Antisense RNAs control retrotransposon copy number

描述（由申请人提供）：反义RNA控制逆转录转座子拷贝数酿酒酵母的逆转录病毒样转座子Ty 1是理解HIV（AIDS的病原体）复制的有效模型，并且可以说是最好理解的逆转录转座子。反转录转座子通过RNA中间体复制，并已定殖于大多数真核生物基因组。研究Ty 1还提供了关于人类基因组动态和进化以及转座子诱导突变行为的有价值的信息。RNA干扰（RNAi）是一种广泛使用的机制，用于沉默感染性病毒和转座因子，并改变基因表达，其中小序列特异性RNA和保守的细胞蛋白影响转录，降解mRNA转录物或抑制翻译。有趣的是，S。酿酒酵母及其近亲缺乏RNAi所需的基因，但对Ty 1逆转录转座保持严格控制。我们发现了一个拷贝数控制（CNC）系统的基础上Ty 1反义（AS）RNA，抑制反转录转座后。非编码转录物被包装到病毒样颗粒中，并通过大大降低保守的Ty 1蛋白整合酶的水平来阻断逆转录，所述整合酶是Ty 1以及HIV-1逆转录和整合所需的。我们的目标是通过1）确定Ty 1AS转录物如何抑制反转录转座，2）鉴定介导Ty 1AS RNA合成，病毒样颗粒内包装和活性的序列结构域，以及3）表征影响AS转录物合成和功能的细胞基因来了解这种新型RNAi的机制。 我们预计这项研究将影响生物医学研究的两个领域。首先，了解Ty 1 CNC可用于帮助阐明HIV非编码RNA的功能，改进基于RNA的疗法，并确定药物开发的新靶点。其次，我们的工作将为研究非编码RNA如何在更广泛的范围内影响人类基因表达提供信息，特别是当人们认为超过90%的基因组被转录时，但这些转录本的功能却知之甚少。

DESCRIPTION (provided by applicant): Antisense RNAs control retrotransposon copy number The retrovirus-like transposon Ty1 of Saccharomyces cerevisiae is an effective model for understanding the replication of HIV, the causative agent of AIDS, and is arguably the best understood retrotransposon. Retrotransposons replicate through an RNA intermediate and have colonized most eukaryotic genomes. Studying Ty1 has also provided valuable information on human genome dynamics and evolution, and the behavior of transposon-induced mutations. RNA interference (RNAi) is a widespread mechanism used to silence infectious viruses and transposable elements, and alter gene expression, where small sequence-specific RNAs and conserved cellular proteins affect transcription, degrade mRNA transcripts or inhibit translation. Interestingly, S. cerevisiae and its closest relatives lack the genes required for RNAi, yet maintain tight control over Ty1 retrotransposition. We discovered a copy number control (CNC) system based on Ty1 antisense (AS) RNAs that inhibits retrotransposition posttranslationally. The noncoding transcripts are packaged into virus- like particles and block reverse transcription by greatly decreasing the level of the conserved Ty1 protein integrase, which is required for Ty1 as well as HIV-1 reverse transcription and integration. Our goal is to understand the mechanism of this novel form of RNAi by 1) determining how Ty1AS transcripts inhibit retrotransposition, 2) identifying sequence domains that mediate Ty1AS RNA synthesis, packaging and activity within virus-like particles, and 3) characterizing cellular genes that influence AS transcript synthesis and function. We expect this study to impact two areas of biomedical research. First, understanding Ty1 CNC can be used to help elucidate the function of HIV noncoding RNAs, improve RNA-based therapies, and identify new targets for drug development. Second, our work will inform research addressing how noncoding RNAs impact human gene expression on a broader scale, especially when one considers that over 90% of the genome is transcribed, yet the function of many of these transcripts is poorly understood.