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Thomas LR, Wang Q, Grieb BC, Phan J, Foshage AM, Sun Q, Olejniczak ET, Clark T, Dey S, Lorey S, Alicie B, Howard GC, Cawthon B, Ess KC, Eischen CM, Zhao Z, Fesik SW, Tansey WP. Interaction with WDR5 promotes target gene recognition and tumorigenesis by MYC. Mol Cell 2015; 58:440-52. [PMID: 25818646 DOI: 10.1016/j.molcel.2015.02.028] [Citation(s) in RCA: 200] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 02/09/2015] [Accepted: 02/20/2015] [Indexed: 12/28/2022]
Abstract
MYC is an oncoprotein transcription factor that is overexpressed in the majority of malignancies. The oncogenic potential of MYC stems from its ability to bind regulatory sequences in thousands of target genes, which depends on interaction of MYC with its obligate partner, MAX. Here, we show that broad association of MYC with chromatin also depends on interaction with the WD40-repeat protein WDR5. MYC binds WDR5 via an evolutionarily conserved "MYC box IIIb" motif that engages a shallow, hydrophobic cleft on the surface of WDR5. Structure-guided mutations in MYC that disrupt interaction with WDR5 attenuate binding of MYC at ∼80% of its chromosomal locations and disable its ability to promote induced pluripotent stem cell formation and drive tumorigenesis. Our data reveal WDR5 as a key determinant for MYC recruitment to chromatin and uncover a tractable target for the discovery of anticancer therapies against MYC-driven tumors.
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Affiliation(s)
- Lance R Thomas
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Qingguo Wang
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Brian C Grieb
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Jason Phan
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Audra M Foshage
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Qi Sun
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Edward T Olejniczak
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Travis Clark
- VANTAGE, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Soumyadeep Dey
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Shelly Lorey
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Bethany Alicie
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Gregory C Howard
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Bryan Cawthon
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Kevin C Ess
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Christine M Eischen
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Zhongming Zhao
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA; Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Stephen W Fesik
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - William P Tansey
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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Abstract
The MYC family of proteins is a group of basic-helix-loop-helix-leucine zipper transcription factors that feature prominently in cancer. Overexpression of MYC is observed in the vast majority of human malignancies and promotes an extraordinary set of changes that impact cell proliferation, growth, metabolism, DNA replication, cell cycle progression, cell adhesion, differentiation, and metastasis. The purpose of this review is to introduce the reader to the mammalian family of MYC proteins, highlight important functional properties that endow them with their potent oncogenic potential, describe their mechanisms of action and of deregulation in cancer cells, and discuss efforts to target the unique properties of MYC, and of MYC-driven tumors, to treat cancer.
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Stem cell-specific activation of an ancestral myc protooncogene with conserved basic functions in the early metazoan Hydra. Proc Natl Acad Sci U S A 2010; 107:4051-6. [PMID: 20142507 DOI: 10.1073/pnas.0911060107] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The c-myc protooncogene encodes a transcription factor (Myc) with oncogenic potential. Myc and its dimerization partner Max are bHLH-Zip DNA binding proteins controlling fundamental cellular processes. Deregulation of c-myc leads to tumorigenesis and is a hallmark of many human cancers. We have identified and extensively characterized ancestral forms of myc and max genes from the early diploblastic cnidarian Hydra, the most primitive metazoan organism employed so far for the structural, functional, and evolutionary analysis of these genes. Hydra myc is specifically activated in all stem cells and nematoblast nests which represent the rapidly proliferating cell types of the interstitial stem cell system and in proliferating gland cells. In terminally differentiated nerve cells, nematocytes, or epithelial cells, myc expression is not detectable by in situ hybridization. Hydra max exhibits a similar expression pattern in interstitial cell clusters. The ancestral Hydra Myc and Max proteins display the principal design of their vertebrate derivatives, with the highest degree of sequence identities confined to the bHLH-Zip domains. Furthermore, the 314-amino acid Hydra Myc protein contains basic forms of the essential Myc boxes I through III. A recombinant Hydra Myc/Max complex binds to the consensus DNA sequence CACGTG with high affinity. Hybrid proteins composed of segments from the retroviral v-Myc oncoprotein and the Hydra Myc protein display oncogenic potential in cell transformation assays. Our results suggest that the principal functions of the Myc master regulator arose very early in metazoan evolution, allowing their dissection in a simple model organism showing regenerative ability but no senescence.
