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The Immune Regulatory Role of Protein Kinase CK2 and Its Implications for Treatment of Cancer. Biomedicines 2021; 9:biomedicines9121932. [PMID: 34944749 PMCID: PMC8698504 DOI: 10.3390/biomedicines9121932] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 01/15/2023] Open
Abstract
Protein Kinase CK2, a constitutively active serine/threonine kinase, fulfills its functions via phosphorylating hundreds of proteins in nearly all cells. It regulates a variety of cellular signaling pathways and contributes to cell survival, proliferation and inflammation. CK2 has been implicated in the pathogenesis of hematologic and solid cancers. Recent data have documented that CK2 has unique functions in both innate and adaptive immune cells. In this article, we review aspects of CK2 biology, functions of the major innate and adaptive immune cells, and how CK2 regulates the function of immune cells. Finally, we provide perspectives on how CK2 effects in immune cells, particularly T-cells, may impact the treatment of cancers via targeting CK2.
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2
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Deoxynucleosides with benzimidazoles as aglycone moiety are potent anticancer agents. Eur J Pharmacol 2018; 820:146-155. [DOI: 10.1016/j.ejphar.2017.12.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 12/01/2017] [Accepted: 12/08/2017] [Indexed: 12/12/2022]
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3
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Buontempo F, McCubrey JA, Orsini E, Ruzzene M, Cappellini A, Lonetti A, Evangelisti C, Chiarini F, Evangelisti C, Barata JT, Martelli AM. Therapeutic targeting of CK2 in acute and chronic leukemias. Leukemia 2017; 32:1-10. [PMID: 28951560 PMCID: PMC5770594 DOI: 10.1038/leu.2017.301] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 09/06/2017] [Accepted: 09/08/2017] [Indexed: 12/22/2022]
Abstract
CK2 is a ubiquitously expressed, constitutively active Ser/Thr protein kinase, which is considered the most pleiotropic protein kinase in the human kinome. Such a pleiotropy explains the involvement of CK2 in many cellular events. However, its predominant roles are stimulation of cell growth and prevention of apoptosis. High levels of CK2 messenger RNA and protein are associated with CK2 pathological functions in human cancers. Over the last decade, basic and translational studies have provided evidence of CK2 as a pivotal molecule driving the growth of different blood malignancies. CK2 overexpression has been demonstrated in nearly all the types of hematological cancers, including acute and chronic leukemias, where CK2 is a key regulator of signaling networks critical for cell proliferation, survival and drug resistance. The findings that emerged from these studies suggest that CK2 could be a valuable therapeutic target in leukemias and supported the initiation of clinical trials using CK2 antagonists. In this review, we summarize the recent advances on the understanding of the signaling pathways involved in CK2 inhibition-mediated effects with a particular emphasis on the combinatorial use of CK2 inhibitors as novel therapeutic strategies for treating both acute and chronic leukemia patients.
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Affiliation(s)
- F Buontempo
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - J A McCubrey
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - E Orsini
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - M Ruzzene
- Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - A Cappellini
- Department of Human, Social and Health Sciences, University of Cassino, Cassino, Italy
| | - A Lonetti
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - C Evangelisti
- Institute of Molecular Genetics, National Research Council, Bologna, Italy.,Cell and Molecular Biology Laboratory, Rizzoli Orthopedic Institute, Bologna, Italy
| | - F Chiarini
- Institute of Molecular Genetics, National Research Council, Bologna, Italy.,Cell and Molecular Biology Laboratory, Rizzoli Orthopedic Institute, Bologna, Italy
| | - C Evangelisti
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - J T Barata
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - A M Martelli
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
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Protein Kinase CK2: A Targetable BCR-ABL Partner in Philadelphia Positive Leukemias. Adv Hematol 2015; 2015:612567. [PMID: 26843864 PMCID: PMC4710905 DOI: 10.1155/2015/612567] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 12/20/2015] [Indexed: 12/23/2022] Open
Abstract
BCR-ABL-mediated leukemias, either Chronic Myeloid Leukemia (CML) or Philadelphia positive Acute Lymphoblastic Leukemia (ALL), are the paradigm of targeted molecular therapy of cancer due to the impressive clinical responses obtained with BCR-ABL specific tyrosine kinase inhibitors (TKIs). However, BCR-ABL TKIs do not allow completely eradicating both CML and ALL. Furthermore, ALL therapy is associated with much worse responses to TKIs than those observed in CML. The identification of additional pathways that mediate BCR-ABL leukemogenesis is indeed mandatory to achieve synthetic lethality together with TKI. Here, we review the role of BCR-ABL/protein kinase CK2 interaction in BCR-ABL leukemias, with potentially relevant implications for therapy.
