Mechanisms of Genomic Change

所有细胞都需要最大限度地减少其遗传信息的变化。基因改变的可能性在整个基因组中并不是一致的：一些序列本质上更具变异性。突变热点是在从细菌到人类的不完美反向重复序列中发现的。这些位点的突变机制涉及聚合酶模板开关，由此复制的链重新排列，突变变化以反向重复中的其他序列为模板。这一过程可能会驱动反向重复序列的形成，而反向重复序列在许多基因组中都大量存在。尽管这一过程的普遍性和普遍性，但人们对促进突变或采取行动避免突变的因素知之甚少。利用大肠杆菌Thya基因中的一个自然突变热点，该项目将确定控制模板切换突变的因素，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突变的基因提供了独特的机会。这一方法将为突变和突变避免的机制提供新的见解。其他实验试图阐明染色体背景或复制叉的损坏是否会影响此类事件的发生频率。本科生和研究生将进行拟议的实验，该实验室在本科生和研究生参与研究方面有着良好的记录。因此，该提案的更广泛影响是对学生进行最先进的基因分析培训，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.