The Experts below are selected from a list of 228 Experts worldwide ranked by ideXlab platform
Jaideep Chaudhary - One of the best experts on this subject based on the ideXlab platform.
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Abstract 5455: Differential regulation of E2A (TCF3) by androgens in prostate cancer cells.
Cancer Research, 2013Co-Authors: Divya Patel, Jaideep ChaudharyAbstract:Introduction: E2A (TCF3) is a multifunctional basic helix loop helix (bHLH) Transcription Factor. E2A promotes cell differentiation, acts as a negative regulator of cell proliferation in normal cells and cancer cell lines and is required for normal B-cell development. Previous studies from our laboratory has shown that E2A expression is highly increased in prostate cancer as compared to normal prostate and that it acts as a tumor promoter in prostate cancer. Given the diverse biological pathways regulated/ influenced by E2A little is known about its regulation in prostate cancer. Experimental design: E2A expression in androgen sensitive LNCaP and insensitive C81 prostate cancer cell lines was determined by western blot after treatments with androgen receptor (AR) agonist R1881 and antagonist casodex. Putative Androgen Response Elements (ARE) were identified in the first intronic region of the E2A gene using some of the online bioinformatics tools and confirmed by Chromatin Immunoprecipitation (ChIP) with AR antibody and Luciferase reporter assays on the above mentioned cell lines after treatments with R1881 and casodex. Results: E2A expression was found to increase with the increasing aggrasiveness of prostate cancer cell lines as compared to normal prostate epithelial cell line RWPE1. When androgen responsive cell line LNCaP was treated with R1881 there was an increased expression of E2A which decreased upon treatment with antiandrogen casodex whereas the E2A expression remained unaltered upon similar treatments in androgen insensitive cell line C81. The first intronic region of the E2A gene was predicted to contain two putative ARE sites. ChIP after treatment of LNCaP and C81 cells with R1881 and casodex showed that the intronic region was bound by AR in LNCaP cells only in the presence of R1881, whereas C81 cells showed a pulldown with AR in presence as well as absence of R1881. Similar results were observed in luciferase reporter assays indicating that E2A is transactivated by AR in LNCaP cell lines whereas it is independent of androgens in C81 cell line. Furthermore, Luciferase reporter assays also confirmed that only one of the two predicted putative AREs was functionally active and responsible for the androgen mediated regulation of E2A. Conclusion: Our results indicate that E2A is differentially regulated in Prostate cancer cell lines. The increased expression of E2A and its role as a tumor promoter in prostate cancer cell lines may be contributed to its loss of androgen dependence as is evident in its progression from androgen dependent LNCaP to independent C81 cells. Acknowledgements: This study was supported by NIH/NCI RO1 CA128914 and NIH/NCRR/RCMI G12RR03062. Citation Format: Divya Patel, Jaideep Chaudhary. Differential regulation of E2A (TCF3) by androgens in prostate cancer cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5455. doi:10.1158/1538-7445.AM2013-5455
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increased expression of bhlh Transcription Factor E2A tcf3 in prostate cancer promotes proliferation and confers resistance to doxorubicin induced apoptosis
Biochemical and Biophysical Research Communications, 2012Co-Authors: Divya Patel, Jaideep ChaudharyAbstract:E2A (TCF3) is a multifunctional basic helix loop helix (bHLH), Transcription Factor. E2A regulates Transcription of target genes by homo- or heterodimerization with cell specific bHLH proteins. In general, E2A promotes cell differentiation, acts as a negative regulator of cell proliferation in normal cells and cancer cell lines and is required for normal B-cell development. Given the diverse biological pathways regulated/influenced by E2A little is known about its expression in cancer. In this study we investigated the expression of E2A in prostate cancer. Unexpectedly, E2A immuno-histochemistry demonstrated increased E2A expression in prostate cancer as compared to normal prostate. Silencing of E2A in prostate cancer cells DU145 and PC3 led to a significant reduction in proliferation due to G1 arrest that was in part mediated by increased CDKN1A(p21) and decreased Id1, Id3 and c-myc. E2A silencing in prostate cancer cell lines also resulted in increased apoptosis due to increased mitochondrial permeability and caspase 3/7 activation. Moreover, silencing of E2A increased sensitivity to doxorubicin induced apoptosis. Based on our results, we propose that E2A could be an upstream regulator of Id1 and c-Myc which are highly expressed in prostate cancer. These results for the first time demonstrate that E2A could in fact acts as a tumor promoter at least in prostate cancer.
