Publication Date:
2015-08-27
Description:
During B-cell development, RAG endonuclease cleaves immunoglobulin heavy chain (IgH) V, D, and J gene segments and orchestrates their fusion as deletional events that assemble a V(D)J exon in the same transcriptional orientation as adjacent Cmu constant region exons. In mice, six additional sets of constant region exons (CHs) lie 100-200 kilobases downstream in the same transcriptional orientation as V(D)J and Cmu exons. Long repetitive switch (S) regions precede Cmu and downstream CHs. In mature B cells, class switch recombination (CSR) generates different antibody classes by replacing Cmu with a downstream CH (ref. 2). Activation-induced cytidine deaminase (AID) initiates CSR by promoting deamination lesions within Smu and a downstream acceptor S region; these lesions are converted into DNA double-strand breaks (DSBs) by general DNA repair factors. Productive CSR must occur in a deletional orientation by joining the upstream end of an Smu DSB to the downstream end of an acceptor S-region DSB. However, the relative frequency of deletional to inversional CSR junctions has not been measured. Thus, whether orientation-specific joining is a programmed mechanistic feature of CSR as it is for V(D)J recombination and, if so, how this is achieved is unknown. To address this question, we adapt high-throughput genome-wide translocation sequencing into a highly sensitive DSB end-joining assay and apply it to endogenous AID-initiated S-region DSBs in mouse B cells. We show that CSR is programmed to occur in a productive deletional orientation and does so via an unprecedented mechanism that involves in cis Igh organizational features in combination with frequent S-region DSBs initiated by AID. We further implicate ATM-dependent DSB-response factors in enforcing this mechanism and provide an explanation of why CSR is so reliant on the 53BP1 DSB-response factor.〈br /〉〈br /〉〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4592165/" target="_blank"〉〈img src="https://static.pubmed.gov/portal/portal3rc.fcgi/4089621/img/3977009" border="0"〉〈/a〉 〈a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4592165/" target="_blank"〉This paper as free author manuscript - peer-reviewed and accepted for publication〈/a〉〈br /〉〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Dong, Junchao -- Panchakshari, Rohit A -- Zhang, Tingting -- Zhang, Yu -- Hu, Jiazhi -- Volpi, Sabrina A -- Meyers, Robin M -- Ho, Yu-Jui -- Du, Zhou -- Robbiani, Davide F -- Meng, Feilong -- Gostissa, Monica -- Nussenzweig, Michel C -- Manis, John P -- Alt, Frederick W -- AI037526/AI/NIAID NIH HHS/ -- AI072529/AI/NIAID NIH HHS/ -- AI077595/AI/NIAID NIH HHS/ -- AI112602/AI/NIAID NIH HHS/ -- CA133781/CA/NCI NIH HHS/ -- R01 AI077595/AI/NIAID NIH HHS/ -- R21 AI088510/AI/NIAID NIH HHS/ -- R21 CA133781/CA/NCI NIH HHS/ -- T32HL066987/HL/NHLBI NIH HHS/ -- Howard Hughes Medical Institute/ -- England -- Nature. 2015 Sep 3;525(7567):134-9. doi: 10.1038/nature14970. Epub 2015 Aug 26.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, and Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA. ; Boston Children's Hospital and Joint Program in Transfusion Medicine, Harvard Medical School, Boston, Massachusetts 02115, USA. ; Howard Hughes Medical Institute, Laboratory of Molecular Immunology, The Rockefeller University, New York, New York 10065, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26308889" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Ataxia Telangiectasia Mutated Proteins/metabolism
;
B-Lymphocytes/enzymology/immunology/*metabolism
;
Chromosomal Proteins, Non-Histone/metabolism
;
Cytidine Deaminase/*metabolism
;
*DNA Breaks, Double-Stranded
;
DNA Repair/*genetics
;
DNA-Binding Proteins/metabolism
;
Deamination
;
Immunoglobulin Class Switching/*genetics
;
Immunoglobulin Constant Regions/*genetics
;
Immunoglobulin Heavy Chains/*genetics
;
Mice
;
Sequence Deletion/genetics
;
VDJ Exons/genetics
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
Permalink
