Myb protein specificity in human hematopoietic cells

描述（由申请人提供）：本修订后的申请旨在比较正常细胞和白血病细胞表达的c-Myb的野生型和变异版本的活性，并确定其与人类疾病的相关性。c-myb原癌基因编码具有潜在转化活性的DNA结合转录因子。c-Myb蛋白相对较小的变化释放了它在鸟类和啮齿动物中引起白血病的能力，微阵列分析表明，即使是c端结构域的微小变化也会导致转录活性的巨大变化。选择性RNA剪接产生多个c-myb mrna，编码c端结构域改变的蛋白质，与正常细胞相比，白血病细胞中的选择性剪接更丰富、更多样化，这表明c-myb的变体可能参与了白血病的发生。

DESCRIPTION (provided by applicant): This revised application proposes to compare the activities of the wild type and variant versions of c-Myb expressed by normal cells and leukemias, and to determine their relevance to human disease. The c-myb proto-oncogene encodes a DNA binding transcription factor with latent transforming activity. Relatively minor changes to the c-Myb protein unleash its ability to cause leukemias in birds and rodents and microarray assays have shown that even minor changes to its C-terminal domains result in dramatic changes in transcriptional activity. Alternative RNA splicing generates multiple c-myb mRNAs that encode proteins with altered C-terminal domains and the alternative splicing is more abundant and more varied in leukemias than in normal cells, suggesting that variants of c-Myb may participate in leukemogenesis. In Aim 1, the structures of the most abundant variant c-myb mRNAs expressed in a representative group of normal hematopoietic cells and leukemias will be determined. To compare their activities, the normal and variant forms of c-Myb will be expressed in human monocytes and microarray assays will be used to identify telltale changes in gene expression. Aim 2 will test the biological relevance of the variant c-Myb proteins. First, alternative splicing of c-myb gene products will be studied in differentiating hematopoietic cells, then wild type and variant c-Myb proteins will be expressed in normal hematopoietic progenitors, to see if changes in differentiation or proliferation are induced. In Aim 3, quantitative assays will be used to follow the expression of normal and variant c-myb RNAs in a defined cohort of adult AML samples, and then statistical analyses will determine whether specific variants correlate with clinical parameters, prognosis or gene expression patterns in AML patient samples. The proposed experiments build on our expertise and extensive preliminary and published data and have great relevance to the study of alternative RNA splicing, the activity of Myb proteins and human leukemia.