Transcriptional Control of AICDA Expression

AICDA 表达的转录控制

• 批准号: 6822944
• 负责人: FERENC LIVAK
• 金额: $ 7.43万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6822944
• 关键词: B lymphocyte; aminohydrolases; antigen antibody reaction; artificial chromosomes; binding sites; cell line; chromatin immunoprecipitation; clinical research; cytidine; gel mobility shift assay; gene expression; genetic models; genetic regulatory element; genetic transcription; genetically modified animals; green fluorescent proteins; laboratory mouse; model design /development; nuclease; polymerase chain reaction; protein binding; protein protein interaction; protein structure function; reporter genes; transcription factor

DESCRIPTION (provided by applicant): Immunoglobulin somatic hypermutation and class switch recombination increase the specificity and expand the functionality of the antibody repertoire in response to antigenic challenge to provide better protection against infections. Both processes involve highly ordered, temporal destabilization of the genome in mature B lymphocytes. Regulation of this genomic destabilization appears to be crucial in controlling lymphoid tumorgenesis. One important regulatory mechanism is the transcriptional control of expression of the activation-induced cytidine deaminase (AICDA) gene. AICDA provides a central catalytic activity to both hypermutation and class switch recombination, is the only known lymphoid-specific component of both processes and its transcription is predominantly restricted to germinal center B-lymphocytes. Characterization of the transcriptional control of AICDA gene expression is essential to understand the physiological regulation of hypermutation and class switch recombination and could illuminate potential pathological aberrations that lead to uncontrolled genomic instability and tumorgenesis. We have characterized the transcription of the AICDA gene in murine B-cell lines, determined the transcription start site in established cell lines and primary, splenic B-cells and identified a putative promoter of the AICDA gene which is evolutionarily conserved. In this application, we propose to perform experiments to: i) identify additional regulatory regions within the AICDA locus, ii) establish transgenic models to test the function of candidate regulatory elements, and iii) perform biochemical characterization of DNA-protein interactions of the regulatory elements in vivo to identify candidate transcription factors that may be critical in the control of AICDA expression. The results of this pilot proposal will allow us to begin studies on the cellular signal transduction pathways and transcriptional regulatory factors that control somatic hypermutation and class switch recombination of immunoglobulin genes.

描述（由申请方提供）：免疫球蛋白体细胞超突变和类别转换重组增加了特异性，并扩展了抗体库响应抗原激发的功能，以提供更好的抗感染保护。这两个过程都涉及成熟B淋巴细胞中基因组的高度有序的暂时不稳定。这种基因组不稳定的调节似乎是至关重要的控制淋巴肿瘤的发生。一个重要的调节机制是激活诱导的胞苷脱氨酶（AICDA）基因表达的转录控制。AICDA为超突变和类别转换重组提供了中心催化活性，是这两个过程中唯一已知的淋巴特异性组分，其转录主要限于生发中心B淋巴细胞。表征AICDA基因表达的转录控制对于理解超突变和类别转换重组的生理调节是必不可少的，并且可以阐明导致不受控制的基因组不稳定性和肿瘤发生的潜在病理畸变。我们已经表征了AICDA基因在小鼠B细胞系中的转录，确定了已建立的细胞系和原代脾B细胞中的转录起始位点，并鉴定了进化上保守的AICDA基因的推定启动子。在本申请中，我们提出进行实验以：i）鉴定AICDA基因座内的另外的调控区，ii）建立转基因模型以测试候选调控元件的功能，以及iii）进行体内调控元件的DNA-蛋白质相互作用的生物化学表征以鉴定可能在控制AICDA表达中至关重要的候选转录因子。这个试点提案的结果将使我们开始研究细胞信号转导途径和转录调控因子，控制体细胞超突变和类转换重组的免疫球蛋白基因。