小柯机器人

科学家绘制出人类淋巴细胞中多样化的突变图谱
2022-08-13 23:39

英国剑桥大学Peter J. Campbell、David G. Kent等研究人员合作绘制出人类淋巴细胞中多样化的突变图谱。相关论文于2022年8月10日在线发表在《自然》杂志上。

在开发了单细胞淋巴细胞培养物的扩增方案后,研究人员对717个正常的初始和记忆B细胞和T细胞以及造血干细胞的全基因组进行了测序。所有的淋巴细胞亚群都比造血干细胞携带更多的点突变和结构变异,记忆细胞的负担比初始细胞高,而T细胞在整个生命中积累突变的速度更高。免疫学多样化的脱靶效应占了淋巴细胞额外分化相关突变的大约一半。
 
记忆B细胞在生发中心反应期间,平均每一个目标IGHV突变在整个基因组中获得18个脱靶突变。淋巴细胞的结构变异比干细胞高16倍,大约15%的缺失可归因于脱靶重组酶激活基因的活性。紫外线照射造成的DNA损伤和其他零星的突变过程在一些记忆细胞中产生了数百至数千的突变。正常B细胞的突变负担和特征与许多B细胞癌症中的突变大致相似,这表明淋巴细胞的恶性转化产生于整个正常发育过程中活跃的相同突变过程。正常淋巴细胞的突变图谱记录了免疫学多样化过程中程序化基因组工程的脱靶效应,以及分化、增殖和驻留在不同微环境中的后果。
 
据介绍,淋巴细胞的基因组容易受到许多威胁,包括分化过程中的程序性突变、抗原驱动的增殖和在不同微环境中的驻留。
 
附:英文原文
 
Title: Diverse mutational landscapes in human lymphocytes

Author: Machado, Heather E., Mitchell, Emily, bro, Nina F., Kbler, Kirsten, Davies, Megan, Leongamornlert, Daniel, Cull, Alyssa, Maura, Francesco, Sanders, Mathijs A., Cagan, Alex T. J., McDonald, Craig, Belmonte, Miriam, Shepherd, Mairi S., Vieira Braga, Felipe A., Osborne, Robert J., Mahbubani, Krishnaa, Martincorena, Iigo, Laurenti, Elisa, Green, Anthony R., Getz, Gad, Polak, Paz, Saeb-Parsy, Kourosh, Hodson, Daniel J., Kent, David G., Campbell, Peter J.

Issue&Volume: 2022-08-10

Abstract: The lymphocyte genome is prone to many threats, including programmed mutation during differentiation1, antigen-driven proliferation and residency in diverse microenvironments. Here, after developing protocols for expansion of single-cell lymphocyte cultures, we sequenced whole genomes from 717 normal naive and memory B and T cells and haematopoietic stem cells. All lymphocyte subsets carried more point mutations and structural variants than haematopoietic stem cells, with higher burdens in memory cells than in naive cells, and with T cells accumulating mutations at a higher rate throughout life. Off-target effects of immunological diversification accounted for approximately half of the additional differentiation-associated mutations in lymphocytes. Memory B cells acquired, on average, 18 off-target mutations genome-wide for every on-target IGHV mutation during the germinal centre reaction. Structural variation was 16-fold higher in lymphocytes than in stem cells, with around 15% of deletions being attributable to off-target recombinase-activating gene activity. DNA damage from ultraviolet light exposure and other sporadic mutational processes generated hundreds to thousands of mutations in some memory cells. The mutation burden and signatures of normal B cells were broadly similar to those seen in many B-cell cancers, suggesting that malignant transformation of lymphocytes arises from the same mutational processes that are active across normal ontogeny. The mutational landscape of normal lymphocytes chronicles the off-target effects of programmed genome engineering during immunological diversification and the consequences of differentiation, proliferation and residency in diverse microenvironments.

DOI: 10.1038/s41586-022-05072-7

Source: https://www.nature.com/articles/s41586-022-05072-7

Nature:《自然》,创刊于1869年。隶属于施普林格·自然出版集团,最新IF:69.504
官方网址:http://www.nature.com/
投稿链接:http://www.nature.com/authors/submit_manuscript.html


本期文章:《自然》:Online/在线发表

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