Ty Element Retrotransposition in Saccharomyces cerevisia

酿酒酵母中的 Ty 元件逆转录转座

• 批准号: 7338477
• 负责人: David J. Garfinkel
• 金额: --
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7338477
• 关键词: Ty; Element; Retrotransposition; Saccharomyces; cerevisia

Over the past year, we have made progress in the following areas. Ty1 copy number dynamics has been studied by reintroducing active elements into a Ty-less strain where resident elements had been lost by long terminal repeat (LTR-LTR) recombination. Repopulated strains exhibit alterations in chromosome size that are associated with Ty1 insertions, but do not become genetically isolated. The rates of element gain and loss under genetic and environmental conditions known to affect Ty1 retrotransposition have been determined using genetically tagged reference elements. Ty1 gain and loss ratios obtained under different conditions suggest that copy number oscillates over time by altering the rate of retrotransposition, resulting in the diverse copy numbers observed in Saccharomyces. On a broader scale, our results suggest that the gain and loss of LTR-retrotransposons can be highly dynamic and has the potential to remodel genomes over short evolutionary time periods. In collaboration with Dr. Dwight V. Nissley (SAIC, Frederick MD), we have shown that hybrid elements composed of Ty1 and the reverse transcriptase gene from HIV-1 are useful tools for detecting, monitoring, and isolating drug-resistant reverse transcriptases in budding yeast. This sensitive phenotypic assay detects drug-resistant variants in clinical samples when the variants comprise as little as 0.3 to 1.0% of the virus population. Furthermore, our assay can detect of both known and novel reverse transcriptase variants and should be useful in studies of the evolution and clinical significance of minor drug-resistant variants.

过去一年，我们在以下方面取得了进展。Ty 1拷贝数动态已通过将活性元件重新引入无Ty-less菌株中进行了研究，其中常驻元件已通过长末端重复序列（LTR-LTR）重组而丢失。再繁殖的菌株表现出与Ty 1插入相关的染色体大小改变，但不会成为遗传隔离。已知影响Ty 1反转录转座的遗传和环境条件下的元件获得和损失的速率已经使用遗传标记的参考元件来确定。在不同条件下获得的Ty 1增益和损失比表明，拷贝数随着时间的推移通过改变反转录转座的速率而振荡，导致在酵母中观察到的不同拷贝数。在更广泛的范围内，我们的研究结果表明，LTR-反转录转座子的获得和损失可以是高度动态的，并有可能在短的进化时间内重塑基因组。在与德怀特V. Nissley博士（SAIC，Frederick MD）的合作中，我们已经证明了由Ty 1和HIV-1逆转录酶基因组成的杂交元件是检测、监测和分离芽殖酵母中耐药逆转录酶的有用工具。这种灵敏的表型检测试剂盒可检测临床样本中的耐药变异体，当变异体仅占病毒种群的0.3%至1.0%时。此外，我们的检测方法可以检测已知的和新的逆转录酶变异，并应在研究的演变和临床意义的轻微耐药变异。