VDJ RECOMBINATION EFFECT ON SCID B CELL DEVELOPMENT

描述（改编自研究者摘要）：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 从单独的V（可变）-，D（多样性）-和J（连接）-基因片段 通过一个叫做“V（D）J重组”的过程。 V（D）J复合 涉及位点特异性切割以产生双链断裂， 这些断裂的不精确的端部连接。 这种重组中的缺陷可以 导致一种称为严重联合免疫缺陷病综合征 （SCID）。 受影响的人缺乏功能性T细胞和B细胞。 的scid 小鼠突变导致双链断裂修复缺陷。 细胞 这种缺陷表现出对DNA损伤剂的超敏反应 (such例如，γ辐射）以及无法连接V、D和J元素。 与DNA损伤剂类似，V（D）J重组的启动可能是 由于未分辨DNA的积累，对scid淋巴细胞有害 休息. 这些断裂也可能是二次重组的目标 导致染色体缺失和易位。 因此， 重组相关断裂的解决可能有助于 淋巴恶性肿瘤的发病机制。 直接调查 重组相关断裂对存活、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 通过体外操作诱导。 一个系统涉及使用 温度敏感性转化的前B细胞系。 另一种是利用 在白细胞介素-7（IL-7）存在下的祖细胞/基质细胞培养。 具体而言，我们提出：1）检查scid淋巴细胞如何解决双 由于V（D）J重组而原位产生的链断裂; 2） 确定未解决的断裂如何在体外影响SCID细胞;和3） 研究bcl-2转基因如何影响细胞的存活和分化， 带有破损的scid B淋巴细胞。 这项研究的长期目标是 识别V（D）J重组在发病机制中的作用 免疫缺陷和淋巴恶性肿瘤。 结果应该提供新的 对这些免疫缺陷的早期检测和干预的见解 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.