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Liu D, Hsieh CL, Lieber MR. The RNA tether model for human chromosomal translocation fragile zones. Trends Biochem Sci 2024; 49:391-400. [PMID: 38490833 PMCID: PMC11069435 DOI: 10.1016/j.tibs.2024.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 02/06/2024] [Accepted: 02/16/2024] [Indexed: 03/17/2024]
Abstract
One of the two chromosomal breakage events in recurring translocations in B cell neoplasms is often due to the recombination-activating gene complex (RAG complex) releasing DNA ends before end joining. The other break occurs in a fragile zone of 20-600 bp in a non-antigen receptor gene locus, with a more complex and intriguing set of mechanistic factors underlying such narrow fragile zones. These factors include activation-induced deaminase (AID), which acts only at regions of single-stranded DNA (ssDNA). Recent work leads to a model involving the tethering of AID to the nascent RNA as it emerges from the RNA polymerase. This mechanism may have relevance in class switch recombination (CSR) and somatic hypermutation (SHM), as well as broader relevance for other DNA enzymes.
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Affiliation(s)
- Di Liu
- Institute of Molecular and Translational Medicine (IMTM), and Department of Biochemistry and Molecular Biology, Xi'an Jiaotong University Health Science Center, and Key Laboratory of Environment and Genes Related to Diseases, Xi'an Jiaotong University, Ministry of Education, Xi'an, Shaanxi 710061, China
| | - Chih-Lin Hsieh
- USC Norris Comprehensive Cancer Center, Department of Urology, University of Southern California, Los Angeles, CA 90089-9176, USA
| | - Michael R Lieber
- USC Norris Comprehensive Cancer Center, Departments of Pathology and Laboratory Medicine, of Molecular Microbiology and Immunology, of Biochemistry and Molecular Medicine, and in the Section of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089-9176, USA.
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2
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Watanabe G, Lieber MR. The flexible and iterative steps within the NHEJ pathway. Prog Biophys Mol Biol 2023; 180-181:105-119. [PMID: 37150451 DOI: 10.1016/j.pbiomolbio.2023.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/28/2023] [Accepted: 05/04/2023] [Indexed: 05/09/2023]
Abstract
Cellular and biochemical studies of nonhomologous DNA end joining (NHEJ) have long established that nuclease and polymerase action are necessary for the repair of a very large fraction of naturally-arising double-strand breaks (DSBs). This conclusion is derived from NHEJ studies ranging from yeast to humans and all genetically-tractable model organisms. Biochemical models derived from recent real-time and structural studies have yet to incorporate physical space or timing for DNA end processing. In real-time single molecule FRET (smFRET) studies, our lab analyzed NHEJ synapsis of DNA ends in a defined biochemical system. We described a Flexible Synapsis (FS) state in which the DNA ends were in proximity via only Ku and XRCC4:DNA ligase 4 (X4L4), and in an orientation that would not yet permit ligation until base pairing between one or more nucleotides of microhomology (MH) occurred, thereby allowing an in-line Close Synapsis (CS) state. If no MH was achievable, then XLF was critical for ligation. Neither FS or CS required DNA-PKcs, unless Artemis activation was necessary to permit local resection and subsequent base pairing between the two DNA ends being joined. Here we conjecture on possible 3D configurations for this FS state, which would spatially accommodate the nuclease and polymerase processing steps in an iterative manner. The FS model permits repeated attempts at ligation of at least one strand at the DSB after each round of nuclease or polymerase action. In addition to activation of Artemis, other possible roles for DNA-PKcs are discussed.
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Affiliation(s)
- Go Watanabe
- Departments of Pathology, Biochemistry, Molecular Microbiology & Immunology, and Section of Molecular & Computational Biology (Department of Biological Sciences), University of Southern California, Los Angeles, CA, 90089-9176, USA
| | - Michael R Lieber
- Departments of Pathology, Biochemistry, Molecular Microbiology & Immunology, and Section of Molecular & Computational Biology (Department of Biological Sciences), University of Southern California, Los Angeles, CA, 90089-9176, USA.
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Manojlovic Z, Wlodarczyk J, Okitsu C, Jin Y, Van Den Berg D, Lieber MR, Hsieh CL. Construction of high coverage whole-genome sequencing libraries from single colon crypts without DNA extraction or whole-genome amplification. BMC Res Notes 2023; 16:66. [PMID: 37106434 PMCID: PMC10142246 DOI: 10.1186/s13104-023-06333-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 04/12/2023] [Indexed: 04/29/2023] Open
Abstract
OBJECTIVE Comprehensive and reliable genome-wide variant analysis of a small number of cells has been challenging due to genome coverage bias, PCR over-cycling, and the requirement of expensive technologies. To comprehensively identify genome alterations in single colon crypts that reflect genome heterogeneity of stem cells, we developed a method to construct whole-genome sequencing libraries from single colon crypts without DNA extraction, whole-genome amplification, or increased PCR enrichment cycles. RESULTS We present post-alignment statistics of 81 single-crypts (each contains four- to eight-fold less DNA than the requirement of conventional methods) and 16 bulk-tissue libraries to demonstrate the consistent success in obtaining reliable coverage, both in depth (≥ 30X) and breadth (≥ 92% of the genome covered at ≥ 10X depth), of the human genome. These single-crypt libraries are of comparable quality as libraries generated with the conventional method using high quality and quantities of purified DNA. Conceivably, our method can be applied to small biopsy samples from many tissues and can be combined with single cell targeted sequencing to comprehensively profile cancer genomes and their evolution. The broad potential application of this method offers expanded possibilities in cost-effectively examining genome heterogeneity in small numbers of cells at high resolution.
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Affiliation(s)
- Zarko Manojlovic
- Department of Urology, University of Southern California, 1441 Eastlake Ave., NTT5420, Los Angeles, CA, USA
| | - Jordan Wlodarczyk
- Department of Surgery, University of Southern California, Los Angeles, CA, USA
| | - Cindy Okitsu
- Department of Pathology, University of Southern California, Los Angeles, CA, USA
| | - Yuxin Jin
- Department of Translational Genomics, Keck School of Medicine of USC, Los Angeles, CA, USA
| | - David Van Den Berg
- Department of Population and Public Health Sciences, University of Southern California, Los Angeles, CA, USA
| | - Michael R Lieber
- Department of Pathology, University of Southern California, Los Angeles, CA, USA
| | - Chih-Lin Hsieh
- Department of Urology, University of Southern California, 1441 Eastlake Ave., NTT5420, Los Angeles, CA, USA.
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Ogana HA, Hurwitz S, Hsieh CL, Geng H, Müschen M, Bhojwani D, Wolf MA, Larocque J, Lieber MR, Kim YM. Artemis inhibition as a therapeutic strategy for acute lymphoblastic leukemia. Front Cell Dev Biol 2023; 11:1134121. [PMID: 37082620 PMCID: PMC10111164 DOI: 10.3389/fcell.2023.1134121] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 03/20/2023] [Indexed: 04/03/2023] Open
Abstract
As effective therapies for relapse and refractory B-cell acute lymphoblastic leukemia (B-ALL) remain problematic, novel therapeutic strategies are needed. Artemis is a key endonuclease in V(D)J recombination and nonhomologous end joining (NHEJ) of DNA double-strand break (DSB) repair. Inhibition of Artemis would cause chromosome breaks during maturation of RAG-expressing T- and B-cells. Though this would block generation of new B- and T-cells temporarily, it could be oncologically beneficial for reducing the proliferation of B-ALL and T-ALL cells by causing chromosome breaks in these RAG-expressing tumor cells. Currently, pharmacological inhibition is not available for Artemis. According to gene expression analyses from 207 children with high-risk pre-B acute lymphoblastic leukemias high Artemis expression is correlated with poor outcome. Therefore, we evaluated four compounds (827171, 827032, 826941, and 825226), previously generated from a large Artemis targeted drug screen. A biochemical assay using a purified Artemis:DNA-PKcs complex shows that the Artemis inhibitors 827171, 827032, 826941, 825226 have nanomolar IC50 values for Artemis inhibition. We compared these 4 compounds to a DNA-PK inhibitor (AZD7648) in three patient-derived B-ALL cell lines (LAX56, BLQ5 and LAX7R) and in two mature B-cell lines (3301015 and 5680001) as controls. We found that pharmacological Artemis inhibition substantially decreases proliferation of B-ALL cell lines while normal mature B-cell lines are not markedly affected. Inhibition of DNA-PKcs (which regulates Artemis) using the DNA-PK inhibitor AZD7648 had minor effects on these same primary patient-derived ALL lines, indicating that inhibition of V(D)J hairpin opening requires direct inhibition of Artemis, rather than indirect suppression of the kinase that regulates Artemis. Our data provides a basis for further evaluation of pharmacological Artemis inhibition of proliferation of B- and T-ALL.
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Affiliation(s)
- Heather A. Ogana
- Department of Pediatrics, Children’s Hospital Los Angeles, Division of Hematology and Oncology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Samantha Hurwitz
- Department of Pediatrics, Children’s Hospital Los Angeles, Division of Hematology and Oncology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Chih-Lin Hsieh
- Department of Urology, USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Huimin Geng
- Department of Laboratory Medicine, UCSF, San Francisco, CA, United States
| | - Markus Müschen
- Department of Immunobiology, Center of Molecular and Cellular Oncology, Yale University, New Haven, CT, United States
| | - Deepa Bhojwani
- Department of Pediatrics, Children’s Hospital Los Angeles, Division of Hematology and Oncology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | | | | | - Michael R. Lieber
- Departments of Pathology, The Molecular and Computational Biology Section of the Department of Biological Sciences, USC Norris Comprehensive Cancer Center, Biochemistry and Molecular Biology, Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
| | - Yong Mi Kim
- Department of Pediatrics, Children’s Hospital Los Angeles, Division of Hematology and Oncology, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States
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Lieber MR. Pol X DNA polymerases contribute to NHEJ flexibility. Nat Struct Mol Biol 2023; 30:5-8. [PMID: 36587186 PMCID: PMC9940989 DOI: 10.1038/s41594-022-00904-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
New work on DNA polymerase λ highlights its remarkable flexibility. This fits with the generally adaptable nature of the DNA-repair process in which this enzyme is involved — nonhomologous end-joining — which allows this mechanism to handle diverse types of broken DNA ends in order to restore the duplex structure, albeit with a loss of information at the join.
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Watanabe G, Lieber MR. Dynamics of the Artemis and DNA-PKcs Complex in the Repair of Double-Strand Breaks. J Mol Biol 2022; 434:167858. [PMID: 36270581 PMCID: PMC9940633 DOI: 10.1016/j.jmb.2022.167858] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/11/2022] [Accepted: 10/11/2022] [Indexed: 11/05/2022]
Abstract
Pathologic chromosome breaks occur in human dividing cells ∼10 times per day, and physiologic breaks occur in each lymphoid cell many additional times per day. Nonhomologous DNA end joining (NHEJ) is the major pathway for the repair of all of these double-strand breaks (DSBs) during most of the cell cycle. Nearly all broken DNA ends require trimming before they can be suitable for joining by ligation. Artemis is the major nuclease for this purpose. Artemis is tightly regulated by one of the largest protein kinases, which tethers Artemis to its surface. This kinase is called DNA-dependent protein kinase catalytic subunit (or DNA-PKcs) because it is only active when it encounters a broken DNA end. With this activation, DNA-PKcs permits the Artemis catalytic domain to enter a large cavity in the center of DNA-PKcs. Given this remarkably tight supervision of Artemis by DNA-PKcs, it is an appropriate time to ask what we know about the Artemis:DNA-PKcs complex, as we integrate recent structural information with the biochemistry of the complex and how this relates to other NHEJ proteins and to V(D)J recombination in the immune system.
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Affiliation(s)
- Go Watanabe
- Department of Pathology, Department of Biochemistry & Molecular Biology, Department of Molecular Microbiology & Immunology, and Section of Molecular & Computational Biology, USC Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1441 Eastlake Ave, Rm. 5428, Los Angeles, CA 90089, USA
| | - Michael R Lieber
- Department of Pathology, Department of Biochemistry & Molecular Biology, Department of Molecular Microbiology & Immunology, and Section of Molecular & Computational Biology, USC Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1441 Eastlake Ave, Rm. 5428, Los Angeles, CA 90089, USA.
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7
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Anne-Esguerra Z, Wu M, Watanabe G, Flint AJ, Lieber MR. Partial deletions of the autoregulatory C-terminal domain of Artemis and their effect on its nuclease activity. DNA Repair (Amst) 2022; 120:103422. [PMID: 36332285 PMCID: PMC9691611 DOI: 10.1016/j.dnarep.2022.103422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/17/2022] [Accepted: 10/26/2022] [Indexed: 11/29/2022]
Abstract
Artemis is a 692 aa nuclease that is essential for opening hairpins during vertebrate V(D)J recombination. Artemis is also important in the DNA repair of double-strand breaks via the nonhomologous DNA end joining (NHEJ) pathway. Therefore, absence of Artemis has been shown to result not only in the blockage of lymphocyte development in vertebrates, but also sensitivity of organisms and cells to double-strand break-inducing events that arise in the course of normal metabolism. Nonhomologous DNA end joining (NHEJ) is the major pathway for the repair of double-strand DNA breaks in most vertebrate cells during most of the cell cycle, including in resting cells. Artemis is the primary nuclease for resection of damaged DNA at double-strand breaks. Artemis alone is inactive as an endonuclease, though it has 5'-exonuclease activity. The endonuclease activity requires physical interaction with DNA-PKcs and subsequent activation steps. Truncation of the C-terminal half of Artemis permits Artemis to be active, even without DNA-PKcs. Here we create a systematic set of deletions from the Artemis C-terminus to determine the minimal extent of C-terminal deletion for Artemis to function in a DNA-PKcs-independent manner. We discuss these data in the context of recent structural studies. The results will be useful in future studies to determine the full range of functions of the C-terminal region of Artemis in the regulation of its endonuclease activity.
