GENETICS AND BIOCHEMISTRY OF RIBOSOME BIOSYNTHESIS

核糖体，蛋白质合成所必需的细胞器， 在细胞生长及其调节中起关键作用。 在细菌中， 细胞中核糖体的数量与生长速度成正比 在各种培养条件下（除了在 增长缓慢）。 每个核糖体蛋白质合成的平均速率 快速和缓慢生长的细胞是相同的，但存在更多的 丰富培养基中的核糖体允许产生更多的蛋白质， 整体增长率的提高。 我们的目标是了解 细菌调节核糖体的产生及其生长速率。 具体来说，我们最近的努力集中在基因的识别上， 核糖体蛋白和rRNA的研究，以及对核糖体蛋白和rRNA的调节的研究。 这些重要基因的表达。 我们最近发现， 核糖体蛋白质合成和核糖体装配是偶联的， 当核糖体蛋白质合成超过核糖体生物合成的速率时 某些关键的核糖体蛋白质作为抑制剂， 翻译自己的mRNA。 该反馈调节模型可以解释 协调和平衡地合成所有的核糖体蛋白 件. 我们会继续研究有关的详细机制， 核糖体蛋白质合成的翻译反馈调节。 在 此外，我们将研究核糖体的可能的转录调控， 蛋白质基因表达可能作为一个重要的调节 在某些其他条件下的机制，例如，在严格的控制下。 最后，我们将研究体内和体外转录调控 rRNA基因的表达，这是我们理解全球 调节生长细胞中核糖体的积累。

The ribosome, the organelle essential for protein synthesis, obviously plays a key role in cell growth and its regulation. In bacteria, the number of ribosomes in a cell is directly proportional to the growth rate of the cells under various culture conditions (except under conditions of very slow growth). The average rate of protein synthesis per ribosome in rapidly and slowly growing cells is the same, but the presence of more ribosomes in rich media permits more protein to be made and thus accounts for an overall increase in growth rate. Our goal is to understand how bacteria regulate the production of ribosomes and their growth rate. Specifically, our recent effort has focused on the identification of genes for ribosomal proteins and rRNA, and studies of the regulation of the expression of these important genes. We have recently discovered that ribosomal protein synthesis and ribosome assembly are coupled such that when ribosomal protein synthesis exceeds the rate of ribosome biosynthesis certain key ribosomal proteins act as inhibitors that prevent the further translation of their own mRNA. This feedback regulation model can account for coordinate and balanced synthesis of all of the ribosomal protein components. We will continue to study detailed mechanisms involved in the translational feedback regulation of ribosomal protein synthesis. In addition, we will study possible transcriptional regulation of ribosomal protein gene expression that might be operating as an important regulatory mechanism under some other conditions, e.g., during stringent control. Finally, we will study both in vivo and in vitro transcriptional regulation of rRNA gene expression which is fundamental to our understandig global regulation of ribosome accumulation in growing cells.