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abstract c55 the basic helix loop helix Transcription Factor E2A is associated with prostate cancer
Cancer Research, 2012Co-Authors: Divya Patel, Jaideep ChaudharyAbstract:Introduction: E2A (TCF3) is a multifunctional basic helix loop helix (bHLH), Transcription Factor. E2A regulates Transcription of target genes by homo- or heterodimerization with other bHLH proteins such as MyoD, Mash, NeuroD and Id family of helix loop helix proteins. In general, E2A promotes cell differentiation, acts as a negative regulator of cell proliferation in normal cells and cancer cell lines and is required for normal B-cell development. Given the diverse biological pathways regulated/influenced by E2A little is known about its expression in cancer. Data mining approaches suggested that E2A is highly expressed in many cancers including prostate. Experimental design: E2A protein expression was investigated in clinical prostate tumor samples on high density tissue microarray slides by Immunohistochemistry (IHC). The expression of E2A in PCA cell lines DU145 and PC3 was temporarily silenced using E2A siRNA (sc-35245, Santa Cruz Biotechnology) and its effect on the Proliferation, cell cycle, apoptosis, mitochondrial membrane potential and caspase 3/7 activation was determined. The underlying mechanism of action of E2A was investigated by analyzing the expression of potential E2A regulated genes involved in cell cycle. Results: Consistent with increased E2A expression in prostate cancer suggested by meta-analysis, the E2A immunohistochemistry performed on prostate tissue microarrays demonstrated increased E2A expression in prostate cancer as compared to normal prostate. Silencing of E2A in prostate cancer cells DU145 and PC3 led to a significant reduction in proliferation due to G1 arrest that was in part mediated by increased CDKN1A(p21) and decreased Id1, Id3 and c-myc. E2A silencing in prostate cancer cell lines also resulted in increased apoptosis due to decrease in mitochondrial membrane permeability and increase in caspase 3/7 activity. Conclusion: Based on our results, we propose that E2A could be an upstream regulator of Id1 and c-Myc which are highly expressed in prostate cancer. These results for the first time demonstrate that E2A could in fact acts as a tumor promoter at least in prostate cancer. Acknowledgements: This study was supported by NIH/NCI RO1 CA128914 and NIH/NCRR/RCMI G12RR03062. Citation Format: Divya Patel, Jaideep Chaudhary. The basic helix loop helix Transcription Factor E2A is associated with prostate cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr C55.
Steven P Smith - One of the best experts on this subject based on the ideXlab platform.
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structural insights into taz2 domain mediated cbp p300 recruitment by transactivation domain 1 of the lymphopoietic Transcription Factor E2A
Journal of Biological Chemistry, 2020Co-Authors: Marina R Lochhead, Alexandra Brown, Alyssa C Kirlin, Seth Chitayat, Kim Munro, Jane E Findlay, George S Baillie, David P Lebrun, David N Langelaan, Steven P SmithAbstract:: The E-protein Transcription Factors guide immune cell differentiation, with E12 and E47 (hereafter called E2A) being essential for B-cell specification and maturation. E2A and the oncogenic chimera E2A-PBX1 contain three transactivation domains (ADs), with AD1 and AD2 having redundant, independent, and cooperative functions in a cell-dependent manner. AD1 and AD2 both mediate their functions by binding to the KIX domain of the histone acetyltransferase paralogues CREB-binding protein (CBP) and E1A-binding protein P300 (p300). This interaction is necessary for B-cell maturation and oncogenesis by E2A-PBX1 and occurs through conserved ϕ-x-x-ϕ-ϕ motifs (with ϕ denoting a hydrophobic amino acid) in AD1 and AD2. However, disruption of this interaction via mutation of the KIX domain in CBP/p300 does not completely abrogate binding of E2A and E2APBX1. Here, we determined that E2A-AD1 and E2A-AD2 also interact with the TAZ2 domain of CBP/p300. Characterization of the TAZ2:E2AAD1(1-37) complex indicated that E2A-AD1 adopts an α-helical structure and uses its ϕ-x-x-ϕ-ϕ motif to bind TAZ2. While this region overlapped with the KIX recognition region, key KIX-interacting E2A-AD1 residues were exposed, suggesting that E2A-AD1 could simultaneously bind both the KIX and TAZ2 domains. However, we did not detect a ternary complex involving E2A-AD1, KIX, and TAZ2 and found that E2A containing both intact AD1 and AD2 is required to bind to CBP/p300. Our findings highlight the structural plasticity and promiscuity of E2A-AD1 and suggest that E2A binds both the TAZ2 and KIX domains of CBP/p300 through AD1 and AD2.