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Affiliation(s)
- Z Anne-Esguerra
- Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology, and the Section of Molecular & Computational Biology in the Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA 90033, USA
| | - Mousheng Wu
- Department of Chemistry, Drug Discovery Division, Southern Research Institute Birmingham, AL, USA
| | - Go Watanabe
- Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology, and the Section of Molecular & Computational Biology in the Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA 90033, USA
| | | | - Michael R Lieber
- Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology, and the Section of Molecular & Computational Biology in the Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA 90033, USA.
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8
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Watanabe G, Lieber MR, Williams DR. Structural analysis of the basal state of the Artemis:DNA-PKcs complex. Nucleic Acids Res 2022; 50:7697-7720. [PMID: 35801871 PMCID: PMC9303282 DOI: 10.1093/nar/gkac564] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 06/05/2022] [Accepted: 06/17/2022] [Indexed: 01/17/2023] Open
Abstract
Artemis nuclease and DNA-dependent protein kinase catalytic subunit (DNA-PKcs) are key components in nonhomologous DNA end joining (NHEJ), the major repair mechanism for double-strand DNA breaks. Artemis activation by DNA-PKcs resolves hairpin DNA ends formed during V(D)J recombination. Artemis deficiency disrupts development of adaptive immunity and leads to radiosensitive T- B- severe combined immunodeficiency (RS-SCID). An activated state of Artemis in complex with DNA-PK was solved by cryo-EM recently, which showed Artemis bound to the DNA. Here, we report that the pre-activated form (basal state) of the Artemis:DNA-PKcs complex is stable on an agarose-acrylamide gel system, and suitable for cryo-EM structural analysis. Structures show that the Artemis catalytic domain is dynamically positioned externally to DNA-PKcs prior to ABCDE autophosphorylation and show how both the catalytic and regulatory domains of Artemis interact with the N-HEAT and FAT domains of DNA-PKcs. We define a mutually exclusive binding site for Artemis and XRCC4 on DNA-PKcs and show that an XRCC4 peptide disrupts the Artemis:DNA-PKcs complex. All of the findings are useful in explaining how a hypomorphic L3062R missense mutation of DNA-PKcs could lead to insufficient Artemis activation, hence RS-SCID. Our results provide various target site candidates to design disruptors for Artemis:DNA-PKcs complex formation.
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Affiliation(s)
- Go Watanabe
- Department of Pathology, Department of Biochemistry & Molecular Biology, Department of Molecular Microbiology & Immunology, and Section of Computational & Molecular Biology, USC Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1441 Eastlake Ave, Rm. 5428, Los Angeles, CA 90089, USA
| | - Michael R Lieber
- Department of Pathology, Department of Biochemistry & Molecular Biology, Department of Molecular Microbiology & Immunology, and Section of Computational & Molecular Biology, USC Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1441 Eastlake Ave, Rm. 5428, Los Angeles, CA 90089, USA
| | - Dewight R Williams
- Eyring Materials Center, John Cowley Center for High Resolution Electron Microscopy, Arizona State University, Tempe, AZ 85281, USA
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Liu D, Goodman MF, Pham P, Yu K, Hsieh CL, Lieber MR. The mRNA tether model for activation-induced deaminase and its relevance for Ig somatic hypermutation and class switch recombination. DNA Repair (Amst) 2022; 110:103271. [PMID: 34990960 PMCID: PMC8816865 DOI: 10.1016/j.dnarep.2021.103271] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 12/19/2021] [Accepted: 12/28/2021] [Indexed: 02/03/2023]
Abstract
Activation-induced deaminase (AID) only deaminates cytosine within single-stranded DNA. Transcription is known to increase AID deamination on duplex DNA substrates during transcription. Using a purified T7 RNA polymerase transcription system, we recently found that AID deamination of a duplex DNA substrate is reduced if RNase A is added during transcription. This finding prompted us to consider that the mRNA tail may contribute to AID action at the nearby transcribed strand (TS) or non-transcribed strand (NTS) of DNA, which are transiently single-stranded in the wake of RNA polymerase movement. Here, we used a purified system to test whether a single-stranded oligonucleotide (oligo) consisting of RNA in the 5' portion and DNA in the 3' portion (i.e., 5'RNA-DNA3', also termed an RNA-DNA fusion substrate) could be deaminated equally efficiently as the same sequence when it is entirely DNA. We found that AID acts on the RNA-DNA fusion substrate and the DNA-only substrate with similar efficiency. Based on this finding and our recent observation on the importance of the mRNA tail, we propose a model in which the proximity and length of the mRNA tail provide a critical site for AID loading to permit a high local collision frequency with the NTS and TS in the transient wake of the RNA polymerase. When the mRNA tail is not present, we know that AID action drops to levels equivalent to when there is no transcription at all. This mRNA tether model explains several local and global features of Ig somatic hypermutation and Ig class switch recombination, while integrating structural and functional features of AID.
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Affiliation(s)
- Di Liu
- Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology, and the Section of Molecular & Computational Biology in the Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA 90033
| | - Myron F. Goodman
- Department of Biological Sciences (Section of Molecular & Computational Biology), University of Southern California, Los Angeles, CA 90089
| | - Phuong Pham
- Department of Biological Sciences (Section of Molecular & Computational Biology), University of Southern California, Los Angeles, CA 90089
| | - Kefei Yu
- Microbiology and Molecular Genetics, Michigan State University, 5175 Biomedical Physical Sciences, East Lansing, MI 48824
| | - Chih-Lin Hsieh
- USC Norris Comprehensive Cancer Center, Department of Urology, University of Southern California and USC Keck School of Medicine, Los Angeles, CA 90033
| | - Michael R. Lieber
- Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology, and the Section of Molecular & Computational Biology in the Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA 90033,Corresponding author: M. Lieber, , ph. 323 865 0568
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Abstract
The most common human lymphoid chromosomal translocations involve concurrent failures of the recombination activating gene (RAG) complex and Activation-Induced Deaminase (AID). These are two enzymes that are normally expressed for purposes of the two site-specific DNA recombination processes: V(D)J recombination and class switch recombination (CSR). First, though it is rare, a low level of expression of AID can introduce long-lived T:G mismatch lesions at 20-600 bp fragile zones. Second, the V(D)J recombination process can occasionally fail to rejoin coding ends, and this failure may permit an opportunity for Artemis:DNA-dependent kinase catalytic subunit (DNA-PKcs) to convert the T:G mismatch sites at the fragile zones into double-strand breaks. The 20-600 bp fragile zones must be, at least transiently, in a single-stranded DNA (ssDNA) state for the first step to occur, because AID only acts on ssDNA. Here we discuss the key DNA sequence features that lead to AID action at a fragile zone, which are (a) the proximity and density of strings of cytosine nucleotides (C-strings) that cause a B/A-intermediate DNA conformation; (b) overlapping AID hotspots that contain a methyl CpG (WRCG), which AID converts to a long-lived T:G mismatch; and (c) transcription, which, though not essential, favors increased ssDNA in the fragile zone. We also summarize chromosomal features of the focal fragile zones in lymphoid malignancies and discuss the clinical relevance of understanding the translocation mechanisms. Many of the key principles covered here are also relevant to chromosomal translocations in non-lymphoid somatic cells as well.
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Affiliation(s)
- Di Liu
- Department of Pathology & Laboratory Medicine, Department of Biochemistry & Molecular Biology, Department of Molecular Microbiology and Immunology, and Section of Computational Biology in the Department of Biological Sciences, USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Michael R Lieber
- Department of Pathology & Laboratory Medicine, Department of Biochemistry & Molecular Biology, Department of Molecular Microbiology and Immunology, and Section of Computational Biology in the Department of Biological Sciences, USC Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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11
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Ruan Y, Kim HN, Ogana HA, Wan Z, Hurwitz S, Nichols C, Abdel-Azim N, Coba A, Seo S, Loh YHE, Gang EJ, Abdel-Azim H, Hsieh CL, Lieber MR, Parekh C, Pal D, Bhojwani D, Durden DL, Kim YM. Preclinical Evaluation of a Novel Dual Targeting PI3Kδ/BRD4 Inhibitor, SF2535, in B-Cell Acute Lymphoblastic Leukemia. Front Oncol 2021; 11:766888. [PMID: 34926269 PMCID: PMC8671162 DOI: 10.3389/fonc.2021.766888] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/11/2021] [Indexed: 12/20/2022] Open
Abstract
The PI3K/Akt pathway—and in particular PI3Kδ—is known for its role in drug resistant B-cell acute lymphoblastic leukemia (B-ALL) and it is often upregulated in refractory or relapsed B-ALL. Myc proteins are transcription factors responsible for transcribing pro-proliferative genes and c-Myc is often overexpressed in cancers. The chromatin regulator BRD4 is required for expression of c-Myc in hematologic malignancies including B-ALL. Previously, combination of BRD4 and PI3K inhibition with SF2523 was shown to successfully decrease Myc expression. However, the underlying mechanism and effect of dual inhibition of PI3Kδ/BRD4 in B-ALL remains unknown. To study this, we utilized SF2535, a novel small molecule dual inhibitor which can specifically target the PI3Kδ isoform and BRD4. We treated primary B-ALL cells with various concentrations of SF2535 and studied its effect on specific pharmacological on-target mechanisms such as apoptosis, cell cycle, cell proliferation, and adhesion molecules expression usingin vitro and in vivo models. SF2535 significantly downregulates both c-Myc mRNA and protein expression through inhibition of BRD4 at the c-Myc promoter site and decreases p-AKT expression through inhibition of the PI3Kδ/AKT pathway. SF2535 induced apoptosis in B-ALL by downregulation of BCL-2 and increased cleavage of caspase-3, caspase-7, and PARP. Moreover, SF2535 induced cell cycle arrest and decreased cell counts in B-ALL. Interestingly, SF2535 decreased the mean fluorescence intensity (MFI) of integrin α4, α5, α6, and β1 while increasing MFI of CXCR4, indicating that SF2535 may work through inside-out signaling of integrins. Taken together, our data provide a rationale for the clinical evaluation of targeting PI3Kδ/BRD4 in refractory or relapsed B-ALL using SF2535.
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Affiliation(s)
- Yongsheng Ruan
- Department of Pediatrics, Division of Hematology, Oncology, Blood and Marrow Transplantation, Children’s Hospital Los Angeles, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, United States
- Department of Pediatrics, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Hye Na Kim
- Department of Pediatrics, Division of Hematology, Oncology, Blood and Marrow Transplantation, Children’s Hospital Los Angeles, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, United States
| | - Heather A. Ogana
- Department of Pediatrics, Division of Hematology, Oncology, Blood and Marrow Transplantation, Children’s Hospital Los Angeles, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, United States
| | - Zesheng Wan
- Department of Pediatrics, Division of Hematology, Oncology, Blood and Marrow Transplantation, Children’s Hospital Los Angeles, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, United States
| | - Samantha Hurwitz
- Department of Pediatrics, Division of Hematology, Oncology, Blood and Marrow Transplantation, Children’s Hospital Los Angeles, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, United States
| | - Cydney Nichols
- Department of Pediatrics, Division of Hematology, Oncology, Blood and Marrow Transplantation, Children’s Hospital Los Angeles, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, United States
| | - Nour Abdel-Azim
- Department of Pediatrics, Division of Hematology, Oncology, Blood and Marrow Transplantation, Children’s Hospital Los Angeles, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, United States
| | - Ariana Coba
- Department of Pediatrics, Division of Hematology, Oncology, Blood and Marrow Transplantation, Children’s Hospital Los Angeles, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, United States
| | - Seyoung Seo
- Department of Pediatrics, Division of Hematology, Oncology, Blood and Marrow Transplantation, Children’s Hospital Los Angeles, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, United States
| | - Yong-Hwee Eddie Loh
- University of Southern California (USC) Libraries Bioinformatics Services, University of Southern California, Los Angeles, CA, United States
| | - Eun Ji Gang
- Department of Pediatrics, Division of Hematology, Oncology, Blood and Marrow Transplantation, Children’s Hospital Los Angeles, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, United States
| | - Hisham Abdel-Azim
- Department of Pediatrics, Division of Hematology, Oncology, Blood and Marrow Transplantation, Children’s Hospital Los Angeles, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, United States
| | - Chih-Lin Hsieh
- University of Southern California (USC) Department of Urology, University of Southern California (USC) Norris Comprehensive Cancer Center, Los Angeles, CA, United States
| | - Michael R. Lieber
- University of Southern California (USC) Department of Pathology, University of Southern California (USC) Norris Comprehensive Cancer Center, Los Angeles, CA, United States
| | - Chintan Parekh
- Department of Pediatrics, Division of Hematology, Oncology, Blood and Marrow Transplantation, Children’s Hospital Los Angeles, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, United States
| | - Dhananjaya Pal
- Department of Pediatrics, University of California San Diego, San Diego, CA, United States
| | - Deepa Bhojwani
- Department of Pediatrics, Division of Hematology, Oncology, Blood and Marrow Transplantation, Children’s Hospital Los Angeles, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, United States
| | - Donald L. Durden
- Department of Pediatrics, University of California San Diego, San Diego, CA, United States
- SignalRx Pharmaceuticals Inc., Omaha, NE, United States
| | - Yong-Mi Kim
- Department of Pediatrics, Division of Hematology, Oncology, Blood and Marrow Transplantation, Children’s Hospital Los Angeles, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, United States
- *Correspondence: Yong-Mi Kim,
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12
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Liu D, Loh YHE, Hsieh CL, Lieber MR. Mechanistic basis for chromosomal translocations at the E2A gene and its broader relevance to human B cell malignancies. Cell Rep 2021; 36:109387. [PMID: 34260910 PMCID: PMC8327686 DOI: 10.1016/j.celrep.2021.109387] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 03/31/2021] [Accepted: 06/21/2021] [Indexed: 11/22/2022] Open
Abstract
Analysis of translocation breakpoints in human B cell malignancies reveals that DNA double-strand breaks at oncogenes most frequently occur at CpG sites located within 20-600 bp fragile zones and depend on activation-induced deaminase (AID). AID requires single-stranded DNA (ssDNA) to act, but it has been unclear why or how this region transiently acquires a ssDNA state. Here, we demonstrate the ssDNA state in the 23 bp E2A fragile zone using several methods, including native bisulfite DNA structural analysis in live human pre-B cells. AID deamination within the E2A fragile zone does not require but is increased upon transcription. High C-string density, nascent RNA tails, and direct DNA sequence repeats prolong the ssDNA state of the E2A fragile zone and increase AID deamination at overlapping AID hotspots that contain the CpG sites at which breaks occur in patients. These features provide key insights into lymphoid fragile zones generally.