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Aberrant signalling by protein kinase CK2 in imatinib-resistant chronic myeloid leukaemia cells: biochemical evidence and therapeutic perspectives. Mol Oncol 2013; 7:1103-15. [PMID: 24012109 DOI: 10.1016/j.molonc.2013.08.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 08/11/2013] [Accepted: 08/12/2013] [Indexed: 11/20/2022] Open
Abstract
Chronic myeloid leukaemia (CML) is driven by the fusion protein Bcr-Abl, a constitutively active tyrosine kinase playing a crucial role in initiation and maintenance of CML phenotype. Despite the great efficacy of the Bcr-Abl-specific inhibitor imatinib, resistance to this drug is recognized as a major problem in CML treatment. We found that in LAMA84 cells, characterized by imatinib-resistance caused by BCR-ABL1 gene amplification, the pro-survival protein kinase CK2 is up-regulated as compared to the sensitive cells. CK2 exhibits a higher protein-level and a parallel enhancement of catalytic activity. Consistently, CK2-catalysed phosphorylation of Akt-Ser129 is increased. CK2 co-localizes with Bcr-Abl in the cytoplasmic fraction as judged by subcellular fractionation and fluorescence immunolocalization. CK2 and Bcr-Abl are members of the same multi-protein complex(es) in imatinib-resistant cells as demonstrated by co-immunoprecipitation and co-sedimentation in glycerol gradients. Cell treatment with CX-4945, a CK2 inhibitor currently in clinical trials, counteracts CK2/Bcr-Abl interaction and causes cell death by apoptosis. Interestingly, combination of CX-4945 with imatinib displays a synergistic effect in reducing cell viability. Consistently, knockdown of CK2α expression by siRNA restores the sensitivity of resistant LAMA84 cells to low imatinib concentrations. Remarkably, the CK2/Bcr-Abl interaction and the sensitization towards imatinib obtained by CK2-inhibition in LAMA84 is observable also in other imatinib-resistant CML cell lines. These results demonstrate that CK2 contributes to strengthen the imatinib-resistance phenotype of CML cells conferring survival advantage against imatinib. We suggest that CK2 inhibition might be a promising tool for combined strategies in CML therapy.
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Noy P, Gaston K, Jayaraman PS. Dasatinib inhibits leukaemic cell survival by decreasing PRH/Hhex phosphorylation resulting in increased repression of VEGF signalling genes. Leuk Res 2012; 36:1434-7. [PMID: 22874537 PMCID: PMC3462996 DOI: 10.1016/j.leukres.2012.07.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 06/20/2012] [Accepted: 07/16/2012] [Indexed: 10/29/2022]
Abstract
The PRH/Hhex transcription factor represses multiple genes in the VEGF signalling pathway (VSP) to inhibit myeloid cell survival. Protein kinase CK2 phosphorylates PRH and counteracts the inhibitory effect of this protein on cell survival by blocking the repression of VSP genes. Here we show that the BCR-ABL/Src kinase inhibitor dasatinib decreases PRH phosphorylation and increases PRH-dependent repression of Vegf and Vegfr-1. Moreover in the absence of PRH, dasatinib does not inhibit cell survival as effectively as in PRH expressing cells. Thus the re-establishment of gene control by PRH is in part responsible for the therapeutic effects of dasatinib.
