DNA Structure Directed AID Deamination During Immunoglobulin Isotype Switching

免疫球蛋白同种型转换过程中 DNA 结构定向 AID 脱氨基作用

• 批准号: 9573844
• 负责人: Kefei Yu
• 金额: $ 38.07万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-24 至 2022-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9573844
• 关键词: Address; Affinity; Alligators; Antibodies; Antigens; B-Lymphocytes; Back; Binding; Binding Sites; Biochemical; Cells; Chinese People; Crystallization; Cytosine; DNA; DNA Double Strand Break; DNA Structure; Data; Deamination; Digestion; Engineering; Enzymes; Evaluation; G-Quartets; Genes; Genetic Recombination; Genetic Transcription; Guide RNA; Hybrids; Immunoglobulin Class Switching; Immunoglobulin Isotypes; Immunoglobulin Somatic Hypermutation; Immunoglobulin Switch Recombination; Immunoglobulins; In Vitro; Mammalian Cell; Mediating; Modeling; Mus; Mutate; Physiological; Process; Publishing; RNA; Reaction; Recombinant Proteins; Recombinants; Repetitive Sequence; Ribonuclease H; Ribonucleases; Role; Single-Stranded DNA; Specificity; Structure; Surface; Testing; Transcript; Uracil; Work; activation-induced cytidine deaminase; ds-DNA; in vivo; insight; mutant; novel; predictive modeling; quadruplex DNA; recombinase-mediated cassette exchange; ribonuclease H1; tool

Activation-induced cytidine deaminase (AID) catalyzes cytosine deamination (converting cytosine to uracil) at immunoglobulin (Ig) variable (V) and switch (S) regions in antigen- stimulated B cells to initiate somatic hypermutation (SHM) and class switch recombination (CSR). Recently, highly active monomeric recombinant AID has been generated and its crystal structure solved. Strikingly, the AID structure shows a bifurcated substrate-binding site; whereas recombinant AID avidly binds branched DNA structures, it only weakly binds ssDNA, which, until now, has been considered as the cognate substrate for AID in vivo. This groundbreaking discovery provides exceptional new insight into a collapsed R-loop model that we proposed several years ago. This untested model better explains many aspects of CSR. With new tools that we have developed in recent years, we propose to comprehensively test the hypothesis that the collapsed R-loop structure is the cognate substrate for AID during CSR.

活化诱导的胞苷脱氨酶（AID）催化胞嘧啶脱氨（转化为胞嘧啶脱氨）。 胞嘧啶至尿嘧啶）在抗原中的免疫球蛋白（IG）可变（V）和转换（S）区， 刺激B细胞启动体细胞超突变（SHM）和类别转换重组 （企业社会责任）。最近，已经产生了高活性的单体重组AID，并且其晶体 结构解决。引人注目的是，AID结构显示出分叉的底物结合位点;而 重组AID强烈地结合分支DNA结构，它仅微弱地结合ssDNA，直到 现在，已被认为是体内AID的同源底物。这项开创性 这一发现为我们提出的折叠R环模型提供了新的见解， 几年前这个未经检验的模型更好地解释了企业社会责任的许多方面。使用新工具 近年来，我们已经开发，我们建议全面测试的假设 折叠的R环结构是CSR期间AID的同源底物。