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Affiliation(s)
- Di Liu
- Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology, and Section of Molecular & Computational Biology (Department of Biological Sciences), USC Norris Comprehensive Cancer Center, University of Southern California and USC Keck School of Medicine, Los Angeles, CA, USA
| | - Yong-Hwee Eddie Loh
- USC Libraries Bioinformatics Services, University of Southern California and USC Keck School of Medicine, Los Angeles, CA, USA
| | - Chih-Lin Hsieh
- Department of Urology, USC Norris Comprehensive Cancer Center, University of Southern California and USC Keck School of Medicine, Los Angeles, CA, USA
| | - Michael R Lieber
- Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology, and Section of Molecular & Computational Biology (Department of Biological Sciences), USC Norris Comprehensive Cancer Center, University of Southern California and USC Keck School of Medicine, Los Angeles, CA, USA.
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13
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Zhao B, Naila T, Lieber MR, Tomkinson AE. NAD+ is not utilized as a co-factor for DNA ligation by human DNA ligase IV. Nucleic Acids Res 2020; 48:12746-12750. [PMID: 33264406 PMCID: PMC7736778 DOI: 10.1093/nar/gkaa1118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/29/2020] [Accepted: 11/27/2020] [Indexed: 02/05/2023] Open
Abstract
As nucleotidyl transferases, formation of a covalent enzyme-adenylate intermediate is a common first step of all DNA ligases. While it has been shown that eukaryotic DNA ligases utilize ATP as the adenylation donor, it was recently reported that human DNA ligase IV can also utilize NAD+ and, to a lesser extent ADP-ribose, as the source of the adenylate group and that NAD+, unlike ATP, enhances ligation by supporting multiple catalytic cycles. Since this unexpected finding has significant implications for our understanding of the mechanisms and regulation of DNA double strand break repair, we attempted to confirm that NAD+ and ADP-ribose can be used as co-factors by human DNA ligase IV. Here, we provide evidence that NAD+ does not enhance ligation by pre-adenylated DNA ligase IV, indicating that this co-factor is not utilized for re-adenylation and subsequent cycles of ligation. Moreover, we find that ligation by de-adenylated DNA ligase IV is dependent upon ATP not NAD+ or ADP-ribose. Thus, we conclude that human DNA ligase IV cannot use either NAD+ or ADP-ribose as adenylation donor for ligation.
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Affiliation(s)
- Bailin Zhao
- Department of Pathology, Biochemistry and Molecular Biology, Molecular Microbiology and Immunology, and Section of Computational and Molecular Biology, USC Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1441 Eastlake Ave, Rm. 5428, Los Angeles, CA 90089, USA
| | - Tasmin Naila
- Department of Internal Medicine and Molecular Genetics and Microbiology, and the University of New Mexico Comprehensive Cancer Center, University of New Mexico, 915 Camino de Salud, Albuquerque, NM 87131, USA
| | - Michael R Lieber
- Department of Pathology, Biochemistry and Molecular Biology, Molecular Microbiology and Immunology, and Section of Computational and Molecular Biology, USC Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1441 Eastlake Ave, Rm. 5428, Los Angeles, CA 90089, USA
| | - Alan E Tomkinson
- Department of Internal Medicine and Molecular Genetics and Microbiology, and the University of New Mexico Comprehensive Cancer Center, University of New Mexico, 915 Camino de Salud, Albuquerque, NM 87131, USA
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14
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Hsieh CL, Okitsu CY, Lieber MR. Temporally uncoupled signal and coding joint formation in human V(D)J recombination. Mol Immunol 2020; 128:227-234. [PMID: 33157352 DOI: 10.1016/j.molimm.2020.10.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 09/23/2020] [Accepted: 10/14/2020] [Indexed: 11/28/2022]
Abstract
In vertebrate antigen receptor gene rearrangement, V(D)J recombination events can occur by deletion or by inversion. For deletional events, the signal joint is deleted from the genome. Nearly half of the immunoglobulin light chain genes undergo V(D)J recombination in an inversional manner, and both signal and coding joint formation must occur to retain chromosomal integrity. But given the undetermined amount of pre-B and pre-T cell death that occurs during V(D)J recombination, the efficiency with which both joints are completed is not known, nor is the relative efficiency (balance) of signal versus coding joint formation. Signal joint formation only requires Ku and XRCC4:DNA ligase 4 of the nonhomologous DNA end joining repair pathway. Coding joint formation requires these proteins as well, but in addition requires Artemis and DNA-dependent protein kinase to open the hairpin DNA coding ends, which the RAG complex generated; and further processing is required because the hairpin opening generates incompatible 3' overhangs. Mutations in some of the end processing enzymes affect one, but only minimally the other joint. We have devised a precise cellular assay that does not have any cellular, enzymatic or biochemical selective bias to assess signal and coding joint formation independently, and it can detect intermediates for which one joint has formed but not the other. We find that intermediates with only one completed joint are more abundant than molecules with both joints completed. This indicates that either joint can form independent of the other and joint formation can be a relatively slow process.
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Affiliation(s)
- Chih-Lin Hsieh
- USC Norris Comprehensive Cancer Ctr., Department of Urology, Los Angeles, CA, 90089, United States
| | - Cindy Y Okitsu
- USC Norris Comprehensive Cancer Ctr., Department of Urology, Los Angeles, CA, 90089, United States
| | - Michael R Lieber
- USC Norris Comprehensive Cancer Ctr., Departments of Pathology, Biochemistry & Molecular Biology, Molecular Microbiology & Immunology, University of Southern California Keck School of Medicine, Molecular and Computational Biology Program, Department of Biological Sciences, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA, 90089-9176, United States.
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15
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Zhao B, Watanabe G, Lieber MR. Polymerase μ in non-homologous DNA end joining: importance of the order of arrival at a double-strand break in a purified system. Nucleic Acids Res 2020; 48:3605-3618. [PMID: 32052035 PMCID: PMC7144918 DOI: 10.1093/nar/gkaa094] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/14/2020] [Accepted: 02/04/2020] [Indexed: 01/07/2023] Open
Abstract
During non-homologous DNA end joining (NHEJ), bringing two broken dsDNA ends into proximity is an essential prerequisite for ligation by XRCC4:Ligase IV (X4L4). This physical juxtaposition of DNA ends is called NHEJ synapsis. In addition to the key NHEJ synapsis proteins, Ku, X4L4, and XLF, it has been suggested that DNA polymerase mu (pol μ) may also align two dsDNA ends into close proximity for synthesis. Here, we directly observe the NHEJ synapsis by pol μ using a single molecule FRET (smFRET) assay where we can measure the duration of the synapsis. The results show that pol μ alone can mediate efficient NHEJ synapsis of 3′ overhangs that have at least 1 nt microhomology. The abundant Ku protein in cells limits the accessibility of pol μ to DNA ends with overhangs. But X4L4 can largely reverse the Ku inhibition, perhaps by pushing the Ku inward to expose the overhang for NHEJ synapsis. Based on these studies, the mechanistic flexibility known to exist at other steps of NHEJ is now also apparent for the NHEJ synapsis step.
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Affiliation(s)
- Bailin Zhao
- Department of Pathology, Department of Biochemistry & Molecular Biology, Department of Molecular Microbiology & Immunology, and Section of Computational & Molecular Biology, USC Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1441 Eastlake Ave, Rm. 5428, Los Angeles, CA 90089, USA
| | - Go Watanabe
- Department of Pathology, Department of Biochemistry & Molecular Biology, Department of Molecular Microbiology & Immunology, and Section of Computational & Molecular Biology, USC Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1441 Eastlake Ave, Rm. 5428, Los Angeles, CA 90089, USA
| | - Michael R Lieber
- Department of Pathology, Department of Biochemistry & Molecular Biology, Department of Molecular Microbiology & Immunology, and Section of Computational & Molecular Biology, USC Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1441 Eastlake Ave, Rm. 5428, Los Angeles, CA 90089, USA
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16
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Karim MF, Liu S, Laciak AR, Volk L, Koszelak-Rosenblum M, Lieber MR, Wu M, Curtis R, Huang NN, Carr G, Zhu G. Structural analysis of the catalytic domain of Artemis endonuclease/SNM1C reveals distinct structural features. J Biol Chem 2020; 295:12368-12377. [PMID: 32576658 PMCID: PMC7458816 DOI: 10.1074/jbc.ra120.014136] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/22/2020] [Indexed: 12/31/2022] Open
Abstract
The endonuclease Artemis is responsible for opening DNA hairpins during V(D)J recombination and for processing a subset of pathological DNA double-strand breaks. Artemis is an attractive target for the development of therapeutics to manage various B cell and T cell tumors, because failure to open DNA hairpins and accumulation of chromosomal breaks may reduce the proliferation and viability of pre-T and pre-B cell derivatives. However, structure-based drug discovery of specific Artemis inhibitors has been hampered by a lack of crystal structures. Here, we report the structure of the catalytic domain of recombinant human Artemis. The catalytic domain displayed a polypeptide fold similar overall to those of other members in the DNA cross-link repair gene SNM1 family and in mRNA 3′-end-processing endonuclease CPSF-73, containing metallo-β-lactamase and β-CASP domains and a cluster of conserved histidine and aspartate residues capable of binding two metal atoms in the catalytic site. As in SNM1A, only one zinc ion was located in the Artemis active site. However, Artemis displayed several unique features. Unlike in other members of this enzyme class, a second zinc ion was present in the β-CASP domain that leads to structural reorientation of the putative DNA-binding surface and extends the substrate-binding pocket to a new pocket, pocket III. Moreover, the substrate-binding surface exhibited a dominant and extensive positive charge distribution compared with that in the structures of SNM1A and SNM1B, presumably because of the structurally distinct DNA substrate of Artemis. The structural features identified here may provide opportunities for designing selective Artemis inhibitors.
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Affiliation(s)
- Md Fazlul Karim
- Discovery Biology, Albany Molecular Research Inc., Buffalo, New York, USA
| | - Shanshan Liu
- Discovery Biology, Albany Molecular Research Inc., Buffalo, New York, USA
| | - Adrian R Laciak
- Discovery Biology, Albany Molecular Research Inc., Buffalo, New York, USA
| | - Leah Volk
- Discovery Biology, Albany Molecular Research Inc., Buffalo, New York, USA
| | | | - Michael R Lieber
- USC Norris Comprehensive Cancer Center, Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology, and the Molecular and Computational Biology Section of the Department of Biological Sciences, University of Southern California Keck School of Medicine, Los Angeles, California, USA
| | - Mousheng Wu
- Chemistry Department, Drug Discovery Division, Southern Research, Birmingham, Alabama, USA
| | - Rory Curtis
- Discovery Biology, Albany Molecular Research Inc., Buffalo, New York, USA
| | - Nian N Huang
- Discovery Biology, Albany Molecular Research Inc., Buffalo, New York, USA
| | - Grant Carr
- Discovery Biology, Albany Molecular Research Inc., Buffalo, New York, USA
| | - Guangyu Zhu
- Discovery Biology, Albany Molecular Research Inc., Buffalo, New York, USA
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17
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Anne Esguerra Z, Watanabe G, Okitsu CY, Hsieh CL, Lieber MR. DNA-PKcs chemical inhibition versus genetic mutation: Impact on the junctional repair steps of V(D)J recombination. Mol Immunol 2020; 120:93-100. [PMID: 32113132 DOI: 10.1016/j.molimm.2020.01.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 01/14/2020] [Accepted: 01/24/2020] [Indexed: 12/20/2022]
Abstract
Spontaneous DNA-PKcs deficiencies in animals result in a severe combined immunodeficiency (SCID) phenotype because DNA-PKcs is required to activate Artemis for V(D)J recombination coding end hairpin opening. The impact on signal joint formation in these spontaneous mutant mammals is variable. Genetically engineered DNA-PKcs null mice and cells from them show a >1,000-fold reduction in coding joint formation and minimal reduction in signal joint formation during V(D)J recombination. Does chemical inhibition of DNA-PKcs mimic this phenotype? M3814 (also known as Nedisertib) is a potent DNA-PKcs inhibitor. We find here that M3814 causes a quantitative reduction in coding joint formation relative to signal joint formation. The sequences of signal and coding junctions were within normal limits, though rare coding joints showed novel features. The signal junctions generally did not show evidence of resection into the signal ends that is often seen in cells that have genetic defects in DNA-PKcs. Comparison of the chemical inhibition findings here with the known results for spontaneous and engineered DNA-PKcs mutant mammals is informative for considering pharmacologic small molecule inhibition of DNA-PKcs in various types of neoplasia.
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Affiliation(s)
- Z Anne Esguerra
- USC Norris Comprehensive Cancer Ctr, Departments of Pathology, of Biochemistry & Molecular Biology, of Molecular Microbiology & Immunology, University of Southern California Keck School of Medicine, and the Molecular and Computational Biology Section of the Department of Biological Sciences, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA, 90089-9176, United States
| | - Go Watanabe
- USC Norris Comprehensive Cancer Ctr, Departments of Pathology, of Biochemistry & Molecular Biology, of Molecular Microbiology & Immunology, University of Southern California Keck School of Medicine, and the Molecular and Computational Biology Section of the Department of Biological Sciences, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA, 90089-9176, United States
| | - Cindy Y Okitsu
- Department of Urology, USC Norris Comprehensive Cancer Ctr, Los Angeles, CA, 90089 United States
| | - Chih-Lin Hsieh
- Department of Urology, USC Norris Comprehensive Cancer Ctr, Los Angeles, CA, 90089 United States
| | - Michael R Lieber
- USC Norris Comprehensive Cancer Ctr, Departments of Pathology, of Biochemistry & Molecular Biology, of Molecular Microbiology & Immunology, University of Southern California Keck School of Medicine, and the Molecular and Computational Biology Section of the Department of Biological Sciences, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA, 90089-9176, United States.