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Affiliation(s)
- Peter Noy
- School Immunity and Infection, University of Birmingham, Birmingham, UK
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Noy P, Sawasdichai A, Jayaraman PS, Gaston K. Protein kinase CK2 inactivates PRH/Hhex using multiple mechanisms to de-repress VEGF-signalling genes and promote cell survival. Nucleic Acids Res 2012; 40:9008-20. [PMID: 22844093 PMCID: PMC3467080 DOI: 10.1093/nar/gks687] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Protein kinase CK2 promotes cell survival and the activity of this kinase is elevated in several cancers including chronic myeloid leukaemia. We have shown previously that phosphorylation of the Proline-Rich Homeodomain protein (PRH/Hhex) by CK2 inhibits the DNA-binding activity of this transcription factor. Furthermore, PRH represses the transcription of multiple genes encoding components of the VEGF-signalling pathway and thereby influences cell survival. Here we show that the inhibitory effects of PRH on cell proliferation are abrogated by CK2 and that CK2 inhibits the binding of PRH at the Vegfr-1 promoter. Phosphorylation of PRH by CK2 also decreases the nuclear association of PRH and induces its cleavage by the proteasome. Moreover, cleavage of phosphorylated PRH produces a stable truncated cleavage product which we have termed PRHΔC (HhexΔC). PRHΔC acts as a transdominant negative regulator of full-length PRH by sequestering TLE proteins that function as PRH co-repressors. We show that this novel regulatory mechanism results in the alleviation of PRH-mediated repression of Vegfr-1. We suggest that the re-establishment of PRH function through inhibition of CK2 could be of value in treatment of myeloid leukaemias, as well as other tumour types in which PRH is inactivated by phosphorylation.
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Affiliation(s)
- Peter Noy
- Division of Immunity and Infection, School of Medicine, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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Protein kinase CK2 in hematologic malignancies: reliance on a pivotal cell survival regulator by oncogenic signaling pathways. Leukemia 2012; 26:1174-9. [PMID: 22289987 DOI: 10.1038/leu.2011.385] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
CK2 is a multitask kinase whose role is essential for a countless number of cellular processes, many of which are critical for blood cell development. A prevailing task for this kinase rests on counteracting programmed cell death triggered by multiple stimuli. CK2 is overexpressed in many solid tumors and in vivo mouse models have proven its tumorigenic potential. Recent data have suggested that CK2 may also have a significant role in the pathogenesis of hematopoietic tumors, such as multiple myeloma, chronic lymphocytic leukemia, acute myelogenous leukemia, acute lymphoblastic leukemia and chronic myeloproliferative neoplasms. CK2 regulates hematopoiesis-associated signaling pathways and seems to reinforce biochemical cascades indispensable for tumor growth, proliferation and resistance to conventional and novel cytotoxic agents. Although its activity is multifold, recent evidence supports the rationale of CK2 inhibition as a therapeutic strategy in solid and hematological tumors and phase-I clinical trials are in progress to test the efficacy of this innovative therapeutic approach. In this review, we will summarize the data supporting CK2 as an oncogenic kinase in blood tumors and we will describe some critical signaling pathways, whose regulation by this protein kinase may be implicated in tumorigenesis.