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Structural insights into TAZ2 domain-mediated CBP/p300 recruitment by transactivation domain 1 of the lymphopoietic Transcription Factor E2A
Journal of Biological Chemistry, 2020Co-Authors: Marina R Lochhead, Alexandra Brown, Alyssa C Kirlin, Seth Chitayat, Kim Munro, Jane E Findlay, George S Baillie, David P Lebrun, David N Langelaan, Steven P SmithAbstract:: The E-protein Transcription Factors guide immune cell differentiation, with E12 and E47 (hereafter called E2A) being essential for B-cell specification and maturation. E2A and the oncogenic chimera E2A-PBX1 contain three transactivation domains (ADs), with AD1 and AD2 having redundant, independent, and cooperative functions in a cell-dependent manner. AD1 and AD2 both mediate their functions by binding to the KIX domain of the histone acetyltransferase paralogues CREB-binding protein (CBP) and E1A-binding protein P300 (p300). This interaction is necessary for B-cell maturation and oncogenesis by E2A-PBX1 and occurs through conserved ϕ-x-x-ϕ-ϕ motifs (with ϕ denoting a hydrophobic amino acid) in AD1 and AD2. However, disruption of this interaction via mutation of the KIX domain in CBP/p300 does not completely abrogate binding of E2A and E2APBX1. Here, we determined that E2A-AD1 and E2A-AD2 also interact with the TAZ2 domain of CBP/p300. Characterization of the TAZ2:E2AAD1(1-37) complex indicated that E2A-AD1 adopts an α-helical structure and uses its ϕ-x-x-ϕ-ϕ motif to bind TAZ2. While this region overlapped with the KIX recognition region, key KIX-interacting E2A-AD1 residues were exposed, suggesting that E2A-AD1 could simultaneously bind both the KIX and TAZ2 domains. However, we did not detect a ternary complex involving E2A-AD1, KIX, and TAZ2 and found that E2A containing both intact AD1 and AD2 is required to bind to CBP/p300. Our findings highlight the structural plasticity and promiscuity of E2A-AD1 and suggest that E2A binds both the TAZ2 and KIX domains of CBP/p300 through AD1 and AD2.
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Retrovirus-Mediated Expression of E2A-PBX1 Blocks Lymphoid Fate but Permits Retention of Myeloid Potential in Early Hematopoietic Progenitors.
PLOS ONE, 2015Co-Authors: Mark W. Woodcroft, Steven P Smith, Robert K. Slany, Kyster K. Nanan, Patrick Thompson, Kathrin Tyryshkin, David P LebrunAbstract:The oncogenic Transcription Factor E2A-PBX1 is expressed consequent to chromosomal translocation 1;19 and is an important oncogenic driver in cases of pre-B-cell acute lymphoblastic leukemia (ALL). Elucidating the mechanism by which E2A-PBX1 induces lymphoid leukemia would be expedited by the availability of a tractable experimental model in which enforced expression of E2A-PBX1 in hematopoietic progenitors induces pre-B-cell ALL. However, hematopoietic reconstitution of irradiated mice with bone marrow infected with E2A-PBX1-expressing retroviruses consistently gives rise to myeloid, not lymphoid, leukemia. Here, we elucidate the hematopoietic consequences of forced E2A-PBX1 expression in primary murine hematopoietic progenitors. We show that introducing E2A-PBX1 into multipotent progenitors permits the retention of myeloid potential but imposes a dense barrier to lymphoid development prior to the common lymphoid progenitor stage, thus helping to explain the eventual development of myeloid, and not lymphoid, leukemia in transplanted mice. Our findings also indicate that E2A-PBX1 enforces the aberrant, persistent expression of some genes that would normally have been down-regulated in the subsequent course of hematopoietic maturation. We show that enforced expression of one such gene, Hoxa9, a proto-oncogene associated with myeloid leukemia, partially reproduces the phenotype produced by E2A-PBX1 itself. Existing evidence suggests that the 1;19 translocation event takes place in committed B-lymphoid progenitors. However, we find that retrovirus-enforced expression of E2A-PBX1 in committed pro-B-cells results in cell cycle arrest and apoptosis. Our findings indicate that the neoplastic phenotype induced by E2A-PBX1 is determined by the developmental stage of the cell into which the oncoprotein is introduced.