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18
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Pannunzio NR, Lieber MR. Constitutively active Artemis nuclease recognizes structures containing single-stranded DNA configurations. DNA Repair (Amst) 2019; 83:102676. [PMID: 31377101 DOI: 10.1016/j.dnarep.2019.102676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 07/24/2019] [Accepted: 07/25/2019] [Indexed: 01/03/2023]
Abstract
The Artemis nuclease recognizes and endonucleolytically cleaves at single-stranded to double-stranded DNA (ss/dsDNA) boundaries. It is also a key enzyme in the non-homologous end joining (NHEJ) DNA double-strand break repair pathway. Previously, a truncated form, Artemis-413, was developed that is constitutively active both in vitro and in vivo. Here, we use this constitutively active form of Artemis to detect DNA structures with ss/dsDNA boundaries that arise under topological stress. Topoisomerases prevent abnormal levels of torsional stress through modulation of positive and negative supercoiling. We show that overexpression of Artemis-413 in yeast cells carrying genetic mutations that ablate topoisomerase activity have an increased frequency of DNA double-strand breaks (DSBs). Based on the biochemical activity of Artemis, this suggests an increase in ss/dsDNA-containing structures upon increased torsional stress, with DSBs arising due to Artemis cutting at these ss/dsDNA structures. Camptothecin targets topoisomerase IB (Top1), and cells treated with camptothecin show increased DSBs. We find that expression of Artemis-413 in camptothecin-treated cells leads to a reduction in DSBs, the opposite of what we find with topoisomerase genetic mutations. This contrast between outcomes not only confirms that topoisomerase mutation and topoisomerase poisoning have distinct effects on cells, but also demonstrates the usefulness of Artemis-413 to study changes in DNA structure.
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Affiliation(s)
- Nicholas R Pannunzio
- Department of Pathology, Keck School of Medicine of University of Southern California, Los Angeles, CA, 90089, USA; Norris Comprehensive Cancer Center, Keck School of Medicine of University of Southern California, Los Angeles, CA, 90089, USA.
| | - Michael R Lieber
- Department of Pathology, Keck School of Medicine of University of Southern California, Los Angeles, CA, 90089, USA; Norris Comprehensive Cancer Center, Keck School of Medicine of University of Southern California, Los Angeles, CA, 90089, USA; Department of Biological Sciences, Molecular and Computational Biology Section, University of Southern California, Los Angeles, CA, 90089, USA.
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19
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Abstract
Evolutionarily, how RAG endonucleases in vertebrate immune systems could shed dangerous transposon-like propensities, and instead, support the organized assembly of antigen receptor variable domains, has been unclear. Recent structural work by Schatz and colleagues (Nature, 2019) identifies features of the RAG endonuclease deemed to be key in supporting this critical change in vertebrate advancement.
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Affiliation(s)
- Michael R Lieber
- University of Southern California, Los Angeles, CA 90089-9176, USA.
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20
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Loc'h J, Gerodimos CA, Rosario S, Tekpinar M, Lieber MR, Delarue M. Structural evidence for an in trans base selection mechanism involving Loop1 in polymerase μ at an NHEJ double-strand break junction. J Biol Chem 2019; 294:10579-10595. [PMID: 31138645 DOI: 10.1074/jbc.ra119.008739] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/13/2019] [Indexed: 11/06/2022] Open
Abstract
Eukaryotic DNA polymerase (Pol) X family members such as Pol μ and terminal deoxynucleotidyl transferase (TdT) are important components for the nonhomologous DNA end-joining (NHEJ) pathway. TdT participates in a specialized version of NHEJ, V(D)J recombination. It has primarily nontemplated polymerase activity but can take instructions across strands from the downstream dsDNA, and both activities are highly dependent on a structural element called Loop1. However, it is unclear whether Pol μ follows the same mechanism, because the structure of its Loop1 is disordered in available structures. Here, we used a chimeric TdT harboring Loop1 of Pol μ that recapitulated the functional properties of Pol μ in ligation experiments. We solved three crystal structures of this TdT chimera bound to several DNA substrates at 1.96-2.55 Å resolutions, including a full DNA double-strand break (DSB) synapsis. We then modeled the full Pol μ sequence in the context of one these complexes. The atomic structure of an NHEJ junction with a Pol X construct that mimics Pol μ in a reconstituted system explained the distinctive properties of Pol μ compared with TdT. The structure suggested a mechanism of base selection relying on Loop1 and taking instructions via the in trans templating base independently of the primer strand. We conclude that our atomic-level structural observations represent a paradigm shift for the mechanism of base selection in the Pol X family of DNA polymerases.
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Affiliation(s)
- Jérôme Loc'h
- From the Unité de Dynamique Structurale des Macromolécules, Institut Pasteur, UMR 3528 du CNRS, 25 Rue du Dr. Roux, 75015 Paris, France and
| | - Christina A Gerodimos
- the Departments of Pathology, Biochemistry and Molecular Biology, and Molecular Microbiology and Immunology and the Department of Biological Sciences, Section of Molecular and Computational Biology, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
| | - Sandrine Rosario
- From the Unité de Dynamique Structurale des Macromolécules, Institut Pasteur, UMR 3528 du CNRS, 25 Rue du Dr. Roux, 75015 Paris, France and
| | - Mustafa Tekpinar
- From the Unité de Dynamique Structurale des Macromolécules, Institut Pasteur, UMR 3528 du CNRS, 25 Rue du Dr. Roux, 75015 Paris, France and
| | - Michael R Lieber
- the Departments of Pathology, Biochemistry and Molecular Biology, and Molecular Microbiology and Immunology and the Department of Biological Sciences, Section of Molecular and Computational Biology, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
| | - Marc Delarue
- From the Unité de Dynamique Structurale des Macromolécules, Institut Pasteur, UMR 3528 du CNRS, 25 Rue du Dr. Roux, 75015 Paris, France and
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21
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Duncan JR, Lieber MR, Adachi N, Wahl RL. Reply: Radiation Dose Does Matter: Mechanistic Insights into DNA Damage and Repair Support the Linear No-Threshold Model of Low-Dose Radiation Health Risks. J Nucl Med 2019; 60:437-438. [DOI: 10.2967/jnumed.118.223461] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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22
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23
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Duncan JR, Lieber MR, Adachi N, Wahl RL. Reply: Radiation Dose Does Matter: Mechanistic Insights into DNA Damage and Repair Support the Linear No-Threshold Model of Low-Dose Radiation Health Risks. J Nucl Med 2018; 59:1780-1781. [DOI: 10.2967/jnumed.118.218321] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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24
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Conlin MP, Reid DA, Small GW, Chang HH, Watanabe G, Lieber MR, Ramsden DA, Rothenberg E. DNA Ligase IV Guides End-Processing Choice during Nonhomologous End Joining. Cell Rep 2018; 20:2810-2819. [PMID: 28930678 DOI: 10.1016/j.celrep.2017.08.091] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 08/22/2017] [Accepted: 08/25/2017] [Indexed: 12/15/2022] Open
Abstract
Nonhomologous end joining (NHEJ) must adapt to diverse end structures during repair of chromosome breaks. Here, we investigate the mechanistic basis for this flexibility. DNA ends are aligned in a paired-end complex (PEC) by Ku, XLF, XRCC4, and DNA ligase IV (LIG4); we show by single-molecule analysis how terminal mispairs lead to mobilization of ends within PECs and consequent sampling of more end-alignment configurations. This remodeling is essential for direct ligation of damaged and mispaired ends during cellular NHEJ, since remodeling and ligation of such ends both require a LIG4-specific structural motif, insert1. Insert1 is also required for PEC remodeling that enables nucleolytic processing when end structures block direct ligation. Accordingly, cells expressing LIG4 lacking insert1 are sensitive to ionizing radiation. Cellular NHEJ of diverse ends thus identifies the steps necessary for repair through LIG4-mediated sensing of differences in end structure and consequent dynamic remodeling of aligned ends.
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Affiliation(s)
- Michael P Conlin
- Lineberger Comprehensive Cancer Center, Curriculum in Genetics and Molecular Biology, and Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Dylan A Reid
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA
| | - George W Small
- Lineberger Comprehensive Cancer Center, Curriculum in Genetics and Molecular Biology, and Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Howard H Chang
- University of Southern California Keck School of Medicine, Norris Comprehensive Cancer Center, Los Angeles, CA 90033, USA
| | - Go Watanabe
- University of Southern California Keck School of Medicine, Norris Comprehensive Cancer Center, Los Angeles, CA 90033, USA
| | - Michael R Lieber
- University of Southern California Keck School of Medicine, Norris Comprehensive Cancer Center, Los Angeles, CA 90033, USA
| | - Dale A Ramsden
- Lineberger Comprehensive Cancer Center, Curriculum in Genetics and Molecular Biology, and Department of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, NC 27599, USA.
| | - Eli Rothenberg
- Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY 10016, USA.
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25
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Duncan JR, Lieber MR, Adachi N, Wahl RL. Radiation Dose Does Matter: Mechanistic Insights into DNA Damage and Repair Support the Linear No-Threshold Model of Low-Dose Radiation Health Risks. J Nucl Med 2018; 59:1014-1016. [PMID: 29853652 DOI: 10.2967/jnumed.118.210252] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 05/21/2018] [Indexed: 11/16/2022] Open
Affiliation(s)
- James R Duncan
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri
| | - Michael R Lieber
- USC Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California; and
| | | | - Richard L Wahl
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri
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Pannunzio NR, Lieber MR. Concept of DNA Lesion Longevity and Chromosomal Translocations. Trends Biochem Sci 2018; 43:490-498. [PMID: 29735400 DOI: 10.1016/j.tibs.2018.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Revised: 04/07/2018] [Accepted: 04/08/2018] [Indexed: 01/11/2023]
Abstract
A subset of chromosomal translocations related to B cell malignancy in human patients arises due to DNA breaks occurring within defined 20-600 base pair (bp) zones. Several factors influence the breakage rate at these sites including transcription, DNA sequence, and topological tension. These factors favor non-B DNA structures that permit formation of transient single-stranded DNA (ssDNA), making the DNA more vulnerable to agents such as the enzyme activation-induced cytidine deaminase (AID) and reactive oxygen species (ROS). Certain DNA lesions created during the ssDNA state persist after the DNA resumes its normal duplex structure. We propose that factors favoring both formation of transient ssDNA and persistent DNA lesions are key in determining the DNA breakage mechanism.
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Affiliation(s)
- Nicholas R Pannunzio
- University of Southern California Keck School of Medicine, Norris Comprehensive Cancer Center, Los Angeles, CA 90033, USA
| | - Michael R Lieber
- University of Southern California Keck School of Medicine, Norris Comprehensive Cancer Center, Los Angeles, CA 90033, USA; Department of Pathology, Keck School of Medicine of USC, Los Angeles, CA 90033, USA; Department of Molecular Microbiology and Immunology, Keck School of Medicine of USC, Los Angeles, CA 90033, USA; Department of Biochemistry and Molecular Biology, Keck School of Medicine of USC, Los Angeles, CA 90033, USA; Section of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089, USA.
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Pannunzio NR, Lieber MR. AID and Reactive Oxygen Species Can Induce DNA Breaks within Human Chromosomal Translocation Fragile Zones. Mol Cell 2017; 68:901-912.e3. [PMID: 29220655 DOI: 10.1016/j.molcel.2017.11.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 10/02/2017] [Accepted: 11/10/2017] [Indexed: 01/07/2023]
Abstract
DNA double-strand breaks (DSBs) occurring within fragile zones of less than 200 base pairs account for the formation of the most common human chromosomal translocations in lymphoid malignancies, yet the mechanism of how breaks occur remains unknown. Here, we have transferred human fragile zones into S. cerevisiae in the context of a genetic assay to understand the mechanism leading to DSBs at these sites. Our findings indicate that a combination of factors is required to sensitize these regions. Foremost, DNA strand separation by transcription or increased torsional stress can expose these DNA regions to damage from either the expression of human AID or increased oxidative stress. This damage causes DNA lesions that, if not repaired quickly, are prone to nuclease cleavage, resulting in DSBs. Our results provide mechanistic insight into why human neoplastic translocation fragile DNA sequences are more prone to enzymes or agents that cause longer-lived DNA lesions.
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Affiliation(s)
- Nicholas R Pannunzio
- USC Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1441 Eastlake Avenue, Rm. 5428, Los Angeles, CA 90089, USA
| | - Michael R Lieber
- USC Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, 1441 Eastlake Avenue, Rm. 5428, Los Angeles, CA 90089, USA.
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Abstract
Nonhomologous DNA end-joining (NHEJ) is the predominant double-strand break (DSB) repair pathway throughout the cell cycle and accounts for nearly all DSB repair outside of the S and G2 phases. NHEJ relies on Ku to thread onto DNA termini and thereby improve the affinity of the NHEJ enzymatic components consisting of polymerases (Pol μ and Pol λ), a nuclease (the Artemis·DNA-PKcs complex), and a ligase (XLF·XRCC4·Lig4 complex). Each of the enzymatic components is distinctive for its versatility in acting on diverse incompatible DNA end configurations coupled with a flexibility in loading order, resulting in many possible junctional outcomes from one DSB. DNA ends can either be directly ligated or, if the ends are incompatible, processed until a ligatable configuration is achieved that is often stabilized by up to 4 bp of terminal microhomology. Processing of DNA ends results in nucleotide loss or addition, explaining why DSBs repaired by NHEJ are rarely restored to their original DNA sequence. Thus, NHEJ is a single pathway with multiple enzymes at its disposal to repair DSBs, resulting in a diversity of repair outcomes.
