RIBOSOMAL RNA SEQUENCE ANALYSIS

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 细胞生长和蛋白质合成的失控是癌症形成的一种新机制。与癌症易感性增加相关的越来越多的人类综合征的特征是调节核糖体功能的因素的基因突变。一个最好的例子是X-连锁先天性角化不良(X-DC)，其中编码假性尿苷合成酶的DKC1基因被发现突变。DKC1在核糖核蛋白复合体中发挥作用，与盒H/ACA小核仁RNA结合，指导rRNA位点特异性地将尿苷转化为假尿苷，这对核糖体的功能很重要。然而，它们在调节翻译控制中的具体作用以及它们在人类疾病中的影响却知之甚少。 我们的实验室先前已经在X-DC和人类X-DC患者细胞的小鼠模型中证明，DKC1的突变极大地降低了rRNA假尿酸的全球水平，改变了对特定mRNAs的翻译控制，这些mRNAs通过一种独特的机制被称为IRES(内部核糖体进入位点)介导的翻译。在细胞周期和细胞存活等不同的细胞事件中，这种翻译启动模式对于调节包括肿瘤抑制基因在内的关键mRNAs的表达是重要的。我们假设，受损的特定伪尿嘧啶残基簇的rRNA假性连接直接影响核糖体参与IRES介导的特定mRNAs翻译启动的能力，从而导致与X-DC相关的病理特征。本研究的目的是研究DKC1催化的rRNA上的哪些假尿苷残基是IRES介导的有效翻译所必需的。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Deregulation in cell growth and protein synthesis is an emerging mechanism for cancer formation. A growing list of human syndromes associated with increased cancer susceptibility is characterized by genetic mutations in factors regulating ribosome function. One the best examples is X-linked Dyskeratosis Congenita (X-DC), where the DKC1 gene, encoding for the pseudouridine synthase that modifies rRNA, is found mutated. DKC1 functions within ribonucleoprotein complexes in combination with the box H/ACA small nucleolar RNAs that guide the rRNA site-specific conversion of uridines to pseudouridines, important for the function of the ribosome. However, their specific role in modulating translational control and their impact in human disease is poorly understood. Our laboratory has previously demonstrated, in both a mouse model for X-DC and human X-DC patient cells, that mutations in DKC1 greatly decrease global levels of rRNA pseudouridylation altering translational control of specific mRNAs, which are translated through a distinct mechanism known as IRES (Internal ribosome entry site)-mediated translation. This mode of translation initiation is important to regulate the expression of key mRNAs, including tumor suppressor genes, during distinct cellular events such as cell cycle and cell survival. We hypothesize that impaired rRNA pseudouridylation of specific clusters of pseudouridine residues directly impinge on the ability of the ribosome to engage in IRES-mediated translation initiation of specific mRNAs leading to the pathological features associated with X-DC. The goal of this study is to investigate which pseudouridine residues on the rRNA, catalyzed by DKC1, are required for efficient IRES-mediated translation.