Mechanisms of Genomic Change

所有细胞都需要尽量减少其遗传信息的变化。遗传变化的潜力在整个基因组中并不均匀：有些序列本质上更易变。从细菌到人类的不完美反向重复序列中发现了突变热点。在这些位点的诱变机制涉及聚合酶模板转换，由此复制链重新排列，并且突变变化是从反向重复序列中的其他序列模板化的。这一过程可能会驱动许多基因组中丰富的反向重复序列的形成。尽管这一过程的普遍性和普遍性，但人们对促进突变或避免突变的因素知之甚少。利用大肠杆菌thyA基因中的天然突变热点，该项目将确定控制模板转换诱变的因素，这一过程可能会影响所有基因组。该位点异常高的诱变率为筛选影响热点诱变的基因提供了独特的机会。这种方法将为诱变和避免突变的机制提供新的见解。其他实验试图澄清染色体背景或复制叉的损伤是否会影响此类事件的频率。本科生和研究生将执行拟议的实验和实验室有本科生的参与，以及研究生，学生在研究的良好记录。因此，该提案的一个更广泛的影响是对学生进行最先进的遗传分析培训，并为他们在公共或私营部门的研究和教育事业提供指导。

All cells need to minimize changes to their genetic information. The potential for genetic change is not uniform across the genome: some sequences are intrinsically more mutable. Mutational hotspots are found in imperfect inverted repeat sequences from bacteria to humans. The mechanism for mutagenesis at these sites involves a polymerase template switch, whereby the replicating strand realigns and the mutational changes are templated from other sequences in the inverted repeat. This process may drive the formation of inverted repeat sequences, abundant in many genomes. Despite the prevalence and universality of this process, little is known about factors that promote mutation or act to avoid them. Using a natural mutational hotspot in the thyA gene of Escherichia coli, this project will identify the factors that control template-switch mutagenesis, a process that likely impacts all genomes. The unusually high rate of mutagenesis at this site provides a unique opportunity to screen for genes that influence hotspot mutagenesis. This approach will provide new insights into the mechanism of mutagenesis and mutation avoidance. Other experiments seek to clarify whether chromosomal context or damage to the replication fork affects the frequency of such events. Undergraduate and graduate students will perform the proposed experiments and the laboratory has a strong track record of the participation of undergraduate, as well as graduate, students in research. A broader impact of the proposal, therefore, is the training of students in state-of-the art genetic analysis and their mentorship for careers in research and education in the public or private sector.