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Affiliation(s)
- Nicholas R Pannunzio
- From the Departments of Pathology, Biochemistry and Molecular Biology, and Molecular Microbiology and Immunology, Section of Molecular and Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
| | - Go Watanabe
- From the Departments of Pathology, Biochemistry and Molecular Biology, and Molecular Microbiology and Immunology, Section of Molecular and Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
| | - Michael R Lieber
- From the Departments of Pathology, Biochemistry and Molecular Biology, and Molecular Microbiology and Immunology, Section of Molecular and Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
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Reid DA, Conlin MP, Yin Y, Chang HH, Watanabe G, Lieber MR, Ramsden DA, Rothenberg E. Bridging of double-stranded breaks by the nonhomologous end-joining ligation complex is modulated by DNA end chemistry. Nucleic Acids Res 2017; 45:1872-1878. [PMID: 27924007 PMCID: PMC5389564 DOI: 10.1093/nar/gkw1221] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 11/22/2016] [Indexed: 01/02/2023] Open
Abstract
The nonhomologous end-joining (NHEJ) pathway is the primary repair pathway for DNA double strand breaks (DSBs) in humans. Repair is mediated by a core complex of NHEJ factors that includes a ligase (DNA Ligase IV; L4) that relies on juxtaposition of 3΄ hydroxyl and 5΄ phosphate termini of the strand breaks for catalysis. However, chromosome breaks arising from biological sources often have different end chemistries, and how these different end chemistries impact the way in which the core complex directs the necessary transitions from end pairing to ligation is not known. Here, using single-molecule FRET (smFRET), we show that prior to ligation, differences in end chemistry strongly modulate the bridging of broken ends by the NHEJ core complex. In particular, the 5΄ phosphate group is a recognition element for L4 and is critical for the ability of NHEJ factors to promote stable pairing of ends. Moreover, other chemical incompatibilities, including products of aborted ligation, are sufficient to disrupt end pairing. Based on these observations, we propose a mechanism for iterative repair of DSBs by NHEJ.
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Affiliation(s)
- Dylan A Reid
- New York University School of Medicine, Department of Biochemistry and Molecular Pharmacology, New York, NY 10016, USA
| | - Michael P Conlin
- University of North Carolina School of Medicine, Curriculum in Genetics and Molecular Biology and Department of Biochemistry and Biophysics, Chapel Hill, NC 27599, USA
| | - Yandong Yin
- New York University School of Medicine, Department of Biochemistry and Molecular Pharmacology, New York, NY 10016, USA
| | - Howard H Chang
- University of Southern California Keck School of Medicine, Norris Comprehensive Cancer Center, Los Angeles, CA 90033, USA
| | - Go Watanabe
- University of Southern California Keck School of Medicine, Norris Comprehensive Cancer Center, Los Angeles, CA 90033, USA
| | - Michael R Lieber
- University of Southern California Keck School of Medicine, Norris Comprehensive Cancer Center, Los Angeles, CA 90033, USA
| | - Dale A Ramsden
- University of North Carolina School of Medicine, Curriculum in Genetics and Molecular Biology and Department of Biochemistry and Biophysics, Chapel Hill, NC 27599, USA
| | - Eli Rothenberg
- New York University School of Medicine, Department of Biochemistry and Molecular Pharmacology, New York, NY 10016, USA
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Gerodimos CA, Chang HHY, Watanabe G, Lieber MR. Effects of DNA end configuration on XRCC4-DNA ligase IV and its stimulation of Artemis activity. J Biol Chem 2017; 292:13914-13924. [PMID: 28696258 DOI: 10.1074/jbc.m117.798850] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 07/05/2017] [Indexed: 11/06/2022] Open
Abstract
In humans, nonhomologous DNA end-joining (NHEJ) is the major pathway by which DNA double-strand breaks are repaired. Recognition of each broken DNA end by the DNA repair protein Ku is the first step in NHEJ, followed by the iterative binding of nucleases, DNA polymerases, and the XRCC4-DNA ligase IV (X4-LIV) complex in an order influenced by the configuration of the two DNA ends at the break site. The endonuclease Artemis improves joining efficiency by functioning in a complex with DNA-dependent protein kinase, catalytic subunit (DNA-PKcs) that carries out endonucleolytic cleavage of 5' and 3' overhangs. Previously, we observed that X4-LIV alone can stimulate Artemis activity on 3' overhangs, but this DNA-PKcs-independent endonuclease activity of Artemis awaited confirmation. Here, using in vitro nuclease and ligation assays, we find that stimulation of Artemis nuclease activity by X4-LIV and the efficiency of blunt-end ligation are determined by structural configurations at the DNA end. Specifically, X4-LIV stimulated Artemis to cut near the end of 3' overhangs without the involvement of other NHEJ proteins. Of note, this ligase complex is not able to stimulate Artemis activity at hairpins or at 5' overhangs. We also found that X4-LIV and DNA-PKcs interfere with one another with respect to stimulating Artemis activity at 3' overhangs, favoring the view that these NHEJ proteins are sequentially rather than concurrently recruited to DNA ends. These data suggest specific functional and positional relationships among these components that explain genetic and molecular features of NHEJ and V(D)J recombination within cells.
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Affiliation(s)
- Christina A Gerodimos
- From the Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology and the Department of Biological Sciences, Section of Molecular & Computational Biology, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
| | - Howard H Y Chang
- From the Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology and the Department of Biological Sciences, Section of Molecular & Computational Biology, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
| | - Go Watanabe
- From the Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology and the Department of Biological Sciences, Section of Molecular & Computational Biology, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033
| | - Michael R Lieber
- From the Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology and the Department of Biological Sciences, Section of Molecular & Computational Biology, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, California 90033.
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Rand KA, Song C, Dean E, Serie DJ, Curtin K, Sheng X, Hu D, Huff CA, Bernal-Mizrachi L, Tomasson MH, Ailawadhi S, Singhal S, Pawlish K, Peters ES, Bock CH, Stram A, Van Den Berg DJ, Edlund CK, Conti DV, Zimmerman T, Hwang AE, Huntsman S, Graff J, Nooka A, Kong Y, Pregja SL, Berndt SI, Blot WJ, Carpten J, Casey G, Chu L, Diver WR, Stevens VL, Lieber MR, Goodman PJ, Hennis AJM, Hsing AW, Mehta J, Kittles RA, Kolb S, Klein EA, Leske C, Murphy AB, Nemesure B, Neslund-Dudas C, Strom SS, Vij R, Rybicki BA, Stanford JL, Signorello LB, Witte JS, Ambrosone CB, Bhatti P, John EM, Bernstein L, Zheng W, Olshan AF, Hu JJ, Ziegler RG, Nyante SJ, Bandera EV, Birmann BM, Ingles SA, Press MF, Atanackovic D, Glenn MJ, Cannon-Albright LA, Jones B, Tricot G, Martin TG, Kumar SK, Wolf JL, Deming Halverson SL, Rothman N, Brooks-Wilson AR, Rajkumar SV, Kolonel LN, Chanock SJ, Slager SL, Severson RK, Janakiraman N, Terebelo HR, Brown EE, De Roos AJ, Mohrbacher AF, Colditz GA, Giles GG, Spinelli JJ, Chiu BC, Munshi NC, Anderson KC, Levy J, Zonder JA, Orlowski RZ, Lonial S, Camp NJ, Vachon CM, Ziv E, Stram DO, Hazelett DJ, Haiman CA, Cozen W. A Meta-analysis of Multiple Myeloma Risk Regions in African and European Ancestry Populations Identifies Putatively Functional Loci. Cancer Epidemiol Biomarkers Prev 2016; 25:1609-1618. [PMID: 27587788 PMCID: PMC5524541 DOI: 10.1158/1055-9965.epi-15-1193] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 06/20/2016] [Accepted: 07/05/2016] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Genome-wide association studies (GWAS) in European populations have identified genetic risk variants associated with multiple myeloma. METHODS We performed association testing of common variation in eight regions in 1,318 patients with multiple myeloma and 1,480 controls of European ancestry and 1,305 patients with multiple myeloma and 7,078 controls of African ancestry and conducted a meta-analysis to localize the signals, with epigenetic annotation used to predict functionality. RESULTS We found that variants in 7p15.3, 17p11.2, 22q13.1 were statistically significantly (P < 0.05) associated with multiple myeloma risk in persons of African ancestry and persons of European ancestry, and the variant in 3p22.1 was associated in European ancestry only. In a combined African ancestry-European ancestry meta-analysis, variation in five regions (2p23.3, 3p22.1, 7p15.3, 17p11.2, 22q13.1) was statistically significantly associated with multiple myeloma risk. In 3p22.1, the correlated variants clustered within the gene body of ULK4 Correlated variants in 7p15.3 clustered around an enhancer at the 3' end of the CDCA7L transcription termination site. A missense variant at 17p11.2 (rs34562254, Pro251Leu, OR, 1.32; P = 2.93 × 10-7) in TNFRSF13B encodes a lymphocyte-specific protein in the TNF receptor family that interacts with the NF-κB pathway. SNPs correlated with the index signal in 22q13.1 cluster around the promoter and enhancer regions of CBX7 CONCLUSIONS: We found that reported multiple myeloma susceptibility regions contain risk variants important across populations, supporting the use of multiple racial/ethnic groups with different underlying genetic architecture to enhance the localization and identification of putatively functional alleles. IMPACT A subset of reported risk loci for multiple myeloma has consistent effects across populations and is likely to be functional. Cancer Epidemiol Biomarkers Prev; 25(12); 1609-18. ©2016 AACR.
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Affiliation(s)
- Kristin A Rand
- Keck School of Medicine of USC and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California
| | - Chi Song
- Keck School of Medicine of USC and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California
| | | | | | - Karen Curtin
- University of Utah School of Medicine, Salt Lake City, Utah
| | - Xin Sheng
- Keck School of Medicine of USC and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California
| | - Donglei Hu
- University of California at San Francisco, San Francisco, California
| | - Carol Ann Huff
- Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, Maryland
| | | | - Michael H Tomasson
- Alvin J. Siteman Cancer Center, Washington University School of Medicine, Washington University, St. Louis, Missouri
| | | | - Seema Singhal
- Robert H. Lurie Cancer Center, Northwestern University, Chicago, Illinois
| | - Karen Pawlish
- New Jersey State Cancer Registry, New Jersey Department of Health, Trenton, New Jersey
| | - Edward S Peters
- Louisiana State University School of Public Health, Louisiana State University, New Orleans, Louisiana
| | - Cathryn H Bock
- Karmanos Cancer Institute and Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan
| | - Alex Stram
- Genomic Health, Inc., Redwood City, California
| | - David J Van Den Berg
- Keck School of Medicine of USC and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California
| | - Christopher K Edlund
- Keck School of Medicine of USC and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California
| | - David V Conti
- Keck School of Medicine of USC and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California
| | | | - Amie E Hwang
- Keck School of Medicine of USC and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California
| | - Scott Huntsman
- University of California at San Francisco, San Francisco, California
| | - John Graff
- Rutgers-Robert Wood Johnson Medical School, Rutgers State University of New Jersey, New Brunswick, New Jersey
| | - Ajay Nooka
- Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Yinfei Kong
- Keck School of Medicine of USC and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California
| | - Silvana L Pregja
- Karmanos Cancer Institute and Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan
| | - Sonja I Berndt
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, U.S. NIH, Bethesda, Maryland
| | - William J Blot
- International Epidemiology Institute, Rockville, Maryland
- Division of Epidemiology, Vanderbilt Epidemiology Center, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - John Carpten
- The Translational Genomics Research Institute, Phoenix, Arizona
| | - Graham Casey
- Keck School of Medicine of USC and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California
| | - Lisa Chu
- Cancer Prevention Institute of California, Fremont, California
- Stanford University School of Medicine and Stanford Cancer Institute, Palo Alto, California
| | | | | | - Michael R Lieber
- Keck School of Medicine of USC and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California
| | | | - Anselm J M Hennis
- Stony Brook University, Stony Brook, New York
- Chronic Disease Research Centre and Faculty of Medical Sciences, University of the West Indies, Bridgetown, Barbados
| | - Ann W Hsing
- Stanford University School of Medicine and Stanford Cancer Institute, Palo Alto, California
| | - Jayesh Mehta
- Robert H. Lurie Cancer Center, Northwestern University, Chicago, Illinois
| | - Rick A Kittles
- Department of Surgery, University of Arizona, Tucson, Arizona
| | - Suzanne Kolb
- Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Eric A Klein
- Glickman Urologic and Kidney Institute, Cleveland Clinic, Cleveland, Ohio
| | | | - Adam B Murphy
- Robert H. Lurie Cancer Center, Northwestern University, Chicago, Illinois
| | | | | | - Sara S Strom
- The University of Texas MD Anderson Cancer Center, University of Texas, Houston, Texas
| | - Ravi Vij
- Alvin J. Siteman Cancer Center, Washington University School of Medicine, Washington University, St. Louis, Missouri
| | | | - Janet L Stanford
- Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Lisa B Signorello
- Harvard School of Public Health, Harvard University, Boston, Massachusetts
| | - John S Witte
- Institute for Human Genetics, University of California, San Francisco, San Francisco, California
| | | | - Parveen Bhatti
- Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - Esther M John
- Cancer Prevention Institute of California, Fremont, California
- Stanford University School of Medicine and Stanford Cancer Institute, Palo Alto, California
| | - Leslie Bernstein
- Division of Cancer Etiology, Department of Population Sciences, Beckman Research Institute of the City of Hope, Duarte, California
| | - Wei Zheng
- International Epidemiology Institute, Rockville, Maryland
| | - Andrew F Olshan
- Gillings School of Global Public Health, and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina
| | - Jennifer J Hu
- Sylvester Comprehensive Cancer Center and Department of Epidemiology and Public Health, University of Miami Miller School of Medicine, Miami, Florida
| | - Regina G Ziegler
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, U.S. NIH, Bethesda, Maryland
| | - Sarah J Nyante
- Gillings School of Global Public Health, and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina
| | - Elisa V Bandera
- Rutgers-Robert Wood Johnson Medical School, Rutgers State University of New Jersey, New Brunswick, New Jersey
| | - Brenda M Birmann
- Harvard School of Public Health, Harvard University, Boston, Massachusetts
| | - Sue A Ingles
- Keck School of Medicine of USC and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California
| | - Michael F Press
- Keck School of Medicine of USC and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California
| | | | - Martha J Glenn
- University of Utah School of Medicine, Salt Lake City, Utah
| | | | - Brandt Jones
- University of Utah School of Medicine, Salt Lake City, Utah
| | | | - Thomas G Martin
- University of California at San Francisco, San Francisco, California
| | | | - Jeffrey L Wolf
- University of California at San Francisco, San Francisco, California
| | | | - Nathaniel Rothman
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, U.S. NIH, Bethesda, Maryland
| | | | | | - Laurence N Kolonel
- University of Hawaii Cancer Center, University of Hawaii, Honolulu, Hawaii
| | - Stephen J Chanock
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, U.S. NIH, Bethesda, Maryland
| | | | - Richard K Severson
- Karmanos Cancer Institute and Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan
| | | | | | | | | | - Ann F Mohrbacher
- Keck School of Medicine of USC and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California
| | - Graham A Colditz
- Alvin J. Siteman Cancer Center, Washington University School of Medicine, Washington University, St. Louis, Missouri
| | - Graham G Giles
- Cancer Epidemiology Centre, Cancer Council of Victoria, Melbourne, Victoria, Australia
- School of Population and Global Health, Centre for Epidemiology and Biostatistics, University of Melbourne, Melbourne, Victoria, Australia
- Monash University, Melbourne, Melbourne, Victoria, Australia
| | - John J Spinelli
- BC Cancer Agency, Vancouver, Canada
- School of Population and Public Health, University of British Columbia, Vancouver, Canada
| | | | - Nikhil C Munshi
- Dana Farber Cancer Institute, Harvard School of Medicine, Harvard University, Boston, Massachusetts
| | - Kenneth C Anderson
- Dana Farber Cancer Institute, Harvard School of Medicine, Harvard University, Boston, Massachusetts
| | - Joan Levy
- Multiple Myeloma Research Foundation, Norwalk, Connecticut
| | - Jeffrey A Zonder
- Karmanos Cancer Institute and Department of Oncology, Wayne State University School of Medicine, Detroit, Michigan
| | - Robert Z Orlowski
- The University of Texas MD Anderson Cancer Center, University of Texas, Houston, Texas
| | - Sagar Lonial
- Winship Cancer Institute, Emory University, Atlanta, Georgia
| | - Nicola J Camp
- University of Utah School of Medicine, Salt Lake City, Utah
| | | | - Elad Ziv
- University of California at San Francisco, San Francisco, California
| | - Daniel O Stram
- Keck School of Medicine of USC and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California
| | - Dennis J Hazelett
- Center for Bioinformatics and Computational Biology, Cedars Sinai Medical Center, Los Angeles, California.
