Bolland Daniel J, Koohy Hashem, Wood Andrew L, Matheson Louise S, Krueger Felix, Stubbington Michael J T, Baizan-Edge Amanda, Chovanec Peter, Stubbs Bryony A, Tabbada Kristina, Andrews Simon R, Spivakov Mikhail, Corcoran Anne E
Nuclear Dynamics Programme, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK.
Bioinformatics Group, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK.
Cell Rep. 2016 Jun 14;15(11):2475-87. doi: 10.1016/j.celrep.2016.05.020. Epub 2016 Jun 2.
Variable (V), diversity (D), and joining (J) (V(D)J) recombination is the first determinant of antigen receptor diversity. Understanding how recombination is regulated requires a comprehensive, unbiased readout of V gene usage. We have developed VDJ sequencing (VDJ-seq), a DNA-based next-generation-sequencing technique that quantitatively profiles recombination products. We reveal a 200-fold range of recombination efficiency among recombining V genes in the primary mouse Igh repertoire. We used machine learning to integrate these data with local chromatin profiles to identify combinatorial patterns of epigenetic features that associate with active VH gene recombination. These features localize downstream of VH genes and are excised by recombination, revealing a class of cis-regulatory element that governs recombination, distinct from expression. We detect two mutually exclusive chromatin signatures at these elements, characterized by CTCF/RAD21 and PAX5/IRF4, which segregate with the evolutionary history of associated VH genes. Thus, local chromatin signatures downstream of VH genes provide an essential layer of regulation that determines recombination efficiency.
可变(V)、多样(D)和连接(J)(V(D)J)重组是抗原受体多样性的首要决定因素。要理解重组是如何被调控的,需要对V基因的使用情况进行全面、无偏差的读出。我们开发了VDJ测序(VDJ-seq),这是一种基于DNA的新一代测序技术,可对重组产物进行定量分析。我们揭示了在原代小鼠Igh基因库中,重组V基因之间的重组效率范围达200倍。我们利用机器学习将这些数据与局部染色质图谱整合,以识别与活跃的VH基因重组相关的表观遗传特征的组合模式。这些特征位于VH基因下游,并在重组过程中被切除,揭示了一类不同于表达调控的、控制重组的顺式调控元件。我们在这些元件上检测到两种相互排斥的染色质特征,其特征分别为CTCF/RAD21和PAX5/IRF4,它们与相关VH基因的进化历史相关。因此,VH基因下游的局部染色质特征提供了决定重组效率的关键调控层面。