2F decoy coated with the Hemagglutinating virus of Japan (HVJ) cationic liposomes (HVJ-CL). The outcome was evaluated using fluorescence microscopy, RT-PCR and growth assays. HVJ-CL facilitated the transfer of external oligonucleotides to cultured human Tenon's fibroblastic cells. The E2F decoy, transferred by HVJ-CL, inhibited simultaneously the expression of the mRNAs of several cell cycle related genes such as c-myc, cdc2, proliferative cell nuclear antigen, and dehydrofolate reductase. Entry into S phase was also reduced to 42.7% of the positive control by the E2F decoy. The total increase of DNA at four days was reduced to 59.7% of the positive control by 5 microM and 29.9% by 15 microM of E2F decoy. It is concluded that gene therapy using the E2F transcription factor offers a potential therapeutic modality for the treatment of proliferative disorders such as proliferative vitreoretinopathy and fibrosis following filtering surgery.
Collapse
Affiliation(s)
- M Akimoto
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | | | | | | | | | | |
Collapse
|
49
|
Ohno K, Hirose F, Inoue YH, Takisawa H, Mimura S, Hashimoto Y, Kiyono T, Nishida Y, Matsukage A. cDNA cloning and expression during development of Drosophila melanogaster MCM3, MCM6 and MCM7. Gene X 1998; 217:177-85. [PMID: 9795205 DOI: 10.1016/s0378-1119(98)00358-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Abstract
cDNAs encoding three Drosophila melanogaster MCM proteins, DmMCM3, DmMCM6 and DmMCM7, candidates of DNA replication-licensing factors, were cloned and sequenced. The deduced amino-acid sequences displayed 60, 59 and 68% identities with the respective Xenopus laevis homologues, XMCM3, XMCM6 and XMCM7. Six members of the D. melanogaster MCM family were found to share 31-36% identities in their amino-acid sequences, and to possess the five common domains carrying conserved amino-acid sequences as reported with X. laevis MCM proteins. DmMCM3, DmMCM6 and DmMCM7 genes were mapped to the 4F region on the X chromosome, the 6B region on the X chromosome and the 66E region on the third chromosome, respectively, by in situ hybridization. Contents of their mRNAs were proved to be high in unfertilized eggs and early embryos (0-4h after fertilization), then decrease gradually by the 12h time point, with only low levels detected at later stages of development except in adult females. This fluctuation pattern is similar to those of genes for proteins involved in DNA replication, such as DNA polymerase alpha and proliferating cell nuclear antigen, suggesting that expression of DmMCM genes is under the regulatory mechanism which regulates expression of other genes involved in DNA replication.
Collapse
Affiliation(s)
- K Ohno
- Laboratory of Cell Biology, Aichi Cancer Center Research Institute, Chikusa-ku, Nagoya 464-8681, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Suzuki S, Adachi A, Hiraiwa A, Ohashi M, Ishibashi M, Kiyono T. Cloning and characterization of human MCM7 promoter. Gene 1998; 216:85-91. [PMID: 9714754 DOI: 10.1016/s0378-1119(98)00323-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
MCM7 is a member of the MCM protein family which has been implicated in the regulatory machinery allowing DNA to replicate only once during S phase. In quiescent cells, human MCM7 (hMCM7) mRNA is almost undetectable. Stimulation of cells to enter the cell cycle results in induction of hMCM7 expression. Here, we report cloning and characterization of the hMCM7 promoter. We isolated and sequenced a 0.5 kb genomic fragment that contains putative transcription factor binding sites including three E2F sites, three GC boxes and an E box. Several transcription start sites, which were used upon growth stimulation, were identified. The minimal promoter region required for transcription of a luciferase reporter gene was delineated, and it contained an E box and one E2F site, which were important for promoter activity. Interestingly, the cloned sequence appears to act as a promoter for mu-adaptin-related protein 2 (mu-ARP2) gene in the opposite orientation.
Collapse
Affiliation(s)
- S Suzuki
- Department of Dermatology, Nagoya University, School of Medicine, 65 Tsurumai, Syouwa-ku, Nagoya 466, Japan
| | | | | | | | | | | |
Collapse
|