| | - Christopher A Haiman
- Keck School of Medicine of USC and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California.
| | - Wendy Cozen
- Keck School of Medicine of USC and Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, California.
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Chang HHY, Watanabe G, Gerodimos CA, Ochi T, Blundell TL, Jackson SP, Lieber MR. Different DNA End Configurations Dictate Which NHEJ Components Are Most Important for Joining Efficiency. J Biol Chem 2016; 291:24377-24389. [PMID: 27703001 PMCID: PMC5114395 DOI: 10.1074/jbc.m116.752329] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 09/26/2016] [Indexed: 02/02/2023] Open
Abstract
The nonhomologous DNA end-joining (NHEJ) pathway is a key mechanism for repairing dsDNA breaks that occur often in eukaryotic cells. In the simplest model, these breaks are first recognized by Ku, which then interacts with other NHEJ proteins to improve their affinity at DNA ends. These include DNA-PKcs and Artemis for trimming the DNA ends; DNA polymerase μ and λ to add nucleotides; and the DNA ligase IV complex to ligate the ends with the additional factors, XRCC4 (X-ray repair cross-complementing protein 4), XLF (XRCC4-like factor/Cernunos), and PAXX (paralog of XRCC4 and XLF). In vivo studies have demonstrated the degrees of importance of these NHEJ proteins in the mechanism of repair of dsDNA breaks, but interpretations can be confounded by other cellular processes. In vitro studies with NHEJ proteins have been performed to evaluate the nucleolytic resection, polymerization, and ligation steps, but a complete system has been elusive. Here we have developed a NHEJ reconstitution system that includes the nuclease, polymerase, and ligase components to evaluate relative NHEJ efficiency and analyze ligated junctional sequences for various types of DNA ends, including blunt, 5' overhangs, and 3' overhangs. We find that different dsDNA end structures have differential dependence on these enzymatic components. The dependence of some end joining on only Ku and XRCC4·DNA ligase IV allows us to formulate a physical model that incorporates nuclease and polymerase components as needed.
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Affiliation(s)
- Howard H Y Chang
- From the Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology and the Section of Molecular & Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, 90033 and
| | - Go Watanabe
- From the Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology and the Section of Molecular & Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, 90033 and
| | - Christina A Gerodimos
- From the Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology and the Section of Molecular & Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, 90033 and
| | - Takashi Ochi
- the Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge CB2 1QN, United Kingdom
| | - Tom L Blundell
- the Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge CB2 1QN, United Kingdom
| | - Stephen P Jackson
- the Gurdon Institute and Department of Biochemistry, University of Cambridge, Cambridge CB2 1QN, United Kingdom
| | - Michael R Lieber
- From the Departments of Pathology, Biochemistry & Molecular Biology, and Molecular Microbiology & Immunology and the Section of Molecular & Computational Biology, Department of Biological Sciences, Norris Comprehensive Cancer Center, University of Southern California Keck School of Medicine, Los Angeles, CA, 90033 and.
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Abstract
Analysis of chromosomal translocation sequence locations in human lymphomas has provided valuable clues about the mechanism of the translocations and when they occur. Biochemical analyses on the mechanisms of DNA breakage and rejoining permit formulation of detailed models of the human chromosomal translocation process in lymphoid neoplasms. Most human lymphomas are derived from B cells in which a DNA break at an oncogene is initiated by activation-induced deaminase (AID). The partner locus in many cases is located at one of the antigen receptor loci, and this break is generated by the recombination activating gene (RAG) complex or by AID. After breakage, the joining process typically occurs by non-homologous DNA end-joining (NHEJ). Some of the insights into this mechanism also apply to translocations that occur in non-lymphoid neoplasms.
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Affiliation(s)
- Michael R Lieber
- USC Norris Comprehensive Cancer Center, Room 5428, University of Southern California Keck School of Medicine, 1441 Eastlake Avenue, MC9176, Los Angeles, California 90089-9176, USA
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Chang HHY, Lieber MR. Structure-Specific nuclease activities of Artemis and the Artemis: DNA-PKcs complex. Nucleic Acids Res 2016; 44:4991-7. [PMID: 27198222 PMCID: PMC4914130 DOI: 10.1093/nar/gkw456] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 05/06/2016] [Indexed: 12/23/2022] Open
Abstract
Artemis is a vertebrate nuclease with both endo- and exonuclease activities that acts on a wide range of nucleic acid substrates. It is the main nuclease in the non-homologous DNA end-joining pathway (NHEJ). Not only is Artemis important for the repair of DNA double-strand breaks (DSBs) in NHEJ, it is essential in opening the DNA hairpin intermediates that are formed during V(D)J recombination. Thus, humans with Artemis deficiencies do not have T- or B-lymphocytes and are diagnosed with severe combined immunodeficiency (SCID). While Artemis is the only vertebrate nuclease capable of opening DNA hairpins, it has also been found to act on other DNA substrates that share common structural features. Here, we discuss the key structural features that all Artemis DNA substrates have in common, thus providing a basis for understanding how this structure-specific nuclease recognizes its DNA targets.
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Affiliation(s)
- Howard H Y Chang
- University of Southern California Keck School of Medicine, Norris Comprehensive Cancer Center, Los Angeles, CA 90089, USA
| | - Michael R Lieber
- University of Southern California Keck School of Medicine, Norris Comprehensive Cancer Center, Los Angeles, CA 90089, USA
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Greco GE, Matsumoto Y, Brooks RC, Lu Z, Lieber MR, Tomkinson AE. SCR7 is neither a selective nor a potent inhibitor of human DNA ligase IV. DNA Repair (Amst) 2016; 43:18-23. [PMID: 27235626 DOI: 10.1016/j.dnarep.2016.04.004] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 04/06/2016] [Indexed: 11/15/2022]
Abstract
DNA ligases are attractive therapeutics because of their involvement in completing the repair of almost all types of DNA damage. A series of DNA ligase inhibitors with differing selectivity for the three human DNA ligases were identified using a structure-based approach with one of these inhibitors being used to inhibit abnormal DNA ligase IIIα-dependent repair of DNA double-strand breaks (DSB)s in breast cancer, neuroblastoma and leukemia cell lines. Raghavan and colleagues reported the characterization of a derivative of one of the previously identified DNA ligase inhibitors, which they called SCR7 (designated SCR7-R in our experiments using SCR7). SCR7 appeared to show increased selectivity for DNA ligase IV, inhibit the repair of DSBs by the DNA ligase IV-dependent non-homologous end-joining (NHEJ) pathway, reduce tumor growth, and increase the efficacy of DSB-inducing therapeutic modalities in mouse xenografts. In attempting to synthesize SCR7, we encountered problems with the synthesis procedures and discovered discrepancies in its reported structure. We determined the structure of a sample of SCR7 and a related compound, SCR7-G, that is the major product generated by the published synthesis procedure for SCR7. We also found that SCR7-G has the same structure as the compound (SCR7-X) available from a commercial vendor (XcessBio). The various SCR7 preparations had similar activity in DNA ligation assay assays, exhibiting greater activity against DNA ligases I and III than DNA ligase IV. Furthermore, SCR7-R failed to inhibit DNA ligase IV-dependent V(D)J recombination in a cell-based assay. Based on our results, we conclude that SCR7 and the SCR7 derivatives are neither selective nor potent inhibitors of DNA ligase IV.
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Affiliation(s)
- George E Greco
- Department of Chemistry, Goucher College, Baltimore, MD, United States
| | - Yoshihiro Matsumoto
- Departments of Internal Medicine and Molecular Genetics and Microbiology, and University of New Mexico Cancer Center, University of New Mexico, Albuquerque, NM 87131, United States
| | - Rhys C Brooks
- Departments of Internal Medicine and Molecular Genetics and Microbiology, and University of New Mexico Cancer Center, University of New Mexico, Albuquerque, NM 87131, United States
| | - Zhengfei Lu
- Departments of Pathology, Biochemistry and Molecular Biology, Biological Sciences, and Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, Norris Comprehensive Cancer Center, Los Angeles, CA, United States
| | - Michael R Lieber
- Departments of Pathology, Biochemistry and Molecular Biology, Biological Sciences, and Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, Norris Comprehensive Cancer Center, Los Angeles, CA, United States
| | - Alan E Tomkinson
- Departments of Internal Medicine and Molecular Genetics and Microbiology, and University of New Mexico Cancer Center, University of New Mexico, Albuquerque, NM 87131, United States.
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Pannunzio NR, Lieber MR. Dissecting the Roles of Divergent and Convergent Transcription in Chromosome Instability. Cell Rep 2016; 14:1025-1031. [PMID: 26804908 DOI: 10.1016/j.celrep.2015.12.098] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Revised: 11/29/2015] [Accepted: 12/21/2015] [Indexed: 11/29/2022] Open
Abstract
The interplay of transcription, topological tension, and chromosome breakage is a subject of intense interest, but, with so many facets to the problem, it is difficult to test. Here, we vary the orientation of promoters relative to one another in a yeast system that permits sensitive detection of chromosome breaks. Interestingly, convergent transcription that would direct RNA polymerases into one another does not increase chromosome breakage. In contrast, divergent transcription that would create underwound and potentially single-stranded DNA does cause a marked increase in chromosome breakage. Furthermore, we examine the role that topoisomerases are playing in preventing genome instability at these promoters and find that Top2 is required to prevent instability at converging promoters.
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Affiliation(s)
- Nicholas R Pannunzio
- USC Norris Comprehensive Center, University of Southern California Keck School of Medicine, 1441 Eastlake Avenue, Room 5428, Los Angeles, CA 90089, USA
| | - Michael R Lieber
- USC Norris Comprehensive Center, University of Southern California Keck School of Medicine, 1441 Eastlake Avenue, Room 5428, Los Angeles, CA 90089, USA.
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Chang HHY, Watanabe G, Lieber MR. Unifying the DNA end-processing roles of the artemis nuclease: Ku-dependent artemis resection at blunt DNA ends. J Biol Chem 2015; 290:24036-50. [PMID: 26276388 DOI: 10.1074/jbc.m115.680900] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Indexed: 11/06/2022] Open
Abstract
Artemis is a member of the metallo-β-lactamase protein family of nucleases. It is essential in vertebrates because, during V(D)J recombination, the RAG complex generates hairpins when it creates the double strand breaks at V, D, and J segments, and Artemis is required to open the hairpins so that they can be joined. Artemis is a diverse endo- and exonuclease, and creating a unified model for its wide range of nuclease properties has been challenging. Here we show that Artemis resects iteratively into blunt DNA ends with an efficiency that reflects the AT-richness of the DNA end. GC-rich ends are not cut by Artemis alone because of a requirement for DNA end breathing (and confirmed using fixed pseudo-Y structures). All DNA ends are cut when both the DNA-dependent protein kinase catalytic subunit and Ku accompany Artemis but not when Ku is omitted. These are the first biochemical data demonstrating a Ku dependence of Artemis action on DNA ends of any configuration. The action of Artemis at blunt DNA ends is slower than at overhangs, consistent with a requirement for a slow DNA end breathing step preceding the cut. The AT sequence dependence, the order of strand cutting, the length of the cuts, and the Ku-dependence of Artemis action at blunt ends can be reconciled with the other nucleolytic properties of both Artemis and Artemis·DNA-PKcs in a model incorporating DNA end breathing of blunt ends to form transient single to double strand boundaries that have structural similarities to hairpins and fixed 5' and 3' overhangs.