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Francis OL, Payne JL, Su RJ, Payne KJ. Regulator of myeloid differentiation and function: The secret life of Ikaros. World J Biol Chem 2011; 2:119-25. [PMID: 21765977 PMCID: PMC3135858 DOI: 10.4331/wjbc.v2.i6.119] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2011] [Revised: 05/02/2011] [Accepted: 05/09/2011] [Indexed: 02/05/2023] Open
Abstract
Ikaros (also known as Lyf-1) was initially described as a lymphoid-specific transcription factor. Although Ikaros has been shown to regulate hematopoietic stem cell renewal, as well as the development and function of cells from multiple hematopoietic lineages, including the myeloid lineage, Ikaros has primarily been studied in context of lymphoid development and malignancy. This review focuses on the role of Ikaros in myeloid cells. We address the importance of post-transcriptional regulation of Ikaros function; the emerging role of Ikaros in myeloid malignancy; Ikaros as a regulator of myeloid differentiation and function; and the selective expression of Ikaros isoform-x in cells with myeloid potential. We highlight the challenges of dissecting Ikaros function in lineage commitment decisions among lymphoid-myeloid progenitors that have emerged as a major myeloid differentiation pathway in recent studies, which leads to reconstruction of the traditional map of murine and human hematopoiesis.
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Affiliation(s)
- Olivia L Francis
- Olivia L Francis, Rui-Jun Su, Kimberly J Payne, Department of Pathology and Human Anatomy, Center for Health Disparities and Molecular Medicine, Loma Linda University School of Medicine, Mortensen Hall 1st Floor, 11085 Campus St, Loma Linda, CA 9350, United States
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Bandyopadhyay K, Gjerset RA. Protein kinase CK2 is a central regulator of topoisomerase I hyperphosphorylation and camptothecin sensitivity in cancer cell lines. Biochemistry 2011; 50:704-14. [PMID: 21182307 DOI: 10.1021/bi101110e] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Topoisomerase I (topo I) is required to unwind DNA during synthesis and provides the unique target for camptothecin-derived chemotherapeutic agents, including Irinotecan and Topotecan. While these agents are highly effective anticancer agents, some tumors do not respond due to intrinsic or acquired resistance, a process that remains poorly understood. Because of treatment toxicity, there is interest in identifying cellular factors that regulate tumor sensitivity and might serve as predictive biomarkers of therapy sensitivity. Here we identify the serine kinase, protein kinase CK2, as a central regulator of topo I hyperphosphorylation and activity and cellular sensitivity to camptothecin. In nine cancer cell lines and three normal tissue-derived cell lines we observe a consistent correlation between CK2 levels and camptothecin responsiveness. Two other topo I-targeted serine kinases, protein kinase C and cyclin-dependent kinase 1, do not show this correlation. Camptothecin-sensitive cancer cell lines display high CK2 activity, hyperphosphorylation of topo I, elevated topo I activity, and elevated phosphorylation-dependent complex formation between topo I and p14ARF, a topo I activator. Camptothecin-resistant cancer cell lines and normal cell lines display lower CK2 activity, lower topo I phosphorylation, lower topo I activity, and undetectable topo I/p14ARF complex formation. Experimental inhibition or activation of CK2 demonstrates that CK2 is necessary and sufficient for regulating these topo I properties and altering cellular responses to camptothecin. The results establish a cause and effect relationship between CK2 activity and camptothecin sensitivity and suggest that CK2, topo I phosphorylation, or topo I/p14ARF complex formation could provide biomarkers of therapy-responsive tumors.
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Affiliation(s)
- Keya Bandyopadhyay
- Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, California 92121, United States
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Barata JT. The impact of PTEN regulation by CK2 on PI3K-dependent signaling and leukemia cell survival. ACTA ACUST UNITED AC 2010; 51:37-49. [PMID: 21035501 DOI: 10.1016/j.advenzreg.2010.09.012] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 09/05/2010] [Indexed: 11/16/2022]
Abstract
Gene alterations affecting elements of PI3K signaling pathway do not appear to be sufficient to explain the extremely high frequency of PI3K signaling hyperactivation in leukemia. It has been known for long that PTEN phosphorylation at the C-terminal tail, in particular by CK2, contributes to the stabilization and simultaneous inhibition of this critical tumor suppressor. However, direct evidence of the involvement of this mechanism in cancer has been gathered only recently. It is now known that CK2-mediated posttranslational, non-deleting, inactivation of PTEN occurs in T-ALL, CLL and probably other leukemias and solid tumors. To explore this knowledge for therapeutic purposes remains one of the challenges ahead.
