Regulation of the Pax-5 Proto-Oncogene

Pax-5 原癌基因的调控

• 批准号: 6769090
• 负责人: James R. Hagman
• 金额: $ 13.64万
• 依托单位: NATIONAL JEWISH HEALTH
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2006-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6769090
• 关键词: B cell lymphoma; DNA binding protein; cysteine; gene targeting; genetically modified animals; humoral immunity; laboratory mouse; matrix assisted laser desorption ionization; molecular genetics; oxidation reduction reaction; oxidative stress; posttranslational modifications; protein structure function

DESCRIPTION (provided by applicant): The Pax family of DNA-binding proteins includes essential regulators of tissue-specific gene expression in humans and other higher eukaryotes. Pax proteins are essential for the formation of differentiated cells and tissues, however, increasing levels of DNA binding activity results in neoplastic transformation and tumorigenesis. For example, chromosomal abnormalities and gene rearrangements resulting in overexpression of Pax-5 are associated with B lineage lymphomas in humans. Mechanisms contributing to Pax-5-mediated lymphomagenesis are not understood, but multiple lines of evidence suggest that the dosage of Pax-5 is exquisitely regulated in normal B cells by transcriptional and post-translational mechanisms. As one mechanism contributing to post-translational regulation of Pax-5, we propose that Pax- 5 DNA binding is regulated, in part, by the redox status of highly conserved cysteine residues in its paired DNA-binding domain. Thus, DNA binding by Pax-5 (and other Pax family members) may be reduced in response to oxidative stress. To date, this hypothesis has only been tested using limited in vitro model systems that do not adequately reflect the complexity of homeostatic mechanisms governing transcriptional activity in vivo. Moreover, it has not been determined whether S-thiolation (glutathionylation) of Pax-5 is an important mechanism for controlling its activity in vivo. In this application, we propose a genetic approach that bypasses previously encountered deficiencies associated with transfection assays and other in vitro experimental protocols. Our experiments will address a relatively unexplored area of molecular biology with profound implications for understanding how cells maintain precise levels of key regulatory factors. Our studies will eventually aid in devising new therapeutics for treating Pax-related cancers (lymphoma, astrocytoma, and rhabdomyosarcoma).

描述（由申请人提供）：DNA结合蛋白的Pax家族包括人类和其他高等真核生物中组织特异性基因表达的重要调节因子。 Pax 蛋白对于分化细胞和组织的形成至关重要，然而，DNA 结合活性水平的增加会导致肿瘤转化和肿瘤发生。例如，导致 Pax-5 过度表达的染色体异常和基因重排与人类 B 系淋巴瘤相关。 Pax-5 介导的淋巴瘤发生的机制尚不清楚，但多种证据表明 Pax-5 的剂量在正常 B 细胞中受到转录和翻译后机制的精细调节。作为有助于 Pax-5 翻译后调节的一种机制，我们提出 Pax-5 DNA 结合部分受到其配对 DNA 结合域中高度保守的半胱氨酸残基的氧化还原状态的调节。因此，Pax-5（和其他 Pax 家族成员）的 DNA 结合可能会因氧化应激而减少。迄今为止，这一假设仅使用有限的体外模型系统进行了测试，这些系统不能充分反映控制体内转录活性的稳态机制的复杂性。此外，尚未确定Pax-5的S-硫醇化（谷胱甘肽化）是否是控制其体内活性的重要机制。在此应用中，我们提出了一种遗传方法，可以绕过以前遇到的与转染测定和其他体外实验方案相关的缺陷。我们的实验将解决分子生物学中相对未探索的领域，对于理解细胞如何维持关键调节因子的精确水平具有深远的影响。我们的研究最终将有助于设计新的疗法来治疗 Pax 相关癌症（淋巴瘤、星形细胞瘤和横纹肌肉瘤）。