Divya Patel - One of the best experts on this subject based on the ideXlab platform.
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Abstract 5455: Differential regulation of E2A (TCF3) by androgens in prostate cancer cells.
Cancer Research, 2013Co-Authors: Divya Patel, Jaideep ChaudharyAbstract:Introduction: E2A (TCF3) is a multifunctional basic helix loop helix (bHLH) Transcription Factor. E2A promotes cell differentiation, acts as a negative regulator of cell proliferation in normal cells and cancer cell lines and is required for normal B-cell development. Previous studies from our laboratory has shown that E2A expression is highly increased in prostate cancer as compared to normal prostate and that it acts as a tumor promoter in prostate cancer. Given the diverse biological pathways regulated/ influenced by E2A little is known about its regulation in prostate cancer. Experimental design: E2A expression in androgen sensitive LNCaP and insensitive C81 prostate cancer cell lines was determined by western blot after treatments with androgen receptor (AR) agonist R1881 and antagonist casodex. Putative Androgen Response Elements (ARE) were identified in the first intronic region of the E2A gene using some of the online bioinformatics tools and confirmed by Chromatin Immunoprecipitation (ChIP) with AR antibody and Luciferase reporter assays on the above mentioned cell lines after treatments with R1881 and casodex. Results: E2A expression was found to increase with the increasing aggrasiveness of prostate cancer cell lines as compared to normal prostate epithelial cell line RWPE1. When androgen responsive cell line LNCaP was treated with R1881 there was an increased expression of E2A which decreased upon treatment with antiandrogen casodex whereas the E2A expression remained unaltered upon similar treatments in androgen insensitive cell line C81. The first intronic region of the E2A gene was predicted to contain two putative ARE sites. ChIP after treatment of LNCaP and C81 cells with R1881 and casodex showed that the intronic region was bound by AR in LNCaP cells only in the presence of R1881, whereas C81 cells showed a pulldown with AR in presence as well as absence of R1881. Similar results were observed in luciferase reporter assays indicating that E2A is transactivated by AR in LNCaP cell lines whereas it is independent of androgens in C81 cell line. Furthermore, Luciferase reporter assays also confirmed that only one of the two predicted putative AREs was functionally active and responsible for the androgen mediated regulation of E2A. Conclusion: Our results indicate that E2A is differentially regulated in Prostate cancer cell lines. The increased expression of E2A and its role as a tumor promoter in prostate cancer cell lines may be contributed to its loss of androgen dependence as is evident in its progression from androgen dependent LNCaP to independent C81 cells. Acknowledgements: This study was supported by NIH/NCI RO1 CA128914 and NIH/NCRR/RCMI G12RR03062. Citation Format: Divya Patel, Jaideep Chaudhary. Differential regulation of E2A (TCF3) by androgens in prostate cancer cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5455. doi:10.1158/1538-7445.AM2013-5455
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increased expression of bhlh Transcription Factor E2A tcf3 in prostate cancer promotes proliferation and confers resistance to doxorubicin induced apoptosis
Biochemical and Biophysical Research Communications, 2012Co-Authors: Divya Patel, Jaideep ChaudharyAbstract:E2A (TCF3) is a multifunctional basic helix loop helix (bHLH), Transcription Factor. E2A regulates Transcription of target genes by homo- or heterodimerization with cell specific bHLH proteins. In general, E2A promotes cell differentiation, acts as a negative regulator of cell proliferation in normal cells and cancer cell lines and is required for normal B-cell development. Given the diverse biological pathways regulated/influenced by E2A little is known about its expression in cancer. In this study we investigated the expression of E2A in prostate cancer. Unexpectedly, E2A immuno-histochemistry demonstrated increased E2A expression in prostate cancer as compared to normal prostate. Silencing of E2A in prostate cancer cells DU145 and PC3 led to a significant reduction in proliferation due to G1 arrest that was in part mediated by increased CDKN1A(p21) and decreased Id1, Id3 and c-myc. E2A silencing in prostate cancer cell lines also resulted in increased apoptosis due to increased mitochondrial permeability and caspase 3/7 activation. Moreover, silencing of E2A increased sensitivity to doxorubicin induced apoptosis. Based on our results, we propose that E2A could be an upstream regulator of Id1 and c-Myc which are highly expressed in prostate cancer. These results for the first time demonstrate that E2A could in fact acts as a tumor promoter at least in prostate cancer.
