Role of the Obg proteins in Saccharomyces cerevisiae

细胞中的所有蛋白质都是通过核糖体的活动合成的。 核糖体由大小核糖体亚基（分别为60 S和40 S）组成。 在酵母中，成熟的60 S核糖体亚基含有46个蛋白质和3个rRNA，而成熟的40 S核糖体亚基含有32个蛋白质和1个rRNA。这些核糖体颗粒的组装通过一系列有序的复合物发生，因为添加了额外的核糖体蛋白，并且rRNA被切割和修饰。 在整个过程中，非核糖体蛋白质有助于必要的修饰和构象变化。 导致成熟rRNA的加工和修饰事件相对较好地理解。 然而，相比之下，导致rRNA与核糖体蛋白组装的事件却知之甚少。 对于核糖体组装至关重要的是GTP结合蛋白Nog 1 p的功能。Nog 1 p对于60 S亚基组装是必不可少的，并且Nog 1 p的GTP水解可能是前60 S核糖体亚基的关键重塑步骤所必需的。这项研究的重点是表征Nog 1 p及其在60 S组装中的作用。特别是，Nog 1 p的GTP结合和水解特性将被确定，以预测它如何在细胞中发挥作用。 此外，Nog 1 p和前60 S核糖体亚基之间的关系将使用各种遗传和生物化学方法进行研究。 最后，与Nog 1 p相互作用的蛋白质和/或rRNA将被鉴定和表征，从而阐明它们之间的关系。 这些研究将使我们更好地理解细胞如何协调大型复杂的蛋白质-RNA复合物的时间组装。

All proteins in the cell are synthesized by the activity of ribosomes. Ribosomes are composed of large and small ribosomal subunits (60S and 40S, respectively). In the yeast, the mature 60S ribosomal subunit contains 46 proteins and three rRNAs while the mature 40S ribosomal subunit contains 32 proteins and the one rRNA. The assembly of these ribosomal particles occurs via an ordered series of complexes as additional ribosomal proteins are added, and rRNA is cleaved and modified. Throughout this process, non-ribosomal proteins aid in requisite modifications and conformational changes. The processing and modification events leading to the mature rRNAs are relatively well understood. In contrast, however, the events that lead to the assembly of the rRNAs with the ribosomal proteins are poorly understood. Critical to ribosome assembly is the function of a GTP-binding protein, Nog1p. Nog1p is essential for 60S subunit assembly and it is likely that GTP hydrolysis by Nog1p is required for a critical remodeling step of the pre-60S ribosomal subunit. This research focuses on characterizing Nog1p and its role in 60S assembly. In particular, the GTP binding and hydrolysis characteristics of Nog1p will be determined in order to predict how it may function in the cell. Further, the relationship between Nog1p and the pre-60S ribosomal subunits will be investigated using a variety of genetic and biochemical approaches. Finally, the proteins and/or rRNA that interact with Nog1p will be identified and characterized such that their relationships will be elucidated. These studies will result in a greater understanding of how the cell orchestrates the temporal assembly of a large and complicated protein-RNA complex.