MAPPING AND CLONING TRANSLOCATION BREAKPOINTS

描述：（改编自申请人摘要）来自人的恶性细胞 白血病和淋巴瘤具有非常高频率的染色体异常， 尤其是易位。仔细的细胞遗传学分析已经确定了 染色体重排中的断裂点，这一直是主要的 导致识别白血病关键基因的工具， 淋巴瘤白血病染色体易位断裂点的定位和克隆， 淋巴瘤和肉瘤一直是发现新的 在造血细胞恶性转化中重要的基因。 尽管大多数常见的白血病复发性重排已经被证实是一种恶性肿瘤， 克隆，罕见重排的定位和克隆继续提供了一个新的方法。 丰富的生物学相关信息。 该项目的长期目标是确定参与 白血病和淋巴瘤。该策略将使用易位断点， 使用定义的基因组序列确定相关基因的染色体位置 探针和荧光原位杂交（FISH）。样品含有 将分析来自两组的恶性细胞。第一组将是 已知有MLL、TEL或AML 1（特异性目的1）重排的患者。 这三个基因在人类急性白血病以及 其他血液病。他们被证明参与了 与许多其他基因的易位。克隆这些伴侣基因， 发现了大量以前未知的基因，这些基因在 造血细胞的转化。第二组包括患有 11q、12p和21q中的断点，其断点不涉及MLL、TEL或AML 1 （具体目标2）。这三个区域的重排断点将 使用FISH进行映射，以确定它们中的任何一个是否聚集在特定的 位置.对于伴侣基因均未知的易位，探针 将被鉴定以确定所涉及的基因。DNA探针 将用于确定这些“新”基因是否 在具有相同断点的样品中参与其他重排。 将使用各种cDNA选择策略来克隆相关基因， 以及伴侣基因。这项研究将确定基因参与 根据过去的研究结果，这些基因中的大多数将是新的基因 它的鉴定将丰富我们对复杂的遗传 造血细胞恶性转化的变化。 这些基因的鉴定为人类提供了非常宝贵的资源， 临床医学，因为它们用于提高诊断精度 利用该方法可以确定恶性细胞的基因型。此外，委员会认为， 特定的细胞遗传学异常具有非常大的预后意义， 根据患者的染色体核型对患者进行分层治疗， 恶性细胞我们能识别的易位越多， 将是我们的诊断测试尤其是随着DNA芯片的出现 技术，我们可以筛选所有的融合基因和预后 即使是罕见的重排的影响也可以确定。在未来， 当我们对这些基因的生物学有了足够的了解， 希望开发基因型特异性治疗。

DESCRIPTION: (adapted from the applicant's abstract) Malignant cells from human leukemia and lymphoma have a very high frequency of chromosome abnormalities, especially translocations. Careful cytogenetic analysis has defined the breakpoints in recurring chromosome rearrangements, and this has been the major tool leading to identification of genes critically involved in leukemia and lymphoma. Mapping and cloning chromosome translocation breakpoints in leukemia, lymphoma and sarcoma have been one of the most efficient ways to discover new genes that are important in malignant transformation of hematopoietic cells. Although most of the common recurring rearrangements in leukemia have been cloned, the mapping and cloning of rare rearrangements continues to provide a wealth of biologically relevant information. The long-term goal of this project is to identify new genes involved in leukemia and lymphoma. The strategy will be to use translocation breakpoints to identify the chromosome location of the involved genes using defined genomic probes and fluorescence in situ hybridization (FISH). Samples containing malignant cells will be analyzed from two groups. The first group will be patients known to have rearrangements of MLL, TEL, or AML1 (Specific Aim 1). These three genes are very important in human acute leukemia as well as in other hematologic diseases. They have been shown to be involved in translocations with many other genes. Cloning these partner genes has identified a large number of previously unknown genes that play a role in transformation of hematopoietic cells. The second group includes patients with breakpoints in 11q, 12p, and 21q whose breaks do not involve MLL, TEL or AML1 (Specific Aim 2). The breakpoints of rearrangements in these three regions will be mapped using FISH to determine whether any of them cluster in a particular location. For translocations in which neither partner gene is known, probes that are split will be identified to determine the involved gene. DNA probes appropriate for the genes will be used to determine whether these "new" genes are involved in other rearrangements in samples that have the same breakpoint. Various cDNA selection strategies will be used to clone the involved gene as well as the partner gene. This research will identify genes involved in leukemogenesis and based on past results, most of these will be novel genes whose identification will enrich our understanding of the complex genetic changes involved in malignant transformation of hematopoietic cells. Identification of these genes has provided a very valuable resource for clinical medicine because they are used to improve the diagnostic precision with which the genotype of the malignant cells can be determined. Moreover, particular cytogenetic abnormalities have very great prognostic implications so that patients are stratified for treatment based on the karyotype of their malignant cells. The more translocations we can identify, the more complete will be our diagnostic tests. Especially with the advent of DNA chip technology, we could screen for all of the fusion genes and the prognostic implications of even rare rearrangements could be determined. In the future, when we have sufficient understanding of the biology of these genes, we can hope to develop genotypic specific treatment.