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Affiliation(s)
- Howard H Y Chang
- From the Departments of Pathology, Biochemistry and Molecular Biology, Biological Sciences, and Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, Norris Comprehensive Cancer Center, Los Angeles, California
| | - Go Watanabe
- From the Departments of Pathology, Biochemistry and Molecular Biology, Biological Sciences, and Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, Norris Comprehensive Cancer Center, Los Angeles, California
| | - Michael R Lieber
- From the Departments of Pathology, Biochemistry and Molecular Biology, Biological Sciences, and Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, Norris Comprehensive Cancer Center, Los Angeles, California
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Zhang ZZ, Pannunzio NR, Lu Z, Hsu E, Yu K, Lieber MR. The repetitive portion of the Xenopus IgH Mu switch region mediates orientation-dependent class switch recombination. Mol Immunol 2015; 67:524-31. [PMID: 26277278 DOI: 10.1016/j.molimm.2015.07.039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 07/29/2015] [Accepted: 07/30/2015] [Indexed: 11/26/2022]
Abstract
Vertebrates developed immunoglobulin heavy chain (IgH) class switch recombination (CSR) to express different IgH constant regions. Most double-strand breaks for Ig CSR occur within the repetitive portion of the switch regions located upstream of each set of constant domain exons for the Igγ, Igα or Igϵ heavy chain. Unlike mammalian switch regions, Xenopus switch regions do not have a high G-density on the non-template DNA strand. In previous studies, when Xenopus Sμ DNA was moved to the genome of mice, it is able to support substantial CSR when it is used to replace the murine Sγ1 region. Here, we tested both the 2kb repetitive portion and the 4.6 kb full-length portions of the Xenopus Sμ in both their natural (forward) orientation relative to the constant domain exons, as well as the opposite (reverse) orientation. Consistent with previous work, we find that the 4.6 kb full-length Sμ mediates similar levels of CSR in both the forward and reverse orientations. Whereas, the forward orientation of the 2kb portion can restore the majority of the CSR level of the 4.6 kb full-length Sμ, the reverse orientation poorly supports R-looping and no CSR. The forward orientation of the 2kb repetitive portion has more GG dinucleotides on the non-template strand than the reverse orientation. The correlation of R-loop formation with CSR efficiency, as demonstrated in the 2kb repetitive fragment of the Xenopus switch region, confirms a role played by R-looping in CSR that appears to be conserved through evolution.
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Affiliation(s)
- Zheng Z Zhang
- USC Norris Comprehensive Cancer Ctr. Molecular and Computational Biology Program, Department of Biological Sciences, Departments of Pathology, Biochemistry & Molecular Biology, Molecular Microbiology & Immunology, Urology, University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm, 5428, Los Angeles, CA 90089-9176, United States
| | - Nicholas R Pannunzio
- USC Norris Comprehensive Cancer Ctr. Molecular and Computational Biology Program, Department of Biological Sciences, Departments of Pathology, Biochemistry & Molecular Biology, Molecular Microbiology & Immunology, Urology, University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm, 5428, Los Angeles, CA 90089-9176, United States
| | - Zhengfei Lu
- USC Norris Comprehensive Cancer Ctr. Molecular and Computational Biology Program, Department of Biological Sciences, Departments of Pathology, Biochemistry & Molecular Biology, Molecular Microbiology & Immunology, Urology, University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm, 5428, Los Angeles, CA 90089-9176, United States
| | - Ellen Hsu
- Department of Physiology and Pharmacology, State University of New York Downstate Medical Center, New York, NY 11203, United States
| | - Kefei Yu
- Department of Microbiology and Molecular Genetics, Michigan State University, 5175 Biomedical Physical Sciences, East Lansing, MI 48824, United States
| | - Michael R Lieber
- USC Norris Comprehensive Cancer Ctr. Molecular and Computational Biology Program, Department of Biological Sciences, Departments of Pathology, Biochemistry & Molecular Biology, Molecular Microbiology & Immunology, Urology, University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm, 5428, Los Angeles, CA 90089-9176, United States
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Swaminathan S, Klemm L, Park E, Papaemmanuil E, Ford A, Kweon SM, Trageser D, Hasselfeld B, Henke N, Mooster J, Geng H, Schwarz K, Kogan SC, Casellas R, Schatz DG, Lieber MR, Greaves MF, Müschen M. Mechanisms of clonal evolution in childhood acute lymphoblastic leukemia. Nat Immunol 2015; 16:766-774. [PMID: 25985233 PMCID: PMC4475638 DOI: 10.1038/ni.3160] [Citation(s) in RCA: 139] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 03/26/2015] [Indexed: 12/14/2022]
Abstract
Childhood acute lymphoblastic leukemia (ALL) can often be traced to a pre-leukemic clone carrying a prenatal genetic lesion. Postnatally acquired mutations then drive clonal evolution toward overt leukemia. The enzymes RAG1-RAG2 and AID, which diversify immunoglobulin-encoding genes, are strictly segregated in developing cells during B lymphopoiesis and peripheral mature B cells, respectively. Here we identified small pre-BII cells as a natural subset with increased genetic vulnerability owing to concurrent activation of these enzymes. Consistent with epidemiological findings on childhood ALL etiology, susceptibility to genetic lesions during B lymphopoiesis at the transition from the large pre-BII cell stage to the small pre-BII cell stage was exacerbated by abnormal cytokine signaling and repetitive inflammatory stimuli. We demonstrated that AID and RAG1-RAG2 drove leukemic clonal evolution with repeated exposure to inflammatory stimuli, paralleling chronic infections in childhood.
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Affiliation(s)
- Srividya Swaminathan
- Department of Laboratory Medicine, University of California San Francisco, CA, 94143
| | - Lars Klemm
- Department of Laboratory Medicine, University of California San Francisco, CA, 94143
- University of Freiburg, Faculty of Biology, 79104 Freiburg, Germany
| | - Eugene Park
- Department of Laboratory Medicine, University of California San Francisco, CA, 94143
- Department of Haematology, University of Cambridge, Cambridge UK
| | | | - Anthony Ford
- Centre for Evolution and Cancer, The Institute of Cancer Research, London UK
| | - Soo-Mi Kweon
- University of Southern California, Los Angeles, CA
| | | | | | | | | | - Huimin Geng
- Department of Laboratory Medicine, University of California San Francisco, CA, 94143
| | - Klaus Schwarz
- Institute for Transfusion Medicine, University of Ulm, Ulm, Germany
| | - Scott C Kogan
- Department of Laboratory Medicine, University of California San Francisco, CA, 94143
| | | | | | | | - Mel F Greaves
- Centre for Evolution and Cancer, The Institute of Cancer Research, London UK
| | - Markus Müschen
- Department of Laboratory Medicine, University of California San Francisco, CA, 94143
- Department of Haematology, University of Cambridge, Cambridge UK
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Zhang ZZ, Hsieh CL, Okitsu CY, Han L, Yu K, Lieber MR. Effect of CpG dinucleotides within IgH switch region repeats on immunoglobulin class switch recombination. Mol Immunol 2015; 66:284-9. [PMID: 25899867 DOI: 10.1016/j.molimm.2015.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 03/31/2015] [Accepted: 04/04/2015] [Indexed: 12/30/2022]
Abstract
Immunoglobulin (Ig) heavy chains undergo class switch recombination (CSR) to change the heavy chain isotype from IgM to IgG, A or E. The switch regions are several kilobases long, repetitive, and G-rich on the nontemplate strand. They are also relatively depleted of CpG (also called CG) sites for unknown reasons. Here we use synthetic switch regions at the IgH switch alpha (Sα) locus to test the effect of CpG sites and to try to understand why the IgH switch sequences evolved to be relatively depleted of CpG. We find that even just two CpG sites within an 80 bp synthetic switch repeat iterated 15 times (total switch region length of 1200 bp containing 30 CpG sites) are sufficient to dramatically reduce both Ig CSR and transcription through the switch region from the upstream Iα sterile transcript promoter, which is the promoter that directs transcripts through the Sα region. De novo DNA methylation occurs at the four CpG sites in and around the Iα promoter when each 80 bp Iα switch repeat contains the two CpG sites. Thus, a relatively low density of CpG sites within the switch repeats can induce upstream CpG methylation at the IgH alpha locus, and cause a substantial decrease in transcription from the sterile transcript promoter. This effect is likely the reason that switch regions evolved to contain very few CpG sites. We discuss these findings as they relate to DNA methylation and to Ig CSR.
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Affiliation(s)
- Zheng Z Zhang
- USC Norris Comprehensive Cancer Center, Molecular and Computational Biology Program, Department of Biological Sciences; Departments of Pathology, Biochemistry and Molecular Biology, Molecular Microbiology and Immunology, Urology, University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA 90089-9176, United States
| | - Chih-Lin Hsieh
- USC Norris Comprehensive Cancer Center, Molecular and Computational Biology Program, Department of Biological Sciences; Departments of Pathology, Biochemistry and Molecular Biology, Molecular Microbiology and Immunology, Urology, University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA 90089-9176, United States
| | - Cindy Yen Okitsu
- USC Norris Comprehensive Cancer Center, Molecular and Computational Biology Program, Department of Biological Sciences; Departments of Pathology, Biochemistry and Molecular Biology, Molecular Microbiology and Immunology, Urology, University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA 90089-9176, United States
| | - Li Han
- Department of Microbiology and Molecular Genetics, Michigan State University, 5175 Biomedical Physical Sciences, East Lansing, MI 48824, United States
| | - Kefei Yu
- Department of Microbiology and Molecular Genetics, Michigan State University, 5175 Biomedical Physical Sciences, East Lansing, MI 48824, United States.
| | - Michael R Lieber
- USC Norris Comprehensive Cancer Center, Molecular and Computational Biology Program, Department of Biological Sciences; Departments of Pathology, Biochemistry and Molecular Biology, Molecular Microbiology and Immunology, Urology, University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA 90089-9176, United States.
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Zhang ZZ, Pannunzio NR, Hsieh CL, Yu K, Lieber MR. Complexities due to single-stranded RNA during antibody detection of genomic rna:dna hybrids. BMC Res Notes 2015; 8:127. [PMID: 25890199 PMCID: PMC4393563 DOI: 10.1186/s13104-015-1092-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 03/24/2015] [Indexed: 12/21/2022] Open
Abstract
Background Long genomic R-loops in eukaryotes were first described at the immunoglobulin heavy chain locus switch regions using bisulfite sequencing and functional studies. A mouse monoclonal antibody called S9.6 has been used for immunoprecipitation (IP) to identify R-loops, based on the assumption that it is specific for RNA:DNA over other nucleic acid duplexes. However, recent work has demonstrated that a variable domain of S9.6 binds AU-rich RNA:RNA duplexes with a KD that is only 5.6-fold weaker than for RNA:DNA duplexes. Most IP protocols do not pre-clear the genomic nucleic acid with RNase A to remove free RNA. Fold back of ssRNA can readily generate RNA:RNA duplexes that may bind the S9.6 antibody, and adventitious binding of RNA may also create short RNA:DNA regions. Here we investigate whether RNase A is needed to obtain reliable IP with S9.6. Findings As our test locus, we chose the most well-documented site for kilobase-long mammalian genomic R-loops, the immunoglobulin heavy chain locus (IgH) class switch regions. The R-loops at this locus can be induced by using cytokines to stimulate transcription from germline transcript promoters. We tested IP using S9.6 with and without various RNase treatments. The RNase treatments included RNase H to destroy the RNA in an RNA:DNA duplex and RNase A to destroy single-stranded (ss) RNA to prevent it from binding S9.6 directly (as duplex RNA) and to prevent the ssRNA from annealing to the genome, resulting in adventitious RNA:DNA hybrids. We find that optimal detection of RNA:DNA duplexes requires removal of ssRNA using RNase A. Without RNase A treatment, known regions of R-loop formation containing RNA:DNA duplexes can not be reliably detected. With RNase A treatment, a signal can be detected over background, but only within a limited 2 or 3-fold range, even with a stable kilobase-long genomic R-loop. Conclusion Any use of the S9.6 antibody must be preceded by RNase A treatment to remove free ssRNA that may compete for the S9.6 binding by forming RNA:RNA regions or short, transient RNA:DNA duplexes. Caution should be used when interpreting S9.6 data, and confirmation by independent structural and functional methods is essential. Electronic supplementary material The online version of this article (doi:10.1186/s13104-015-1092-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Zheng Z Zhang
- USC Norris Comprehensive Cancer Ctr. Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA, 90089-9176, USA. .,Departments of Pathology, Biochemistry & Molecular Biology; Molecular Microbiology & Immunology; Urology, University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA, 90089-9176, USA.
| | - Nicholas R Pannunzio
- USC Norris Comprehensive Cancer Ctr. Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA, 90089-9176, USA. .,Departments of Pathology, Biochemistry & Molecular Biology; Molecular Microbiology & Immunology; Urology, University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA, 90089-9176, USA.
| | - Chih-Lin Hsieh
- USC Norris Comprehensive Cancer Ctr. Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA, 90089-9176, USA. .,Departments of Pathology, Biochemistry & Molecular Biology; Molecular Microbiology & Immunology; Urology, University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA, 90089-9176, USA.
| | - Kefei Yu
- Department of Microbiology and Molecular Genetics, Michigan State University, 5175 Biomedical Physical Sciences, East Lansing, MI, 48824, USA.
| | - Michael R Lieber
- USC Norris Comprehensive Cancer Ctr. Molecular and Computational Biology Program, Department of Biological Sciences, University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA, 90089-9176, USA. .,Departments of Pathology, Biochemistry & Molecular Biology; Molecular Microbiology & Immunology; Urology, University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA, 90089-9176, USA.