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abstract c55 the basic helix loop helix Transcription Factor E2A is associated with prostate cancer
Cancer Research, 2012Co-Authors: Divya Patel, Jaideep ChaudharyAbstract:Introduction: E2A (TCF3) is a multifunctional basic helix loop helix (bHLH), Transcription Factor. E2A regulates Transcription of target genes by homo- or heterodimerization with other bHLH proteins such as MyoD, Mash, NeuroD and Id family of helix loop helix proteins. In general, E2A promotes cell differentiation, acts as a negative regulator of cell proliferation in normal cells and cancer cell lines and is required for normal B-cell development. Given the diverse biological pathways regulated/influenced by E2A little is known about its expression in cancer. Data mining approaches suggested that E2A is highly expressed in many cancers including prostate. Experimental design: E2A protein expression was investigated in clinical prostate tumor samples on high density tissue microarray slides by Immunohistochemistry (IHC). The expression of E2A in PCA cell lines DU145 and PC3 was temporarily silenced using E2A siRNA (sc-35245, Santa Cruz Biotechnology) and its effect on the Proliferation, cell cycle, apoptosis, mitochondrial membrane potential and caspase 3/7 activation was determined. The underlying mechanism of action of E2A was investigated by analyzing the expression of potential E2A regulated genes involved in cell cycle. Results: Consistent with increased E2A expression in prostate cancer suggested by meta-analysis, the E2A immunohistochemistry performed on prostate tissue microarrays demonstrated increased E2A expression in prostate cancer as compared to normal prostate. Silencing of E2A in prostate cancer cells DU145 and PC3 led to a significant reduction in proliferation due to G1 arrest that was in part mediated by increased CDKN1A(p21) and decreased Id1, Id3 and c-myc. E2A silencing in prostate cancer cell lines also resulted in increased apoptosis due to decrease in mitochondrial membrane permeability and increase in caspase 3/7 activity. Conclusion: Based on our results, we propose that E2A could be an upstream regulator of Id1 and c-Myc which are highly expressed in prostate cancer. These results for the first time demonstrate that E2A could in fact acts as a tumor promoter at least in prostate cancer. Acknowledgements: This study was supported by NIH/NCI RO1 CA128914 and NIH/NCRR/RCMI G12RR03062. Citation Format: Divya Patel, Jaideep Chaudhary. The basic helix loop helix Transcription Factor E2A is associated with prostate cancer [abstract]. In: Proceedings of the AACR Special Conference on Advances in Prostate Cancer Research; 2012 Feb 6-9; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2012;72(4 Suppl):Abstract nr C55.
Cornelis Murre - One of the best experts on this subject based on the ideXlab platform.
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correction corrigendum the opposing roles of the Transcription Factor E2A and its antagonist id3 that orchestrate and enforce the naive fate of t cells
Nature Immunology, 2013Co-Authors: Masaki Miyazaki, Richard R Rivera, Kazuko Miyazaki, Yasutoshi Agata, Cornelis MurreAbstract:Nat. Immunol. 12, 992–1001 (2011); published online 21 August 2011; corrected after print 25 June 2012 In the version of this article initially published, the GEO accession code for the ChIP-Seq data set was not included. The code is GSE30518. The error has been corrected in the HTML and PDF versions of the article.
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the opposing roles of the Transcription Factor E2A and its antagonist id3 that orchestrate and enforce the naive fate of t cells
Nature Immunology, 2011Co-Authors: Masaki Miyazaki, Richard R Rivera, Kazuko Miyazaki, Yasutoshi Agata, Cornelis MurreAbstract:The Transcription Factor E2A and Id proteins play antagonistic roles. Murre and colleagues show Id3 expression increases after the pre-TCR checkpoint and is required to maintain the naive T cell phenotype.
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The role of E2A-PBX1 in leukemogenesis.
Oncogene, 2001Co-Authors: Simon E Aspland, Heather Bendall, Cornelis MurreAbstract:A signi®cant number of the malignancies of the immune system are the result of nonrandom chromosomal translocations that cause either the overexpression of endogenous genes or the production of novel chimeric Factors that can promote uncontrolled cell growth and block dierentiation. Translocations which fuse the gene encoding the basic helix ± loop ± helix Transcription Factor E2A with either the gene encoding the homeodomain protein PBX1 or the bZIP protein HLF result in the generation of chimeric proteins that can cause preand pro-B cell acute lymphoblastic leukemias (ALL), respectively. What is currently known about the E2A-HLF fusion protein is reviewed elsewhere in this issue. This review focuses on the mechanisms and models of E2A-PBX1-mediated pre-B cell transformation.