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Affiliation(s)
- João T Barata
- Instituto de Medicina Molecular, Faculdade de Medicina, Unversidade de Lisboa, Lisboa, Portugal.
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12
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CALLA and protein kinase CK2 revisited: targetable molecules for treating patients with leukemia? J Pediatr Hematol Oncol 2010; 32:1. [PMID: 20051778 DOI: 10.1097/mph.0b013e3181c74adf] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Pi J, Bai Y, Reece JM, Williams J, Liu D, Freeman ML, Fahl WE, Shugar D, Liu J, Qu W, Collins S, Waalkes MP. Molecular mechanism of human Nrf2 activation and degradation: role of sequential phosphorylation by protein kinase CK2. Free Radic Biol Med 2007; 42:1797-806. [PMID: 17512459 PMCID: PMC1950666 DOI: 10.1016/j.freeradbiomed.2007.03.001] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2006] [Revised: 01/25/2007] [Accepted: 03/02/2007] [Indexed: 12/15/2022]
Abstract
Nrf2 is a key transcription factor in the cellular response to oxidative stress. In this study we identify two phosphorylated forms of endogenous human Nrf2 after chemically induced oxidative stress and provide evidence that protein kinase CK2-mediated sequential phosphorylation plays potential roles in Nrf2 activation and degradation. Human Nrf2 has a predicted molecular mass of 66 kDa. However, immunoblots showed that two bands at 98 and 118 kDa, which are identified as phosphorylated forms, are increased in response to Nrf2 inducers. In addition, human Nrf2 was found to be a substrate for CK2 which mediated two steps of phosphorylation, resulting in two forms of Nrf2 migrating with differing M(r) at 98 kDa (Nrf2-98) and 118 kDa (Nrf2-118). Our results support a role in which calmodulin binding regulates CK2 activity, in that cold (25 degrees C) Ca(2+)-free media (cold/Ca(2+)-free) decreased both cellular calcium levels and CK2-calmodulin binding and induced Nrf2-118 formation, the latter of which was prevented by CK2-specific inhibitors. Gel shift assays showed that the Nrf2-118 generated under cold/Ca(2+)-free conditions does not bind to the antioxidant response element, indicating that Nrf2-98 has transcriptional activity. In contrast, Nrf2-118 is more susceptible to degradation. These results provide evidence for phosphorylation by CK2 as a critical controlling factor in Nrf2-mediated cellular antioxidant response.
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Affiliation(s)
- Jingbo Pi
- Laboratory of Comparative Carcinogenesis, NCI at NIEHS, NIH, RTP, North Carolina 27709
- Endocrine Biology Program, The Hamner Institutes for Health Sciences, RTP, North Carolina 27709
| | - Yushi Bai
- Endocrine Biology Program, The Hamner Institutes for Health Sciences, RTP, North Carolina 27709
| | - Jeffrey M. Reece
- Laboratory of Signal Transduction, NIEHS, NIH, RTP, North Carolina 27709
| | - Jason Williams
- Laboratory of Structure Biology, NIEHS, NIH, RTP, North Carolina 27709
| | - Dianxin Liu
- Laboratory of Signal Transduction, NIEHS, NIH, RTP, North Carolina 27709
| | - Michael L. Freeman
- Department of Radiation Oncology, Vanderbilt-Ingram Cancer Center, Vanderbilt University, Nashville, Tennessee 37232
| | - William E. Fahl
- McArdle Laboratory for Cancer Research, University of Wisconsin, Madison, Wisconsin, 53706
| | - David Shugar
- Institute of Biochemistry & Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Jie Liu
- Laboratory of Comparative Carcinogenesis, NCI at NIEHS, NIH, RTP, North Carolina 27709
| | - Wei Qu
- Laboratory of Comparative Carcinogenesis, NCI at NIEHS, NIH, RTP, North Carolina 27709
| | - Sheila Collins
- Endocrine Biology Program, The Hamner Institutes for Health Sciences, RTP, North Carolina 27709
| | - Michael P. Waalkes
- Laboratory of Comparative Carcinogenesis, NCI at NIEHS, NIH, RTP, North Carolina 27709
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Kamen BA. Marker turned target? A case to review neprilysin in ALL (or lessons learned at the American Association for Cancer Research Meetings, 2006). J Pediatr Hematol Oncol 2006; 28:201-2. [PMID: 16679914 DOI: 10.1097/01.mph.0000212921.16427.df] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Barton A Kamen
- Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08901, USA.
