Etiology of translocations in hematopoietic cells

造血细胞易位的病因学

• 批准号: 7116610
• 负责人: Christine A. Richardson
• 金额: $ 5.27万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7116610
• 关键词: DNA damage; DNA repair; cell differentiation; cell line; flow cytometry; fluorescent in situ hybridization; gene expression; genetic recombination; hematopoietic stem cells; microarray technology; molecular genetics; myeloid stem cell; polymerase chain reaction; southern blotting

DESCRIPTION (provided by applicant): The long-term objective of this research is to understand the influence of hematopoietic-specific developmental programs on the repair of one type of DNA damage--a double strand break (DSB)--and the initial molecular events that lead to translocations, which are a hallmark of leukemia, lymphoma, and soft-tissue sarcomas. Chromosomal DSBs are formed during normal metabolic processes including DNA replication and antigen receptor rearrangement in developing lymphoid cells, as well as following exposure to DNA damaging agents. There is an association between certain chemotherapeutic agents and secondary leukemia, e.g. treatment with topoisomerase II inhibitors and rearrangements involving 1lq23, and sequence analysis of breakpoints suggests that DNA damage is involved in the translocation process. However, the mechanisms by which specific translocations occur within developing hematopoietic subpopulations in the initial formation of rearrangements remain unclear. These questions can be addressed by adaptation of a genetic system developed in murine ES cells based on the rare-cutting yeast endonuclease I-Sce I to introduce DSBs at defined genomic loci and analyze recombinant repair events at the molecular level. This system also scores for translocations, duplications, and deletions that may result. This proposal will adapt the I-Sce I system to examine DSB repair and recombination in hematopoietic early progenitor and myeloid cell lineages and the potential for this type of damage to promote illegitimate recombination. Approaches will: (1) determine the potential for repair of DSBs and interchromosomal recombination to promote genome rearrangements within specific lineages; (2) determine the potential for repair of DSBs within the breakpoint cluster regions of the MLL and AF-4 genes to result in t(4;11) translocations similar to those observed in the clinical setting; and (3) use a genomics microarray-based approach to characterize the influence of the stage of hematopoietic development or the damaging agent on the specificity of a cell's DNA damage response. These studies will provide important insight into the biology of DSB rejoining in hematopoietic cell subpopulations, and the factors responsible for the normal suppression of genome rearrangements and, ultimately, tumorigenesis. Unraveling the etiology and consequences of translocations may lead to new approaches to therapy and prevention.

描述（由申请人提供）：本研究的长期目标是了解造血特异性发育程序对修复一种类型的 DNA 损伤（双链断裂 (DSB)）的影响以及初始分子导致易位的事件，这是白血病、淋巴瘤和软组织肉瘤的标志。 染色体 DSB 是在正常代谢过程中形成的，包括发育中的淋巴细胞中的 DNA 复制和抗原受体重排，以及暴露于 DNA 损伤剂后。某些化疗药物与继发性白血病之间存在关联，例如化疗药物。拓扑异构酶 II 抑制剂处理和涉及 1lq23 的重排以及断点的序列分析表明 DNA 损伤参与了易位过程。然而，在重排的初始形成过程中，发育中的造血亚群中发生特定易位的机制仍不清楚。 这些问题可以通过适应在鼠 ES 细胞中开发的基于稀切酵母核酸内切酶 I-Sce I 的遗传系统来解决，该系统在确定的基因组位点引入 DSB 并在分子水平分析重组修复事件。 该系统还对可能导致的易位、重复和删除进行评分。 该提案将采用 I-Sce I 系统来检查造血早期祖细胞和骨髓细胞谱系中的 DSB 修复和重组，以及此类损伤促进非法重组的可能性。 方法将：（1）确定 DSB 修复和染色体间重组的潜力，以促进特定谱系内的基因组重排； (2) 确定 MLL 和 AF-4 基因断点簇区域内 DSB 修复的潜力，从而导致与临床环境中观察到的类似的 t(4;11) 易位； (3) 使用基于基因组微阵列的方法来表征造血发育阶段或损伤剂对细胞 DNA 损伤反应特异性的影响。 这些研究将为造血细胞亚群中 DSB 重新连接的生物学以及负责正常抑制基因组重排并最终抑制肿瘤发生的因素提供重要的见解。揭示易位的病因和后果可能会带来新的治疗和预防方法。