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Lu Z, Lieber MR, Tsai AG, Pardo CE, Müschen M, Kladde MP, Hsieh CL. Human lymphoid translocation fragile zones are hypomethylated and have accessible chromatin. Mol Cell Biol 2015; 35:1209-22. [PMID: 25624348 PMCID: PMC4355534 DOI: 10.1128/mcb.01085-14] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Revised: 11/26/2014] [Accepted: 01/16/2015] [Indexed: 12/19/2022] Open
Abstract
Chromosomal translocations are a hallmark of hematopoietic malignancies. CG motifs within translocation fragile zones (typically 20 to 600 bp in size) are prone to chromosomal translocation in lymphomas. Here we demonstrate that the CG motifs in human translocation fragile zones are hypomethylated relative to the adjacent DNA. Using a methyltransferase footprinting assay on isolated nuclei (in vitro), we find that the chromatin at these fragile zones is accessible. We also examined in vivo accessibility using cellular expression of a prokaryotic methylase. Based on this assay, which measures accessibility over a much longer time interval than is possible with in vitro methods, these fragile zones were found to be more accessible than the adjacent DNA. Because DNA within the fragile zones can be methylated by both cellular and exogenous methyltransferases, the fragile zones are predominantly in a duplex DNA conformation. These observations permit more-refined models for why these zones are 100- to 1,000-fold more prone to undergo chromosomal translocation than the adjacent regions.
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Affiliation(s)
- Zhengfei Lu
- USC Norris Comprehensive Cancer Ctr., Los Angeles, California, USA
| | - Michael R Lieber
- USC Norris Comprehensive Cancer Ctr., Los Angeles, California, USA
| | - Albert G Tsai
- USC Norris Comprehensive Cancer Ctr., Los Angeles, California, USA
| | - Carolina E Pardo
- Department of Biochemistry & Molecular Biology, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Markus Müschen
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, California, USA
| | - Michael P Kladde
- Department of Biochemistry & Molecular Biology, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Chih-Lin Hsieh
- USC Norris Comprehensive Cancer Ctr., Los Angeles, California, USA
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Zhang ZZ, Pannunzio NR, Hsieh CL, Yu K, Lieber MR. The role of G-density in switch region repeats for immunoglobulin class switch recombination. Nucleic Acids Res 2014; 42:13186-93. [PMID: 25378327 PMCID: PMC4245955 DOI: 10.1093/nar/gku1100] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 10/19/2014] [Accepted: 10/22/2014] [Indexed: 02/06/2023] Open
Abstract
The boundaries of R-loops are well-documented at immunoglobulin heavy chain loci in mammalian B cells. Within primary B cells or B cell lines, the upstream boundaries of R-loops typically begin early in the repetitive portion of the switch regions. Most R-loops terminate within the switch repetitive zone, but the remainder can extend a few hundred base pairs further, where G-density on the non-template DNA strand gradually drops to the genome average. Whether the G-density determines how far the R-loops extend is an important question. We previously studied the role of G-clusters in initiating R-loop formation, but we did not examine the role of G-density in permitting the elongation of the R-loop, after it had initiated. Here, we vary the G-density of different portions of the switch region in a murine B cell line. We find that both class switch recombination (CSR) and R-loop formation decrease significantly when the overall G-density is reduced from 46% to 29%. Short 50 bp insertions with low G-density within switch regions do not appear to affect either CSR or R-loop elongation, whereas a longer (150 bp) insertion impairs both. These results demonstrate that G-density is an important determinant of the length over which mammalian genomic R-loops extend.
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Affiliation(s)
- Zheng Z Zhang
- USC Norris Comprehensive Cancer Center, Molecular and Computational Biology Program, Departments of Biological Sciences; Pathology, Biochemistry & Molecular Biology; Molecular Microbiology & Immunology; Urology; University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA 90089-9176, USA
| | - Nicholas R Pannunzio
- USC Norris Comprehensive Cancer Center, Molecular and Computational Biology Program, Departments of Biological Sciences; Pathology, Biochemistry & Molecular Biology; Molecular Microbiology & Immunology; Urology; University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA 90089-9176, USA
| | - Chih-Lin Hsieh
- USC Norris Comprehensive Cancer Center, Molecular and Computational Biology Program, Departments of Biological Sciences; Pathology, Biochemistry & Molecular Biology; Molecular Microbiology & Immunology; Urology; University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA 90089-9176, USA
| | - Kefei Yu
- Department of Microbiology and Molecular Genetics, Michigan State University, 5175 Biomedical Physical Sciences, East Lansing, MI 48824, USA
| | - Michael R Lieber
- USC Norris Comprehensive Cancer Center, Molecular and Computational Biology Program, Departments of Biological Sciences; Pathology, Biochemistry & Molecular Biology; Molecular Microbiology & Immunology; Urology; University of Southern California Keck School of Medicine, 1441 Eastlake Ave., Rm. 5428, Los Angeles, CA 90089-9176, USA
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46
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Abstract
V(D)J recombination is the process by which the diversity of antigen receptor genes is generated and is also indispensable for lymphocyte development. This recombination event occurs in a cell lineage- and stage-specific manner, and is carefully controlled by chromatin structure and ordered histone modifications. The recombinationally active V(D)J loci are associated with hypermethylation at lysine4 of histone H3 and hyperacetylation of histones H3/H4. The recombination activating gene 1 (RAG1) and RAG2 complex initiates recombination by introducing double-strand DNA breaks at recombination signal sequences (RSS) adjacent to each coding sequence. To be recognized by the RAG complex, RSS sites must be within an open chromatin context. In addition, the RAG complex specifically recognizes hypermethylated H3K4 through its plant homeodomain (PHD) finger in the RAG2 C terminus, which stimulates RAG catalytic activity via that interaction. In this review, we describe how histone methylation controls V(D)J recombination and discuss its potential role in lymphoid malignancy by mistargeting the RAG complex.
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Affiliation(s)
- Noriko Shimazaki
- Section of Molecular and Computational Biology, Departments of Pathology, Biochemistry and Molecular Biology, Molecular Microbiology and Immunology, USC Norris Comprehensive Cancer Ctr., Rm. 5428, 1441 Eastlake Ave., MC 9176, Los Angeles, CA, 90089-9176, USA,
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Zhang ZZ, Pannunzio NR, Han L, Hsieh CL, Yu K, Lieber MR. The strength of an Ig switch region is determined by its ability to drive R loop formation and its number of WGCW sites. Cell Rep 2014; 8:557-69. [PMID: 25017067 DOI: 10.1016/j.celrep.2014.06.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 05/20/2014] [Accepted: 06/12/2014] [Indexed: 12/22/2022] Open
Abstract
R loops exist at the murine IgH switch regions and possibly other locations, but their functional importance is unclear. In biochemical systems, R loop initiation requires DNA sequence regions containing clusters of G nucleotides, but cellular studies have not been done. Here, we vary the G-clustering, total switch region length, and the number of target sites (WGCW sites for the activation-induced deaminase) at synthetic switch regions in a murine B cell line to determine the effect on class switch recombination (CSR). G-clusters increase CSR regardless of their immediate proximity to the WGCW sites. This increase is accompanied by an increase in R loop formation. CSR efficiency correlates better with the absolute number of WGCW sites in the switch region rather than the total switch region length or density of WGCW sites. Thus, the overall strength of the switch region depends on G-clusters, which initiate R loop formation, and on the number of WGCW sites.
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Affiliation(s)
- Zheng Z Zhang
- USC Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90033, USA; Molecular and Computational Biology Section, Department of Biological Sciences, USC Dornsife, University of Southern California, Los Angeles, CA 90033, USA; Departments of Pathology, Biochemistry & Molecular Biology, Molecular Microbiology & Immunology, and Urology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Nicholas R Pannunzio
- USC Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90033, USA; Molecular and Computational Biology Section, Department of Biological Sciences, USC Dornsife, University of Southern California, Los Angeles, CA 90033, USA; Departments of Pathology, Biochemistry & Molecular Biology, Molecular Microbiology & Immunology, and Urology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Li Han
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Chih-Lin Hsieh
- USC Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90033, USA; Molecular and Computational Biology Section, Department of Biological Sciences, USC Dornsife, University of Southern California, Los Angeles, CA 90033, USA; Departments of Pathology, Biochemistry & Molecular Biology, Molecular Microbiology & Immunology, and Urology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Kefei Yu
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA.
| | - Michael R Lieber
- USC Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, CA 90033, USA; Molecular and Computational Biology Section, Department of Biological Sciences, USC Dornsife, University of Southern California, Los Angeles, CA 90033, USA; Departments of Pathology, Biochemistry & Molecular Biology, Molecular Microbiology & Immunology, and Urology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA.
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Li S, Chang HH, Niewolik D, Hedrick MP, Pinkerton AB, Hassig CA, Schwarz K, Lieber MR. Evidence that the DNA endonuclease ARTEMIS also has intrinsic 5'-exonuclease activity. J Biol Chem 2014; 289:7825-34. [PMID: 24500713 DOI: 10.1074/jbc.m113.544874] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
ARTEMIS is a member of the metallo-β-lactamase protein family. ARTEMIS has endonuclease activity at DNA hairpins and at 5'- and 3'-DNA overhangs of duplex DNA, and this endonucleolytic activity is dependent upon DNA-PKcs. There has been uncertainty about whether ARTEMIS also has 5'-exonuclease activity on single-stranded DNA and 5'-overhangs, because this 5'-exonuclease is not dependent upon DNA-PKcs. Here, we show that the 5'-exonuclease and the endonuclease activities co-purify. Second, we show that a point mutant of ARTEMIS at a putative active site residue (H115A) markedly reduces both the endonuclease activity and the 5'-exonuclease activity. Third, divalent cation effects on the 5'-exonuclease and the endonuclease parallel one another. Fourth, both the endonuclease activity and 5'-exonuclease activity of ARTEMIS can be blocked in parallel by small molecule inhibitors, which do not block unrelated nucleases. We conclude that the 5'-exonuclease is intrinsic to ARTEMIS, making it relevant to the role of ARTEMIS in nonhomologous DNA end joining.
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Affiliation(s)
- Sicong Li
- From the Departments of Pathology, Biochemistry and Molecular Biology, Biological Sciences, and Molecular Microbiology and Immunology, University of Southern California Keck School of Medicine, Norris Comprehensive Cancer Center, Los Angeles, California 90089-9176
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Okitsu CY, Van Den Berg DJ, Lieber MR, Hsieh CL. Reproducibility and reliability of SNP analysis using human cellular DNA at or near nanogram levels. BMC Res Notes 2013; 6:515. [PMID: 24314330 PMCID: PMC4029319 DOI: 10.1186/1756-0500-6-515] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 12/02/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Illumina SNP arrays have been routinely used for genome-wide association studies to identify potential biomarkers for various diseases. The recommended 200 ng of DNA for high-quality results is a roadblock to utilizing this assay when such quantities of DNA are not available. The goal of this study is to determine the reproducibility and reliability of the assay when reduced amounts of DNA are used for the SNP arrays. FINDINGS A serial 3-fold reduction of DNA from 200 ng to 0.8 ng was used for an Illumina SNP array in duplicates (200 ng, 66.7 ng, 22,2 ng, and 7.4 ng) or triplicates (2.47 ng and 0.8 ng). The reproducibility of the assay was determined by comparing allele calls (genotypes) at each locus within the duplicates or triplicates. The reliability of samples of reduced quantity was determined by comparing allele calls from samples of different quantities. As expected, the reproducibility and reliability both decrease with decreasing amounts of DNA used for the arrays. However, results of comparable quality to the 200 ng DNA recommended by Illumina can be obtained with much reduced amounts of DNA. CONCLUSION Reasonably reproducible and reliable results can be obtained with quantities of DNA, as low as 0.8 ng (equivalent to 133 human cells), well below the manufacturer's recommendation. Results of nearly equal quality to that of using 200 ng DNA can be obtained with 22.2 ng of DNA reliably, and clearly acceptable data can be obtained using 7.4 ng of DNA for Illumina SNP arrays.
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Affiliation(s)
| | | | | | - Chih-Lin Hsieh
- Department of Urology, University of Southern California, 1441 Eastlake Ave,,Rm 5420, Los Angeles, CA 90033, USA.
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Hsieh JCF, Van Den Berg D, Kang H, Hsieh CL, Lieber MR. Large chromosome deletions, duplications, and gene conversion events accumulate with age in normal human colon crypts. Aging Cell 2013; 12:269-79. [PMID: 23425690 DOI: 10.1111/acel.12053] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/03/2013] [Indexed: 11/30/2022] Open
Abstract
Little is known about the types and numbers of mutations that may accumulate in normal human cells with age. Such information would require obtaining enough DNA from a single cell to accurately carry out reliable analysis despite extensive amplification; and complete genomic coverage under these circumstances is difficult. We have compared colon crypts, which are putatively clonal and contain ~2000 cells each, to determine how much somatic genetic variation occurs in vivo (without ex vivo cell culturing). Using high-density SNP microarrays, we find that chromosome deletions, duplications, and gene conversions were significantly more frequent in colons from the older individuals. These changes affected lengths ranging from 73 kb to 46 Mb. Although detection requires progeny of a single mutant stem cell to reach niche dominance over neighboring stem cells, none of the deletions appear likely to confer a selective advantage. Mutations can become fixed randomly during stem cell evolution through neutral drift in normal human crypts. The fact that chromosomal changes are detected in individual crypts with increasing age suggests that either such changes accumulate with age or single stem cell dominance increases with age, and the former is more likely. This progressive genome-wide divergence of human somatic cells with age has implications for aging and disease in multicellular organisms.
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Affiliation(s)
- John C. F. Hsieh
- USC Norris Comprehensive Cancer Center; University of Southern California Keck School of Medicine; 1441 Eastlake Ave., MC9176; Los Angeles; CA; 90089; USA
| | - David Van Den Berg
- USC Norris Comprehensive Cancer Center; University of Southern California Keck School of Medicine; 1441 Eastlake Ave., MC9176; Los Angeles; CA; 90089; USA
| | - Haeyoun Kang
- USC Norris Comprehensive Cancer Center; University of Southern California Keck School of Medicine; 1441 Eastlake Ave., MC9176; Los Angeles; CA; 90089; USA
| | - Chih-Lin Hsieh
- USC Norris Comprehensive Cancer Center; University of Southern California Keck School of Medicine; 1441 Eastlake Ave., MC9176; Los Angeles; CA; 90089; USA
| | - Michael R. Lieber
- USC Norris Comprehensive Cancer Center; University of Southern California Keck School of Medicine; 1441 Eastlake Ave., MC9176; Los Angeles; CA; 90089; USA
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