MAPPING AND CLONING TRANSLOCATION BREAKPOINTS

描述：(改编自申请人的摘要)来自人类的恶性细胞 白血病和淋巴瘤的染色体异常频率很高， 尤其是易位。仔细的细胞遗传学分析定义了 反复发生的染色体重排的断点，这一直是主要的 一种工具，可用于识别与白血病和 淋巴瘤。白血病染色体易位断裂点的定位和克隆， 淋巴瘤和肉瘤是发现新的 在造血细胞恶性转化中起重要作用的基因。 尽管白血病中大多数常见的反复重排都是 克隆，罕见重排的作图和克隆继续提供 丰富的生物相关信息。 这个项目的长期目标是识别新的基因 白血病和淋巴瘤。该策略将使用易位断点来 利用已定义的基因组识别相关基因的染色体位置 探针和荧光原位杂交(FISH)。样本中包含 恶性细胞将从两组进行分析。第一组将是 已知有MLL、TEL或AML1重排的患者(特定目标1)。 这三个基因在人类急性白血病中非常重要，在 其他血液病。他们已经被证明参与了 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，其中断不涉及MLL、TEL或AML1 (具体目标2)。这三个地区的重组断点将是 使用FISH绘制地图，以确定它们中的任何一个是否聚集在特定的 地点。对于双方都不知道的易位，探针 将对分裂的基因进行鉴定，以确定涉及的基因。DNA探针 是否适合这些基因将被用来确定这些“新”基因是否 在具有相同断点的样本中参与其他重排。 不同的cdna选择策略将被用来克隆相关基因。 以及伴侣基因。这项研究将确定涉及到 根据过去的结果，这些基因中的大多数将是新的基因 他们的鉴定将丰富我们对复杂基因的理解 涉及造血细胞恶变的变化。 这些基因的识别为我们提供了非常宝贵的资源 临床医学，因为它们被用来提高诊断的准确性 用它可以确定恶性细胞的基因型。此外， 特殊的细胞遗传学异常具有非常重要的预后意义 根据患者的核型对患者进行分层治疗 恶性细胞。我们发现的易位越多，就越完整 将是我们的诊断测试。尤其是随着DNA芯片的出现 技术，我们可以筛查所有的融合基因和预后 即使是罕见的重组，其影响也是可以确定的。在未来， 当我们对这些基因的生物学有了足够的了解时，我们就可以 希望开发出基因特异性治疗方法。

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.