MINORITY PREDOCTORAL FELLOWSHIP PROGRAM

描述（由申请人提供）：假尿嘧啶是尿嘧啶的5-核糖基异构体，是RNA分子中已知的最常见的转录后修饰。模型大肠杆菌的核糖体含有11个假尿嘧啶；10个在23S RNA中，1个在16S RNA中。这些假尿嘧啶是由7个位点特异性的假尿嘧啶合成酶形成的，没有重叠特异性。删除任何一个合成酶基因的效果是失去它形成的假尿嘧啶(s)。到目前为止，还没有发现假尿嘧啶特异性生长缺陷。我们计划制造一个携带4个合成酶基因缺失和6个假尿嘧啶缺失的菌株，以研究这些假尿嘧啶缺失核糖体与正常核糖体在结构和/或功能上的差异。这些差异可能有助于深入了解假尿嘧啶在核糖体中的功能。此外，我们计划绘制假尿嘧啶在耐辐射球菌核糖体中的位置，因为其50S核糖体亚基的晶体结构是可用的，我们可以在3D空间中模拟假尿嘧啶的位置，从而可能基于结构了解功能。在核糖体中，假尿嘧啶倾向于聚集在肽基转移酶中心周围，这可能暗示了翻译的结构和/或功能作用-这对所有生物体的健康至关重要。如果假尿嘧啶确实参与了翻译，那么我们可能有一个新的抗生素靶点，因为人类核糖体假尿嘧啶的形成机制与细菌不同。

DESCRIPTION (provided by applicant): Pseudouridine, the 5-ribosyl isomer of uridine, is the most common post-transcriptional modification known in RNA molecules. The ribosome of the model eubacterum Escherichia coli has eleven pseudouridines; 10 in the 23S RNA and 1 in the 16S RNA. These pseudouridines are formed by 7 site-specific pseudouridine synthases with no overlapping specificity. The effect of deleting any one synthase gene is loss of the pseudouridine(s) that it forms. Thus far, no pseudouridine specific growth defect has been detected. We plan to make a strain carrying 4 synthase gene deletions and lacking 6 pseudouridines to investigate the structural and/or functional differences of these pseudouridine deficient ribosomes from normal ribosomes. These differences may provide insight into the function of pseudouridine in the ribosome. In addition, we plan to map the positions of pseudouridien in the ribosome of deinococcus radiodurans because the cyrstal structure of its 50S ribosomal subunit is available and we can model the positions of pseudouridines in 3D space for possible insights into function based on structure. In ribosomes, pseudouridines tend to cluster around the peptidyl transferase center which may implicate a structural and/or functional role in translation - which is crucial to the well-being of all organisms. If pseudouridines do participate in translation, then we may have a new antibiotic target because the mechanism of ribosomal pseudouridine formation in humans differs from that of bacteria.