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oncogenic homeodomain Transcription Factor E2A pbx1 activates a novel wnt gene in pre b acute lymphoblastoid leukemia
Proceedings of the National Academy of Sciences of the United States of America, 1999Co-Authors: John Mcwhirter, Saskia T C Neuteboom, Edward Wancewicz, Brett P Monia, James R Downing, Cornelis MurreAbstract:A large fraction of pediatric pre-B acute lymphoblastoid leukemias (ALL) consistently contain a t(1;19) chromosomal translocation. The t(1;19) translocation results in the production of a chimeric Transcription Factor containing the N-terminal transactivation domain of E2A fused to the C-terminal DNA-binding homeodomain of Pbx1. Here, we show that the E2A-Pbx1 fusion protein activates the expression of a novel WNT gene, WNT-16. WNT-16 normally is expressed in peripheral lymphoid organs such as spleen, appendix, and lymph nodes, but not in bone marrow. In contrast, high levels of WNT-16 transcripts are present in bone marrow and cell lines derived from pre-B ALL patients carrying the E2A-Pbx1 hybrid gene. Inhibition of E2A-Pbx1 expression leads to a significant decrease in WNT-16 mRNA levels, suggesting that WNT-16 is a downstream target of E2A-Pbx1. Three putative WNT receptors, FZ-2, FZ-3, and FZ-5, are expressed in cells of the B lineage, including pre-B ALL cells aberrantly expressing WNT-16. We propose that a WNT-16-mediated autocrine growth mechanism contributes to the development of t(1;19) pre-B ALL.
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A novel fibroblast growth Factor gene expressed in the developing nervous system is a downstream target of the chimeric homeodomain oncoprotein E2A-Pbx1.
Development, 1997Co-Authors: John Mcwhirter, Martyn Goulding, Joshua A. Weiner, Jerold Chun, Cornelis MurreAbstract:Pbx1 is a homeodomain Transcription Factor that has the ability to form heterodimers with homeodomain proteins encoded by the homeotic selector (Hox) gene complexes and increase their DNA-binding affinity and specificity. A current hypothesis proposes that interactions with Pbx1 are necessary for Hox proteins to regulate downstream target genes that in turn control growth, differentiation and morphogenesis during development. In pre B cell leukemias containing the t(1;19) chromosome translocation, Pbx1 is converted into a strong transactivator by fusion to the activation domain of the bHLH Transcription Factor E2A. The E2A-Pbx1 fusion protein should therefore activate Transcription of genes normally regulated by Pbx1. We have used the subtractive process of representational difference analysis to identify targets of E2A-Pbx1. We show that E2A-Pbx1 can directly activate Transcription of a novel member of the fibroblast growth Factor family of intercellular signalling molecules, FGF-15. The FGF-15 gene is expressed in a regionally restricted pattern in the developing nervous system, suggesting that FGF-15 may play an important role in regulating cell division and patterning within specific regions of the embryonic brain, spinal cord and sensory organs.
David P Lebrun - One of the best experts on this subject based on the ideXlab platform.
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structural insights into taz2 domain mediated cbp p300 recruitment by transactivation domain 1 of the lymphopoietic Transcription Factor E2A
Journal of Biological Chemistry, 2020Co-Authors: Marina R Lochhead, Alexandra Brown, Alyssa C Kirlin, Seth Chitayat, Kim Munro, Jane E Findlay, George S Baillie, David P Lebrun, David N Langelaan, Steven P SmithAbstract:: The E-protein Transcription Factors guide immune cell differentiation, with E12 and E47 (hereafter called E2A) being essential for B-cell specification and maturation. E2A and the oncogenic chimera E2A-PBX1 contain three transactivation domains (ADs), with AD1 and AD2 having redundant, independent, and cooperative functions in a cell-dependent manner. AD1 and AD2 both mediate their functions by binding to the KIX domain of the histone acetyltransferase paralogues CREB-binding protein (CBP) and E1A-binding protein P300 (p300). This interaction is necessary for B-cell maturation and oncogenesis by E2A-PBX1 and occurs through conserved ϕ-x-x-ϕ-ϕ motifs (with ϕ denoting a hydrophobic amino acid) in AD1 and AD2. However, disruption of this interaction via mutation of the KIX domain in CBP/p300 does not completely abrogate binding of E2A and E2APBX1. Here, we determined that E2A-AD1 and E2A-AD2 also interact with the TAZ2 domain of CBP/p300. Characterization of the TAZ2:E2AAD1(1-37) complex indicated that E2A-AD1 adopts an α-helical structure and uses its ϕ-x-x-ϕ-ϕ motif to bind TAZ2. While this region overlapped with the KIX recognition region, key KIX-interacting E2A-AD1 residues were exposed, suggesting that E2A-AD1 could simultaneously bind both the KIX and TAZ2 domains. However, we did not detect a ternary complex involving E2A-AD1, KIX, and TAZ2 and found that E2A containing both intact AD1 and AD2 is required to bind to CBP/p300. Our findings highlight the structural plasticity and promiscuity of E2A-AD1 and suggest that E2A binds both the TAZ2 and KIX domains of CBP/p300 through AD1 and AD2.
