MOUSE MODEL FOR OXIDATIVE DNA DAMAGE REPAIR

这项研究计划的长期目标是发现和了解突变途径，抵消这些途径的DNA修复过程，以及修复缺陷的后果。这一提议是对之前工作的延伸，此前的工作定义了细菌中新的“突变子菌株”，这些菌株具有比野生型更高的突变率，并导致阐明了氧化损伤的GO系统。人类突变基因是这一系统的重要组成部分，已经被克隆出来。这项工作现在已经扩展到包括靶向基因敲除小鼠。这项提议试图设计和描述一组缺乏氧化修复的基因敲除小鼠，以及缺乏不同修复酶组合的小鼠。缺乏特定的修复系统可能会导致癌症易感性。因此，确定氧化损伤修复系统的缺失是否会导致癌症发病率增加或其他异常，如加速衰老，这一点很重要。具体地说，拟议的研究试图做到以下几点。1.建立带有DNA修复基因mOGG1的mMYH双基因敲除小鼠。OGG1基因编码一种功能类似于细菌MutM蛋白的蛋白质。双重敲除可能会缺乏修复某些类型的DNA氧化损伤的能力。2.鉴定mMYH基因敲除小鼠和mMYH-/-mOGG1-/-双基因敲除小鼠，分析其表型，筛选氧化损伤修复能力降低可能导致的异常和癌症易感性。3.鉴定MYH-/-和MYH-/-OGG1-/-小鼠的胚胎成纤维细胞。4.建立和鉴定mMYH基因敲除小鼠与其他修复基因或肿瘤抑制基因敲除小鼠的额外组合，如MSH2和P53。

The long term goal of this research program is to uncover and understand mutational pathways, the DNA repair processes that counteract these pathways, and the consequences of repair defects. This proposal is an extension of previous work that defined new "mutator strains" in bacteria that have higher mutation rates than wild-type and that led to the elucidation of the GO system for oxidative damage. The human mutt gene, an essential component of this system, has been cloned. This work has now been extended to include targeted gene knockout mice. This proposal seeks to engineer and characterize a set of knockout mice lacking oxidative repair, as well as mice lacking different combinations of repair enzymes. Lacking certain repair systems can lead to cancer susceptibilities. It is therefore important to determine whether the absence of repair systems for oxidative damage leads to increased cancer rates or other abnormalities, such as accelerated aging. Specifically, the proposed research seeks to do the following. 1. Generate a double knockout mouse of mMYH with a DNA repair gene mOGG1. The OGG1 gene encodes a protein with a function similar to the bacterial MutM protein. Double knockouts might be expected to lack the ability to repair certain types of oxidative damage to the DNA. 2. Characterize mMYH knockout mice and mMYH-/- mOGG1-/- double knockout mice, analyze their phenotype and screen for abnormalities and cancer susceptibilities that might result from the reduced ability to repair oxidative damage. 3. Characterize primary mouse embryonic fibroblasts derived from both MYH-/- and MYH-/- OGG1-/- mice. 4. Generate and characterize additional combinations of mMYH knockout mice with other repair gene or tumor suppressor gene knockouts, such as MSH2 and p53.