THE PML-RAR ONCOGENIC FUSION PROTEIN AND ITS ROLE IN ACUTE PROMYELOCYTIC LEUKEMI

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 急性早幼粒细胞白血病(APL)是由15号和17号染色体之间的一种特殊的相互易位引起的。易位融合了PML肿瘤抑制基因和维甲酸受体a(RAR A)，产生了一种PML-RARA嵌合癌蛋白，干扰了与髓系分化相关的信号转导。APL患者接受全反式维甲酸(ATRA)治疗，但由于融合蛋白RARA部分的配体结合域(LBD)突变导致ATRA耐药，患者总是复发。这些突变分别影响蛋白质与维甲酸结合的能力，以及核共抑制蛋白(N-COR)和共激活蛋白(ACTR)的释放和结合。这些辅因子在RARA转录功能中起着重要作用。我们建立了荧光各向异性和共振能量转移分析来定量在不同浓度的ATRA存在下，辅助激活因子和辅助抑制因子多肽与野生型Rara LBD和四个ATRA抗性突变体的结合。通过使用这些分析，我们已经确定了辅因子解离常数，并根据辅因子募集确定了这些患者和细胞系突变的ATRA耐药基础。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Acute Promyelocytic Leukemia (APL) results from a specific reciprocal translocation between chromosomes 15 and 17. The translocation fuses the genes for the PML tumor suppressor and retinoic acid receptor a (RARa), generating a PML-RARa chimeric oncoprotein that interferes with signaling associated with myeloid differentiation. APL patients receive treatment with all-trans retinoic acid (ATRA), but invariably undergo relapse owing to mutations imparting ATRA resistance in the ligand binding domain (LBD) of the RARa portion of the fusion protein. The mutations affect the ability of the protein to bind retinoic acid, as well as undergo release and binding of nuclear co-repressor (N-CoR) and co-activator (ACTR) proteins, respectively. These cofactors play essential roles in RARa transcription function. We developed fluorescence anisotropy and resonance energy transfer assays to quantitate the binding of coactivator and corepressor peptides to the wild-type RARa LBD and four ATRA resistant mutants in the presence of varying concentrations of ATRA. By use of these assays, we have determined cofactor dissociation constants and defined the basis of ATRA resistance in these patient and cell line mutations in terms of cofactor recruitment.