NMR STUDIES OF MULV AND SECIS RNA DECODING STIMULATORS

对遗传密码的重新编码受到重定向和重新定义的影响 在特定位点的少量mRNAs中存在广泛的 有机体。终止密码子的重新定义可用于产生 更大的功能蛋白，或者插入特化的 氨基酸(即硒半胱氨酸)转化为蛋白质的特定点，以供 改变了物理属性。重新编码受控于信息 嵌入到信使核糖核酸中，信使核糖核酸以特定密码子和 信使核糖核酸(刺激物)中的结构区域。一种结构 对这些信使核糖核酸刺激物的理解将使我们对 重新定义事件的机制和对 翻译重新编码。两种信使核糖核酸的结构研究 提出了刺激要素的概念。(1)所需的刺激因素 在真核生物中插入的硒半胱氨酸位于3‘-非编码区和 由带有内环的干环结构组成。这个 顶端环中保守的核心区和腺苷的游程将 在这些保守的结构性质方面被核磁共振研究 各地区拥有。这将澄清两个提议的 次要模型，并将突出环路I在 将两个螺旋区域围绕核心区域对齐。(2) 伪结刺激元素被证明是UAG重新定义所必需的 在Maloney小鼠中，将对白血病病毒(MuLV)进行生物物理探索 调整目前由遗传方法产生的二级模型，以及 解释提议的LoopII和间隔区中的高度保守区域 地区。实验将在一名 UAG终止密码子上游的附加元件。竞争 因为伪结的形成将被监测，以及 重新定义的效率。与之交互的蜂窝组件 这两个元素中的一个/两个将在整个生命周期中寻求 这种逆转录病毒。这些信息将使我们能够生产小型机 寡核苷酸用于高分辨率研究这种假性结节 刺激器。

Recoding of the genetic code is subject to redirection and redefinition at specific sites in a small number of mRNAs for a wide range of organisms. Redefinition of termination codons can be used to produce larger functional proteins, or alternatively, to insert specialized amino acids (i.e. selenocysteine) into specific points of a protein for altered physical properties. Recoding is under control of information embedded within the mRNA, which is available as specific codons and structured regions in the mRNA (stimulators). A structural understanding of these mRNA stimulators will give insight to the overall mechanisms of redefinition events and a general understanding for translational recoding. A structural investigation of two mRNA stimulatory elements is proposed. (1) The stimulatory element required for selenocysteine insertion in eukaryotes is located in the 3'-UTR and is composed of a stem loop structure with an internal loop. The conserved core region and run of adenosines in the apical loop will be investigated by NMR in terms of structural properties these conserved regions possess. This will clarify discrepancies of two proposed secondary models, and will highlight the importance of loop I in aligning the two helical regions about the core region. (2) The pseudoknot stimulatory element shown to be required for UAG redefinition in Maloney Murine Leukemia Virus (MuLV) will be biophysically probed to tune up the current secondary model produced by genetic approaches, and to interpret highly conserved regions in the proposed loopII and spacer regions. Experiments will be conducted with the presence of a additional element upstream of the UAG termination codon. Competition for the formation of the pseudoknot will be monitored, as well as the efficiency of redefinition. Cellular components that interact with either/both of these elements will be sought through the life cycle of this retrovirus. This information will enable us to produce small model oligonucleotides for high-resolution studies of this pseudoknot stimulator.