VDJ RECOMBINATION EFFECT ON SCID B CELL DEVELOPMENT

描述(改编自《调查者摘要》)：抗原结合 免疫球蛋白和T细胞受体的区域是体细胞组装的 来自单独的V(可变)、D(多样性)和J(连接)基因片段 通过一个称为“V(D)J重组”的过程。V(D)J复合 涉及特定部位的切割以产生双链断裂和 这些断口的端部连接不精确。这种重组中的缺陷可能 导致一种称为严重联合免疫缺陷的疾病综合征 (SCID)。受影响的个体缺乏功能正常的T和B细胞。SCID 小鼠的突变导致双链断裂修复的缺陷。单元格 这种缺陷表现出对DNA损伤剂的过敏性 (例如，伽马辐射)和不能连接V、D和J元素。 与DNA损伤剂类似，V(D)J重组的启动可能是 未溶解DNA积聚对SCID淋巴细胞有害 休息一下。这些断裂也可能成为二次重组的目标。 这会导致染色体缺失和易位。因此，反常的 重组相关断裂的解决可能有助于 淋巴系统恶性肿瘤的发病机制。直接调查其影响 重组相关突变对生存、生长和分化的影响 对于正常和SCID淋巴细胞，我们将采用两种培养系统 VDJ重组或B细胞分化的激活可以是什么 由体外操作诱导。一种系统涉及使用 温度敏感型转化的前B细胞系。另一种是利用 祖细胞/基质细胞在白介素7(IL-7)存在下培养。 具体地说，我们建议：1)研究SCID淋巴细胞如何分解双重 V(D)J重组导致的原位断裂；2) 确定未解决的断裂如何影响体外培养的SCID细胞；以及3) 研究bcl2转基因对人卵巢癌细胞存活和分化的影响 具有破裂功能的SCID B淋巴细胞。这项研究的长期目标是 V(D)J重组在慢性粒细胞白血病发病机制中的作用 免疫缺陷和淋巴系统恶性肿瘤。结果应该会提供新的 对这些免疫性疾病的早期检测和干预的启示 疾病。

DESCRIPTION (Adapted from the Investigator's abstract): The antigen-binding regions of immunoglobulins and T-cell receptors are somatically assembled from separate V (variable)-, D (diversity)- and J (joining)-gene segments through a process called "V(D)J recombination". V(D)J recombination involves site-specific cleavages to generate double-strand breaks and imprecise end joinings of these breaks. Defects in this recombination can lead to a disease syndrome known as severe combined immune deficiency (SCID). Affected individuals lack functional T- and B-cells. The scid mouse mutation results in a defect in double-strand break repair. Cells with such a defect manifest both a hypersensitivity to DNA damaging agents (such as, gamma-irradiation) and an inability to join V, D and J elements. Similar to DNA damaging agents, initiation of V(D)J recombination could be deleterious to scid lymphocytes due to accumulation of unresolved DNA breaks. These breaks could also be targets for secondary recombination which lead to chromosomal deletions and translocations. Thus, aberrant resolution of recombination-associated breaks is likely to contribute to the pathogenesis of lymphoid malignancies. To directly investigate the effect of recombination-associated breaks on survival, growth and differentiation of both normal and scid lymphocytes, we will employ two culture systems in which activation of VDJ recombination or B-cell differentiation can be induced by in vitro manipulation. One system involves the use of temperature sensitive transformed pre-B-cell lines. The other makes use of progenitors/stromal cell culture in the presence of interleukin-7 (IL-7). Specifically, we propose: 1) to examine how scid lymphocytes resolve double strand breaks made in situ as a result of V(D)J recombination; 2) to determine how unresolved breaks may affect scid cells in vitro; and 3) to investigate how a bcl-2 transgene influences survival and differentiation of break-bearing scid B lymphocytes. The long term goal of this research is to discern the role of V(D)J recombination in the pathogenesis of immunodeficiency and lymphoid malignancies. The results should provide new insights for earlier detection and intervention of these immunological diseases.