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Structural insights into TAZ2 domain-mediated CBP/p300 recruitment by transactivation domain 1 of the lymphopoietic Transcription Factor E2A
Journal of Biological Chemistry, 2020Co-Authors: Marina R Lochhead, Alexandra Brown, Alyssa C Kirlin, Seth Chitayat, Kim Munro, Jane E Findlay, George S Baillie, David P Lebrun, David N Langelaan, Steven P SmithAbstract:: The E-protein Transcription Factors guide immune cell differentiation, with E12 and E47 (hereafter called E2A) being essential for B-cell specification and maturation. E2A and the oncogenic chimera E2A-PBX1 contain three transactivation domains (ADs), with AD1 and AD2 having redundant, independent, and cooperative functions in a cell-dependent manner. AD1 and AD2 both mediate their functions by binding to the KIX domain of the histone acetyltransferase paralogues CREB-binding protein (CBP) and E1A-binding protein P300 (p300). This interaction is necessary for B-cell maturation and oncogenesis by E2A-PBX1 and occurs through conserved ϕ-x-x-ϕ-ϕ motifs (with ϕ denoting a hydrophobic amino acid) in AD1 and AD2. However, disruption of this interaction via mutation of the KIX domain in CBP/p300 does not completely abrogate binding of E2A and E2APBX1. Here, we determined that E2A-AD1 and E2A-AD2 also interact with the TAZ2 domain of CBP/p300. Characterization of the TAZ2:E2AAD1(1-37) complex indicated that E2A-AD1 adopts an α-helical structure and uses its ϕ-x-x-ϕ-ϕ motif to bind TAZ2. While this region overlapped with the KIX recognition region, key KIX-interacting E2A-AD1 residues were exposed, suggesting that E2A-AD1 could simultaneously bind both the KIX and TAZ2 domains. However, we did not detect a ternary complex involving E2A-AD1, KIX, and TAZ2 and found that E2A containing both intact AD1 and AD2 is required to bind to CBP/p300. Our findings highlight the structural plasticity and promiscuity of E2A-AD1 and suggest that E2A binds both the TAZ2 and KIX domains of CBP/p300 through AD1 and AD2.
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Retrovirus-Mediated Expression of E2A-PBX1 Blocks Lymphoid Fate but Permits Retention of Myeloid Potential in Early Hematopoietic Progenitors.
PLOS ONE, 2015Co-Authors: Mark W. Woodcroft, Steven P Smith, Robert K. Slany, Kyster K. Nanan, Patrick Thompson, Kathrin Tyryshkin, David P LebrunAbstract:The oncogenic Transcription Factor E2A-PBX1 is expressed consequent to chromosomal translocation 1;19 and is an important oncogenic driver in cases of pre-B-cell acute lymphoblastic leukemia (ALL). Elucidating the mechanism by which E2A-PBX1 induces lymphoid leukemia would be expedited by the availability of a tractable experimental model in which enforced expression of E2A-PBX1 in hematopoietic progenitors induces pre-B-cell ALL. However, hematopoietic reconstitution of irradiated mice with bone marrow infected with E2A-PBX1-expressing retroviruses consistently gives rise to myeloid, not lymphoid, leukemia. Here, we elucidate the hematopoietic consequences of forced E2A-PBX1 expression in primary murine hematopoietic progenitors. We show that introducing E2A-PBX1 into multipotent progenitors permits the retention of myeloid potential but imposes a dense barrier to lymphoid development prior to the common lymphoid progenitor stage, thus helping to explain the eventual development of myeloid, and not lymphoid, leukemia in transplanted mice. Our findings also indicate that E2A-PBX1 enforces the aberrant, persistent expression of some genes that would normally have been down-regulated in the subsequent course of hematopoietic maturation. We show that enforced expression of one such gene, Hoxa9, a proto-oncogene associated with myeloid leukemia, partially reproduces the phenotype produced by E2A-PBX1 itself. Existing evidence suggests that the 1;19 translocation event takes place in committed B-lymphoid progenitors. However, we find that retrovirus-enforced expression of E2A-PBX1 in committed pro-B-cells results in cell cycle arrest and apoptosis. Our findings indicate that the neoplastic phenotype induced by E2A-PBX1 is determined by the developmental stage of the cell into which the oncoprotein is introduced.
