Causes and consequences of Blm-dependent DNA replication challenges

保持基因组DNA的完整性对细胞功能和生存至关重要。蛋白如 Bloom（BLM）DNA解旋酶的功能是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。人体BLM活性的丧失导致 罕见的常染色体隐性遗传疾病布卢姆综合征，其特征是发育 异常，过早衰老和癌症易感性。这项研究的目的是 研究BLM在预防与重复DNA相关的DNA损伤中的作用 序列的由于人BLM和果蝇BLM在功能上的保守性， Blm蛋白，我们建议使用果蝇作为研究Blm依赖性复制的模型 重复DNA序列带来的挑战。重复依赖的细胞后果 Blm的复制挑战仍然未知，但果蝇胚胎为我们提供了一个有用的 模型研究这些方面的BLM功能。我们以前的数据表明，Blm促进 在早期，重复DNA序列的复制，特别是高度重复的Y染色体， 胚胎发育我们建议识别Y染色体上的重复序列， 提出了BLM依赖的复制挑战，并调查BLM缺乏的长期影响 在早期发展中。我们将在目标1中通过利用自然变异来解决这些问题， 果蝇中Y-连锁重复DNA序列用于确定特定的Blm依赖性序列基序 在Y染色体上。为了实现这一点，我们将筛选显示Y连接、BLM相关的线 变异，然后分析这些品系的全基因组序列，以确定Y染色体的差异， 重复DNA含量在胚胎发生过程中BLM缺乏的长期生物学效应将是 在目标2中通过比较在有或没有母体的情况下发育的Blm杂合果蝇来研究 BLM用于可能受亚致死量DNA损伤影响的各种表型。那些 表型将包括寿命、生育力、身体组成和运动活动。最后，在调整 根据SuRE计划的目标，该赠款的目标3将提供高影响密集型 本科生研究培训的本科生谁是在生物医学代表性不足 research.该提案将为学生提供直接参与执行，分析， 报告这项研究，并将支持LC State作为一个充满活力的机构日益增长的声誉， 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.