Causes and consequences of Blm-dependent DNA replication challenges

保持基因组DNA的完整性对细胞的功能和生存至关重要。蛋白质，如 Bloom(BLM)DNA解旋酶保护基因组免受两者的有害影响 DNA损伤的外源性和内源性来源。人类体内BLM活性的丧失导致 以发育为特征的罕见常染色体隐性遗传病Bloom综合征 异常、过早衰老和癌症易感性。这项拟议研究的目标是 研究BLM在防止与重复DNA相关的DNA损伤中所起的作用 序列。由于人黑腹果蝇和黑腹果蝇之间的功能保守 BLM蛋白，我们建议用果蝇作为研究BLM依赖的复制的模型 重复DNA序列带来的挑战。依赖重复的细胞后果 BLM的复制挑战仍然未知，但果蝇胚胎为我们提供了有用的 用于研究BLM函数的这些方面的模型。我们之前的数据表明，BLM促进了 在早期复制重复的DNA序列，特别是高度重复的Y染色体 胚胎发育。我们建议鉴定Y染色体上的重复序列 提出BLM依赖的复制挑战，并调查BLM缺乏的长期影响 在早期发育过程中。我们将在目标1中通过利用 果蝇Y-连锁重复DNA序列用于确定特定的BLM依赖序列基序 在Y染色体上。为此，我们将筛选显示Y链接的、依赖于BLm的线 然后分析这些品系的全基因组序列，寻找Y染色体的差异 重复的DNA含量。在胚胎发育过程中缺乏BLm的长期生物学效应将是 在目标2中，通过比较有或没有母体发育的BLM杂合子果蝇来进行调查 BLM用于可能受到亚致死量DNA损伤影响的各种表型。那些 表型包括寿命、生育能力、身体成分和运动能力。最后，在路线方面 根据SURE计划的目标，这笔赠款的目标3将提供高影响力的密集 浅谈生物医学专业本科生的本科科研培养 研究。这项建议将为学生提供直接参与执行、分析和 报告这项研究，并将支持LC State作为一个充满活力的机构的日益增长的声誉 来自不同背景的未来生物医学科学家和医疗保健专业人员。

Maintaining the integrity of genomic DNA is crucial to cellular function and survival. Proteins such as Bloom (BLM) DNA helicase function to protect the genome from the deleterious effects of both exogenous and endogenous sources of DNA damage. Loss of BLM activity in humans leads to the rare autosomal recessive disorder Bloom Syndrome, which is characterized by developmental abnormalities, premature aging, and cancer susceptibility. The goal of this proposed research is to investigate the role that BLM plays in preventing DNA damage associated with repetitive DNA sequences. Due to the functional conservation between human BLM and Drosophila melanogaster Blm proteins, we propose to use Drosophila as a model for studying the Blm-dependent replication challenges posed by repetitive DNA sequences. The cellular consequences of repeat-dependent replication challenges to Blm remain unknown, but the Drosophila embryo provides us with a useful model for studying these aspects of Blm function. Our previous data suggest that Blm facilitates replication of repetitive DNA sequences, particularly the highly repetitive Y chromosome, during early embryo development. We propose to identify the repetitive sequences on the Y chromosome that pose Blm-dependent replication challenges and to investigate long-term effects of Blm-deficiency during early development. We will address these questions in Aim 1 by exploiting natural variation in Y-linked repetitive DNA sequences in Drosophila to define specific Blm-dependent sequence motifs on Y chromosomes. To accomplish this, we will screen for lines displaying Y-linked, Blm-dependent variation and then analyze whole genome sequences of these lines for differences in Y chromosome repetitive DNA content. Long-term biological effects of Blm-deficiency during embryogenesis will be investigated in Aim 2 by comparing Blm heterozygous flies that developed with or without maternal Blm for a variety of phenotypes that might be affected by sub-lethal amounts of DNA damage. Those phenotypes will include lifespan, fertility, body composition, and locomotor activity. Lastly, in alignment with the goals of the SuRE program, Aim 3 of this grant will provide high-impact intensive undergraduate research training of undergraduate students who are underrepresented in biomedical research. This proposal will provide students with direct participation in the execution, analysis, and reporting of this research and will support the growing reputation of LC State as a vibrant institution for future biomedical scientists and healthcare professionals that come from diverse backgrounds.