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E2A proteins enhance the histone acetyltransferase activity of the Transcriptional co-activators CBP and p300.
Biochimica et Biophysica Acta, 2012Co-Authors: Brandy D. Hyndman, Patrick Thompson, Richard Bayly, Graham P. Côté, David P LebrunAbstract:Abstract The E2A gene encodes the E-protein Transcription Factors E12 and E47 that play critical roles in B-lymphopoiesis. A somatic chromosomal translocation detectable in 5% of cases of acute lymphoblastic leukemia (ALL) involves E2A and results in expression of the oncogenic Transcription Factor E2A-PBX1. CREB binding protein (CBP) and its close paralog p300 are Transcriptional co-activators with intrinsic histone acetyltransferase (HAT) activity. We and others have shown that direct binding of an N-terminal Transcriptional activation domain present in E12/E47 and E2A-PBX1 to the KIX domain of CBP/p300 contributes to E2A protein function. In the current work we show for the first time that the catalytic HAT activity of CBP/p300 is increased in the presence of residues 1–483 of E2A (i.e., the portion present in E2A-PBX1). The addition of purified, recombinant E2A protein to in vitro assays results in a two-fold augmentation of CBP/p300 HAT activity, whereas in vivo assays show a ten-fold augmentation of HAT-dependent Transcriptional induction and a five-fold augmentation of acetylation of reporter plasmid-associated histone by CBP in response to co-transfected E2A. Our results indicate that the HAT-enhancing effect is independent of the well-documented E2A–CBP interaction involving the KIX domain and suggest a role for direct, perhaps low affinity binding of E2A to a portion of CBP that includes the HAT domain and flanking elements. Our findings add to a growing body of literature indicating that interactions between CBP/p300 and Transcription Factors can function in a specific manner to modulate HAT catalytic activity.
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Role for homodimerization in growth deregulation by E2A fusion proteins.
Molecular and Cellular Biology, 2000Co-Authors: Richard Bayly, David P LebrunAbstract:The oncogenic Transcription Factor E2A-Pbx1 is expressed in some cases of acute lymphoblastic leukemia as a result of chromosomal translocation 1;19. The early observation that E2A-Pbx1 incorporates Transcriptional activation domains from E2A and a DNA-binding homeodomain from Pbx1 inspired a model in which E2A-Pbx1 promotes leukemogenic transformation of lymphoid progenitor cells through Transcriptional induction of target genes defined by the Pbx1 portion of the molecule. However, the subsequent demonstration that the only known DNA-binding module on the molecule, the Pbx1 homeodomain, is dispensable for the induction of lymphoblastic lymphoma in transgenic mice called into question the contribution made by the Pbx1 portion. In this study, we have used a domain swap approach coupled with a fibroblast-based focus formation assay to evaluate further the requirement for PBX1-encoded peptide elements in growth deregulation by E2A-Pbx1. No impairment of focus formation was observed when the entire Pbx1 portion was replaced with DNA-binding/dimerization domains derived from yeast Transcription Factor GAL4 or GCN4. Furthermore, replacement of Pbx1 with tandem FKBP domains that mediate homodimerization in the presence of a synthetic ligand led to striking growth deregulation exclusively in the presence of the dimerizing agent. N-terminal elements encoded by E2A, including the AD1 Transcriptional activation domain, were required for dimerization-induced focus formation. We conclude that Transcriptional target genes defined by heterologous C-terminal DNA-binding modules are not required in growth deregulation by E2A fusion proteins. We speculate that interactions between N-terminal E2A elements and undefined proteins that could function as components of a Transcriptional coactivator complex may be more important.