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Analysis by cell-free transcription of the liver-specific pyruvate kinase gene promoter. Mol Cell Biol 1989. [PMID: 2586516 DOI: 10.1128/mcb.9.10.4409] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A DNA fragment spanning nucleotides -183 to -4 with respect to the cap site of the rat L-type pyruvate kinase (L-PK) gene contains at least four binding sites for putative transcriptional factors: hepatocyte nuclear factor 1 (HNF1), liver factor A1 (LF-A1), nuclear factor 1 (NF1), and major late transcription factor (MLTF). This fragment was used to direct transcription of a reporter sequence (a G-free cassette) in cell extracts. This L-PK promoter was active in liver nuclear extracts, but not in extracts from nonhepatic tissues. A reduction of 50% of the activity was obtained with a deleted L-PK promoter containing only the HNF1-binding site. In contrast, deletion of the HNF1-binding site inactivated the promoter by more than 90%. These results were confirmed by titration experiments with synthetic oligonucleotides. Titration of HNF1 resulted in an 85% decrease of transcriptional activity, while titration of LF-A1 resulted in only a 40% decrease. The influence of NF1 and MLTF seemed to be marginal in this system. The proximal 5'-flanking sequence of the L-PK gene therefore appears to function in vitro as an efficient liver-specific promoter which requires the binding of the liver factor HNF1 and which is also stimulated by the binding of another liver-specific factor, LF-A1.
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Vaulont S, Puzenat N, Kahn A, Raymondjean M. Analysis by cell-free transcription of the liver-specific pyruvate kinase gene promoter. Mol Cell Biol 1989; 9:4409-15. [PMID: 2586516 PMCID: PMC362523 DOI: 10.1128/mcb.9.10.4409-4415.1989] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
A DNA fragment spanning nucleotides -183 to -4 with respect to the cap site of the rat L-type pyruvate kinase (L-PK) gene contains at least four binding sites for putative transcriptional factors: hepatocyte nuclear factor 1 (HNF1), liver factor A1 (LF-A1), nuclear factor 1 (NF1), and major late transcription factor (MLTF). This fragment was used to direct transcription of a reporter sequence (a G-free cassette) in cell extracts. This L-PK promoter was active in liver nuclear extracts, but not in extracts from nonhepatic tissues. A reduction of 50% of the activity was obtained with a deleted L-PK promoter containing only the HNF1-binding site. In contrast, deletion of the HNF1-binding site inactivated the promoter by more than 90%. These results were confirmed by titration experiments with synthetic oligonucleotides. Titration of HNF1 resulted in an 85% decrease of transcriptional activity, while titration of LF-A1 resulted in only a 40% decrease. The influence of NF1 and MLTF seemed to be marginal in this system. The proximal 5'-flanking sequence of the L-PK gene therefore appears to function in vitro as an efficient liver-specific promoter which requires the binding of the liver factor HNF1 and which is also stimulated by the binding of another liver-specific factor, LF-A1.
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Affiliation(s)
- S Vaulont
- Unité de Recherches en Génétique et Pathologie Moléculaires, INSERM U. 129-CHU Cochin, Paris, France
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