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Schwinkendorf D, Gallant P. The conserved Myc box 2 and Myc box 3 regions are important, but not essential, for Myc function in vivo. Gene 2009; 436:90-100. [PMID: 19248823 DOI: 10.1016/j.gene.2009.02.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Revised: 01/16/2009] [Accepted: 02/12/2009] [Indexed: 10/21/2022]
Abstract
Myc proto-oncoproteins are important regulators of growth and proliferation in development. Their functions have been evolutionarily conserved from insects to vertebrates, although the sequence conservation is limited to a few short domains. Here, we analyze the requirement for the most highly conserved domains, called Myc boxes 2 and 3 (MB2 and MB3), and for the weakly conserved N-terminus for the biological activity of the single Drosophila Myc protein in the animal in vivo. We find that a Myc mutant lacking the N-terminus retains very little activity, whereas Myc transgenes carrying a deletion of MB3 have a moderately increased ability to promote growth and apoptosis; mutation of MB2 reduces transcriptional output and the biological activities of Myc. Surprisingly though, Myc without MB2 retains enough activity to partially rescue the lethality of a Myc null mutation. Thus, although MB2 and MB3 are highly conserved in evolution, loss of either domain has comparatively mild consequences on Myc activity in vivo.
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Affiliation(s)
- D Schwinkendorf
- Zoologisches Institut, Universität Zürich, Zürich, Switzerland
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Abstract
The Myc proto-oncogenes, their binding partner Max and their antagonists from the Mad family of transcriptional repressors have been extensively analysed in vertebrates. However, members of this network are found in all animals examined so far. Several recent studies have addressed the physiological function of these proteins in invertebrate model organisms, in particular Drosophila melanogaster. This review describes the structure of invertebrate Myc/Max/Mad genes and it discusses their regulation and physiological functions, with special emphasis on their essential role in the control of cellular growth and proliferation.
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Affiliation(s)
- P Gallant
- Universität Zürich, Zoologisches Institut, Winterthurerstrasse 190, 8057 Zürich, Switzerland.
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Farina SF, Huff JL, Parsons JT. Mutations within the 5' half of the avian retrovirus MC29 v-myc gene alter or abolish transformation of chicken embryo fibroblasts and macrophages. J Virol 1992; 66:2698-708. [PMID: 1313895 PMCID: PMC241024 DOI: 10.1128/jvi.66.5.2698-2708.1992] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Avian myelocytomatosis virus MC29 induces a wide variety of neoplastic diseases in infected birds and transforms cells of the macrophage lineage as well as fibroblasts and epithelial cells. A biological and biochemical analysis, carried out on a series of in-frame insertion and deletion mutations within the gag-myc gene of MC29, revealed several mutations within the 5' portion of the v-myc gene that encode proteins either completely defective for transformation or compromised in their ability to transform chicken embryo fibroblasts but not macrophages. Mutations within the 3' end of the v-myc gene which disrupt sequences encoding the basic/helix-loop-helix region were defective for transformation of both fibroblasts and macrophages. Eight variants were cloned into the replication-competent avian expression vector RCAS. Analysis of cells infected with transformation-defective, replication-competent viruses confirmed the expression of functionally defective Myc proteins. Further, expression of the transformation defective variant dl91-137 in chicken fibroblasts inhibited subsequent transformation by wild-type MC29. The results reported herein support the hypothesis that Myc proteins function as regulators of transcription in a variety of cell types and clearly point out the necessity of putative regulatory domains within the amino-terminal half of the Myc protein.
