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Ago2 and a miRNA reduce Topoisomerase 1 for enhancing DNA cleavage in antibody diversification by activation-induced cytidine deaminase

Activation-induced cytidine deaminase (AID) is the essential enzyme for imprinting immunological memory through class switch recombination (CSR) and somatic hypermutation (SHM) of the immunoglobulin (Ig) gene. AID-dependent reduction of Topoisomerase 1 (Top1) promotes DNA cleavage that occurs upon I...

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Autores principales: Kobayashi, Maki, Wakaguri, Hiroyuki, Shimizu, Masakazu, Higasa, Koichiro, Matsuda, Fumihiko, Honjo, Tasuku
Formato: Online Artículo Texto
Lenguaje:English
Publicado: National Academy of Sciences 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10161001/
https://www.ncbi.nlm.nih.gov/pubmed/37094168
http://dx.doi.org/10.1073/pnas.2216918120
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author Kobayashi, Maki
Wakaguri, Hiroyuki
Shimizu, Masakazu
Higasa, Koichiro
Matsuda, Fumihiko
Honjo, Tasuku
author_facet Kobayashi, Maki
Wakaguri, Hiroyuki
Shimizu, Masakazu
Higasa, Koichiro
Matsuda, Fumihiko
Honjo, Tasuku
author_sort Kobayashi, Maki
collection PubMed
description Activation-induced cytidine deaminase (AID) is the essential enzyme for imprinting immunological memory through class switch recombination (CSR) and somatic hypermutation (SHM) of the immunoglobulin (Ig) gene. AID-dependent reduction of Topoisomerase 1 (Top1) promotes DNA cleavage that occurs upon Ig gene diversification, whereas the mechanism behind AID-induced Top1 reduction remains unclear. Here, we clarified the contribution of the microRNA-Ago2 complex in AID-dependent Top1 decrease. Ago2 binds to Top1 3′UTR with two regions of AID-dependent Ago2-binding sites (5′- and 3′dABs). Top1 3′UTR knockout (3′UTRKO) in B lymphoma cells leads to decreases in DNA break efficiency in the IgH gene accompanied by a reduction in CSR and SHM frequencies. Furthermore, AID-dependent Top1 protein reduction and Ago2-binding to Top1 mRNA are down-regulated in 3′UTRKO cells. Top1 mRNA in the highly translated fractions of the sucrose gradient is decreased in an AID-dependent and Top1 3′UTR–mediated manner, resulting in a decrease in Top1 protein synthesis. Both AID and Ago2 localize in the mRNA-binding protein fractions and they interact with each other. Furthermore, we found some candidate miRNAs which possibly bind to 5′- and 3′dAB in Top1 mRNA. Among them, miR-92a-3p knockdown induces the phenotypes of 3′UTRKO cells to wild-type cells whereas it does not impact on 3′UTRKO cells. Taken together, the Ago2-miR-92a-3p complex will be recruited to Top1 3′UTR in an AID-dependent manner and posttranscriptionally reduces Top1 protein synthesis. These consequences cause the increase in a non-B-DNA structure, enhance DNA cleavage by Top1 in the Ig gene and contribute to immunological memory formation.
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spelling pubmed-101610012023-10-24 Ago2 and a miRNA reduce Topoisomerase 1 for enhancing DNA cleavage in antibody diversification by activation-induced cytidine deaminase Kobayashi, Maki Wakaguri, Hiroyuki Shimizu, Masakazu Higasa, Koichiro Matsuda, Fumihiko Honjo, Tasuku Proc Natl Acad Sci U S A Biological Sciences Activation-induced cytidine deaminase (AID) is the essential enzyme for imprinting immunological memory through class switch recombination (CSR) and somatic hypermutation (SHM) of the immunoglobulin (Ig) gene. AID-dependent reduction of Topoisomerase 1 (Top1) promotes DNA cleavage that occurs upon Ig gene diversification, whereas the mechanism behind AID-induced Top1 reduction remains unclear. Here, we clarified the contribution of the microRNA-Ago2 complex in AID-dependent Top1 decrease. Ago2 binds to Top1 3′UTR with two regions of AID-dependent Ago2-binding sites (5′- and 3′dABs). Top1 3′UTR knockout (3′UTRKO) in B lymphoma cells leads to decreases in DNA break efficiency in the IgH gene accompanied by a reduction in CSR and SHM frequencies. Furthermore, AID-dependent Top1 protein reduction and Ago2-binding to Top1 mRNA are down-regulated in 3′UTRKO cells. Top1 mRNA in the highly translated fractions of the sucrose gradient is decreased in an AID-dependent and Top1 3′UTR–mediated manner, resulting in a decrease in Top1 protein synthesis. Both AID and Ago2 localize in the mRNA-binding protein fractions and they interact with each other. Furthermore, we found some candidate miRNAs which possibly bind to 5′- and 3′dAB in Top1 mRNA. Among them, miR-92a-3p knockdown induces the phenotypes of 3′UTRKO cells to wild-type cells whereas it does not impact on 3′UTRKO cells. Taken together, the Ago2-miR-92a-3p complex will be recruited to Top1 3′UTR in an AID-dependent manner and posttranscriptionally reduces Top1 protein synthesis. These consequences cause the increase in a non-B-DNA structure, enhance DNA cleavage by Top1 in the Ig gene and contribute to immunological memory formation. National Academy of Sciences 2023-04-24 2023-05-02 /pmc/articles/PMC10161001/ /pubmed/37094168 http://dx.doi.org/10.1073/pnas.2216918120 Text en Copyright © 2023 the Author(s). Published by PNAS. https://creativecommons.org/licenses/by-nc-nd/4.0/This article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND) (https://creativecommons.org/licenses/by-nc-nd/4.0/) .
spellingShingle Biological Sciences
Kobayashi, Maki
Wakaguri, Hiroyuki
Shimizu, Masakazu
Higasa, Koichiro
Matsuda, Fumihiko
Honjo, Tasuku
Ago2 and a miRNA reduce Topoisomerase 1 for enhancing DNA cleavage in antibody diversification by activation-induced cytidine deaminase
title Ago2 and a miRNA reduce Topoisomerase 1 for enhancing DNA cleavage in antibody diversification by activation-induced cytidine deaminase
title_full Ago2 and a miRNA reduce Topoisomerase 1 for enhancing DNA cleavage in antibody diversification by activation-induced cytidine deaminase
title_fullStr Ago2 and a miRNA reduce Topoisomerase 1 for enhancing DNA cleavage in antibody diversification by activation-induced cytidine deaminase
title_full_unstemmed Ago2 and a miRNA reduce Topoisomerase 1 for enhancing DNA cleavage in antibody diversification by activation-induced cytidine deaminase
title_short Ago2 and a miRNA reduce Topoisomerase 1 for enhancing DNA cleavage in antibody diversification by activation-induced cytidine deaminase
title_sort ago2 and a mirna reduce topoisomerase 1 for enhancing dna cleavage in antibody diversification by activation-induced cytidine deaminase
topic Biological Sciences
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10161001/
https://www.ncbi.nlm.nih.gov/pubmed/37094168
http://dx.doi.org/10.1073/pnas.2216918120
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