The structure-selective endonucleases GEN1 and MUS81 mediate complementary functions in safeguarding the genome of proliferating B lymphocytes

During the development of humoral immunity, activated B lymphocytes undergo vigorous proliferative, transcriptional, metabolic, and DNA remodeling activities; hence, their genomes are constantly exposed to an onslaught of genotoxic agents and processes. Branched DNA intermediates generated during re...

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Main Authors: Keith Conrad Fernandez, Laura Feeney, Ryan M Smolkin, Wei-Feng Yen, Allysia J Matthews, William Alread, John HJ Petrini, Jayanta Chaudhuri
Format: Article
Language:English
Published: eLife Sciences Publications Ltd 2022-10-01
Series:eLife
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Online Access:https://elifesciences.org/articles/77073
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author Keith Conrad Fernandez
Laura Feeney
Ryan M Smolkin
Wei-Feng Yen
Allysia J Matthews
William Alread
John HJ Petrini
Jayanta Chaudhuri
author_facet Keith Conrad Fernandez
Laura Feeney
Ryan M Smolkin
Wei-Feng Yen
Allysia J Matthews
William Alread
John HJ Petrini
Jayanta Chaudhuri
author_sort Keith Conrad Fernandez
collection DOAJ
description During the development of humoral immunity, activated B lymphocytes undergo vigorous proliferative, transcriptional, metabolic, and DNA remodeling activities; hence, their genomes are constantly exposed to an onslaught of genotoxic agents and processes. Branched DNA intermediates generated during replication and recombinational repair pose genomic threats if left unresolved, and so they must be eliminated by structure-selective endonucleases to preserve the integrity of these DNA transactions for the faithful duplication and propagation of genetic information. To investigate the role of two such enzymes, GEN1 and MUS81, in B cell biology, we established B-cell conditional knockout mouse models and found that deletion of GEN1 and MUS81 in early B-cell precursors abrogates the development and maturation of B-lineage cells while the loss of these enzymes in mature B cells inhibits the generation of robust germinal centers. Upon activation, these double-null mature B lymphocytes fail to proliferate and survive while exhibiting transcriptional signatures of p53 signaling, apoptosis, and type I interferon response. Metaphase spreads of these endonuclease-deficient cells show severe and diverse chromosomal abnormalities, including a preponderance of chromosome breaks, consistent with a defect in resolving recombination intermediates. These observations underscore the pivotal roles of GEN1 and MUS81 in safeguarding the genome to ensure the proper development and proliferation of B lymphocytes.
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spelling doaj-art-c5a7957245bf45f98cfc381bda670cc82025-08-20T14:54:04ZengeLife Sciences Publications LtdeLife2050-084X2022-10-011110.7554/eLife.77073The structure-selective endonucleases GEN1 and MUS81 mediate complementary functions in safeguarding the genome of proliferating B lymphocytesKeith Conrad Fernandez0https://orcid.org/0000-0003-3757-8271Laura Feeney1Ryan M Smolkin2Wei-Feng Yen3Allysia J Matthews4William Alread5John HJ Petrini6Jayanta Chaudhuri7https://orcid.org/0000-0002-3838-0075Immunology Program, Memorial Sloan Kettering Cancer Center, New York, United States; Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, United StatesMolecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, United StatesImmunology Program, Memorial Sloan Kettering Cancer Center, New York, United States; Gerstner Sloan Kettering Graduate School of Biomedical Sciences, New York, United StatesImmunology Program, Memorial Sloan Kettering Cancer Center, New York, United States; Biochemistry, Cellular and Molecular Biology Allied Program, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, United StatesImmunology Program, Memorial Sloan Kettering Cancer Center, New York, United States; Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, United StatesImmunology Program, Memorial Sloan Kettering Cancer Center, New York, United StatesMolecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, United States; Gerstner Sloan Kettering Graduate School of Biomedical Sciences, New York, United States; Biochemistry, Cellular and Molecular Biology Allied Program, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, United StatesImmunology Program, Memorial Sloan Kettering Cancer Center, New York, United States; Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Medical Sciences, Cornell University, New York, United States; Gerstner Sloan Kettering Graduate School of Biomedical Sciences, New York, United StatesDuring the development of humoral immunity, activated B lymphocytes undergo vigorous proliferative, transcriptional, metabolic, and DNA remodeling activities; hence, their genomes are constantly exposed to an onslaught of genotoxic agents and processes. Branched DNA intermediates generated during replication and recombinational repair pose genomic threats if left unresolved, and so they must be eliminated by structure-selective endonucleases to preserve the integrity of these DNA transactions for the faithful duplication and propagation of genetic information. To investigate the role of two such enzymes, GEN1 and MUS81, in B cell biology, we established B-cell conditional knockout mouse models and found that deletion of GEN1 and MUS81 in early B-cell precursors abrogates the development and maturation of B-lineage cells while the loss of these enzymes in mature B cells inhibits the generation of robust germinal centers. Upon activation, these double-null mature B lymphocytes fail to proliferate and survive while exhibiting transcriptional signatures of p53 signaling, apoptosis, and type I interferon response. Metaphase spreads of these endonuclease-deficient cells show severe and diverse chromosomal abnormalities, including a preponderance of chromosome breaks, consistent with a defect in resolving recombination intermediates. These observations underscore the pivotal roles of GEN1 and MUS81 in safeguarding the genome to ensure the proper development and proliferation of B lymphocytes.https://elifesciences.org/articles/77073B cell biologyDNA recombinationgenome stabilityholliday junctionstructure-selective endonucleases
spellingShingle Keith Conrad Fernandez
Laura Feeney
Ryan M Smolkin
Wei-Feng Yen
Allysia J Matthews
William Alread
John HJ Petrini
Jayanta Chaudhuri
The structure-selective endonucleases GEN1 and MUS81 mediate complementary functions in safeguarding the genome of proliferating B lymphocytes
eLife
B cell biology
DNA recombination
genome stability
holliday junction
structure-selective endonucleases
title The structure-selective endonucleases GEN1 and MUS81 mediate complementary functions in safeguarding the genome of proliferating B lymphocytes
title_full The structure-selective endonucleases GEN1 and MUS81 mediate complementary functions in safeguarding the genome of proliferating B lymphocytes
title_fullStr The structure-selective endonucleases GEN1 and MUS81 mediate complementary functions in safeguarding the genome of proliferating B lymphocytes
title_full_unstemmed The structure-selective endonucleases GEN1 and MUS81 mediate complementary functions in safeguarding the genome of proliferating B lymphocytes
title_short The structure-selective endonucleases GEN1 and MUS81 mediate complementary functions in safeguarding the genome of proliferating B lymphocytes
title_sort structure selective endonucleases gen1 and mus81 mediate complementary functions in safeguarding the genome of proliferating b lymphocytes
topic B cell biology
DNA recombination
genome stability
holliday junction
structure-selective endonucleases
url https://elifesciences.org/articles/77073
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