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Affiliation(s)
- S F Farina
- Department of Microbiology and Cancer Center, University of Virginia Health Sciences Center, Charlottesville 22908
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Tikhonenko AT, Linial ML. gag as well as myc sequences contribute to the transforming phenotype of the avian retrovirus FH3. J Virol 1992; 66:946-55. [PMID: 1731115 PMCID: PMC240796 DOI: 10.1128/jvi.66.2.946-955.1992] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The avian retrovirus FH3, like MC29 and CMII, encodes a Gag-Myc fusion protein. However, the FH3-encoded protein is larger, about 145 kDa, and contains almost the entire retroviral gag gene. In contrast to the other gag-myc avian retroviruses, FH3 fails to transform fibroblasts in vitro, although macrophages are transformed both in vitro and in vivo (C. Chen, B. J. Biegalke, R. N. Eisenman, and M. L. Linial, J. Virol. 63:5092-5100, 1989). We have used the polymerase chain reaction technique to obtain a molecular clone of FH3. Sequence analysis of the FH3 myc oncogene revealed a single proline----histidine change (position 223) relative to c-myc. However, substitution of the FH3 myc sequence with the chicken c-myc sequence did not alter the transformation potential of the virus. Hence, overexpression of the proto-oncogene as a Gag-Myc retroviral protein is sufficient for macrophage, but not fibroblast, transformation. After passage of FH3 in fibroblast cultures, a virus (FH3L) that is capable of rapidly transforming fibroblasts appears. The Gag-Myc protein encoded by FH3L is smaller (ca. 130 kDa) than that encoded by the original viral stock (FH3E). Sequencing of an FH3L molecular clone revealed a 212-amino-acid deletion within the Gag portion. Using FH3E/FH3L recombinants, we have demonstrated that the ability of encoded viruses to transform fibroblasts directly correlates with the presence of this deletion. Moreover, the addition of the Gag sequence deleted from FH3L to the MC29 oncoprotein significantly reduces its transforming activity as measured by focus assay. These data suggest that the C-terminal segment of Gag attenuates the oncogenic potential of Gag-Myc fusion proteins.
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Affiliation(s)
- A T Tikhonenko
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98104-2092
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Filardo EJ, Humphries EH. An avian retrovirus expressing chicken pp59c-myc possesses weak transforming activity distinct from v-myc that may be modulated by adjacent normal cell neighbors. J Virol 1991; 65:6621-9. [PMID: 1942247 PMCID: PMC250727 DOI: 10.1128/jvi.65.12.6621-6629.1991] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We demonstrate that EF168, an avian retrovirus that expresses the chicken pp59c-myc proto-oncogene, transforms quail embryo fibroblasts in vitro. An EF168-transformed quail clone, EF168-28, containing a single provirus, synthesizes several hundred copies of c-myc RNA and expresses elevated levels of the pp59c-myc gene product. The EF168 provirus in EF168-28 was isolated as a molecular clone, and the nucleotide sequence of its c-myc allele was confirmed as identical to that of exons 2 and 3 of the chicken c-myc proto-oncogene. Extended infection of quail embryo fibroblast cultures with EF168 induced a number of in vitro transformation-associated parameters similar to those elicited by the oncogenic v-myc-encoding retrovirus MC29, including alteration of cellular morphology, anchorage-independent growth, and induction of immortalized cell lines. Despite the fact that EF168 and MC29 shared these biological activities, further analysis revealed that EF168 initiated transformation in quail embryo fibroblasts, bone marrow, or adherent peripheral blood cultures 100- to 1,000-fold less efficiently than did MC29. Further, in contrast to MC29-induced foci, EF168 foci were smaller, morphologically diffuse, and less prominent. Analysis of newly infected cells demonstrated efficient expression of EF168 viral RNA in the absence of transformation. These differences suggest that while the pp59v-myc gene product can exert dominant transforming activity on quail embryo fibroblasts, its ability to initiate transformation is distinct from that of the pp110gag-v-myc gene product encoded by MC29 and may be suppressed by adjacent nontransformed cell neighbors.
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Affiliation(s)
- E J Filardo
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas 75235-9048
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Chen C, Biegalke BJ, Eisenman RN, Linial ML. FH3, a v-myc avian retrovirus with limited transforming ability. J Virol 1989; 63:5092-100. [PMID: 2555545 PMCID: PMC251171 DOI: 10.1128/jvi.63.12.5092-5100.1989] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We have isolated a new acute avian transforming virus which contains the oncogene myc. This virus, designated FH3, was isolated after injection of a 10-day-old chick embryo with avian leukosis virus. While FH3 shares many properties with other v-myc-containing avian retroviruses, it also has several unique properties. The primary target for transformation in vitro is chicken macrophages; infection of chicken fibroblasts does not lead to complete morphological transformation. FH3 also exhibits a limited host range, in that Japanese quail macrophages and fibroblasts are infected but are not completely transformed. FH3 induces in vivo a limited tumor type if injected into 10-day-old chick embryos; only a cranial myelocytoma, which does not appear to be metastatic, can be detected. The v-myc gene of FH3 is expressed predominantly as a P145 Gag-Myc protein which is encoded by a ca. 8-kilobase genomic RNA. This FH3-encoded polyprotein is localized in the nucleus of all infected cells, whether or not they are transformed.
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Affiliation(s)
- C Chen
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98104
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