MOLECULAR ANALYSIS OF TEL AND TEL/AML1 IN PREB LEUKEMIA

描述：(改编自调查人员的摘要)最近， B系急性白血病患儿TEL/AML1融合基因的克隆 淋巴细胞白血病(ALL)。这种病是儿时最常见的疾病 癌症，在美国大约每10万名儿童中就有4名受到影响。 TEL/AML1是由12号染色体和2号染色体之间的染色体易位引起的 21，t(12：21)(PL13；Q22)。基因融合发生在TEL之间，位于 染色体12带p13，AML1，位于染色体21带q22。 虽然t(12；21)在细胞遗传学分析中很少见，但TEL/AML1 大约25%-30%的儿童ALL通过使用分子检测到融合 分析。此外，携带TEL/AML1的白血病细胞几乎总是 正常的TEL等位基因缺失。因此，t(12；21)是不寻常的，因为它 需要两种不同的突变来影响同一基因：失活 第二个TEL等位基因与AML1的融合。AML1 是一种DNA结合的反式激活剂，参与了其他几种不同的 与髓系白血病相关的易位。TEL是该协会的成员 Ets转录因子家族，包含一个螺旋-环-螺旋(HLH) N-末端的基序，蛋白质二聚所必需的。在工作中 假设TEL/AML1是一种改变的转录因子 不适当地影响与B细胞分化有关的基因。在……里面 支持这一假说，结果表明TEL/AML1抑制 由AML1激活。此外，调查人员认为，因为 HLH基序存在于正常的TEL和TEL/AML1融合中， 正常的TEL可能与TEL/AML1二聚化并使不适当的 嵌合基因的调控。这将解释如何逐步删除 正常的TEL等位基因。 该提案的长期目标是剖析分子 这种嵌合蛋白通过何种机制影响 造血细胞并导致白血病。中讨论的主要问题 这一建议是：哪些蛋白质与TEL/AML1相互作用？哪些基因起作用 它规范了吗？白血病是如何进展的？通过组合使用 生化和分子克隆技术以及组织培养研究， 研究人员将确定嵌合基因与哪些蛋白质结合 相互作用并评估它们在细胞转化中的作用。此外，他们还 将使用表达人类融合蛋白的转基因动物 以评估疾病的进展，并确定如何进行造血 基因受到嵌合蛋白的影响。 该提案中概述的实验将使他们能够开始 TELL/AML1在造血中的作用及其在骨髓瘤中的作用 白血病的形成。

DESCRIPTION: (adapted from the investigator's abstract) Recently, the fusion gene TEL/AML1 was cloned from children with B-lineage acute lymphoblastic leukemia (ALL). This disease is the most common childhood cancer, and it affects about 4 in 100,000 children in the United States. TEL/AML1 results from a chromosomal translocation between chromosomes 12 and 21, the t(12:21)(pl13;q22). Gene fusion occurs between TEL, located at chromosome 12 band p13, and AML1, located on chromosome 21 band q22. Although the t(12;21) is rarely seen by cytogenetic analysis, the TEL/AML1 fusion is detected in about 25-30% of childhood ALL by using molecular analysis. In addition, almost always the leukemic cells with TEL/AML1 have deletion of the normal TEL allele. Thus, the t(12;21) is unusual in that it requires two different mutations affecting the same gene: the inactivation of one allele of TEL, and the fusion of the second TEL allele to AML1. AML1 is a DNA-binding transactivator involved in several other different translocations associated with myeloid leukemias. TEL is a member of the ETS family of transcription factors and contains a helix-loop-helix (HLH) motif at the N-terminal, necessary for protein dimerization. The working hypothesis is that TEL/AML1 is an altered transcription factor that inappropriately affects genes involved in B cell differentiation. In support of this hypothesis, results show that TEL/AML1 represses the activation by AML1. In addition, the investigators believe that, because the HLH motif is present in the normal TEL and in the TEL/AML1 fusion, the normal TEL might dimerize with TEL/AML1 and inactivate the inappropriate regulation by the chimeric gene. This would explain progressive deletion of the normal TEL allele. The long term objective of the proposal is to dissect the molecular mechanisms by which this chimeric protein affects the development of the hematopoietic cell and leads to leukemia. The major questions addressed in this proposal are: What proteins interact with TEL/AML1? Which genes does it regulate? and How does the leukemia progress? By using a combination of biochemical and molecular cloning techniques and tissue culture studies, the investigator will identify the proteins with which the chimeric genes interact and assess their role in cell transformation. Furthermore, they will use genetically altered animals which express the human fusion protein to evaluate the progress of the disease and to determine how hematopoietic genes are affected by the chimeric proteins. The experiments outlined in this proposal will allow them to begin to dissect the effects of TEL/AML1 in hematopoiesis and its contribution to leukogenesis.