title: An autoregulatory mechanism imposes allosteric control on the V(D)J recombinase by histone H3 methylation.
abstract: V(D)J recombination is initiated by a specialized transposase consisting of the subunits RAG-1 and RAG-2. The susceptibility of gene segments to DNA cleavage by the V(D)J recombinase is correlated with epigenetic modifications characteristic of active chromatin, including trimethylation of histone H3 on lysine 4 (H3K4me3). Engagement of H3K4me3 by a plant homeodomain (PHD) in RAG-2 promotes recombination in vivo and stimulates DNA cleavage by RAG in vitro. We now show that H3K4me3 acts allosterically at the PHD finger to relieve autoinhibition imposed by a separate domain within RAG-2. Disruption of this autoinhibitory domain was associated with constitutive increases in recombination frequency, DNA cleavage activity, substrate binding affinity, and catalytic rate, thus mimicking the stimulatory effects of H3K4me3. Our observations support a model in which allosteric control of RAG is enforced by an autoinhibitory domain whose action is relieved by engagement of active chromatin.
authors.affiliation: Department of Molecular Biology and Genetics and Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Lu
authors.affiliation: Department of Molecular Biology and Genetics and Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Alyssa
authors.initials: A
authors.lastname: Ward
authors.affiliation: Department of Molecular Biology and Genetics and Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: John
authors.initials: J
authors.lastname: Bettridge
authors.affiliation: Department of Molecular Biology and Genetics and Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
authors.forename: Yun
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Molecular Biology and Genetics and Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. Electronic address: sdesider@jhmi.edu.
authors.forename: Stephen
authors.initials: S
authors.lastname: Desiderio
mesh_terms: D000818:Animals; D001665:Binding Sites; D002843:Chromatin / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D057809:HEK293 Cells; D056466:Histone Demethylases / Q000235:genetics / Q000378:metabolism; D006657:Histones / Q000235:genetics* / Q000378:metabolism; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008745:Methylation; D051379:Mice; D041681:NIH 3T3 Cells; D011485:Protein Binding; D060152:V(D)J Recombination / Q000235:genetics*; D045567:VDJ Recombinases / Q000235:genetics* / Q000378:metabolism
chemical_list: D002843:Chromatin; D004268:DNA-Binding Proteins; D006657:Histones; D018398:Homeodomain Proteins; C064655:V(D)J recombination activating protein 2; C064658:RAG-1 protein; D056466:Histone Demethylases; D045567:VDJ Recombinases