Department of Biological Sciences, Center for Nucleic Acids Science and Technology, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213.
Genetics. 2013 Nov;195(3):643-81. doi: 10.1534/genetics.113.153197.
Ribosomes are highly conserved ribonucleoprotein nanomachines that translate information in the genome to create the proteome in all cells. In yeast these complex particles contain four RNAs (>5400 nucleotides) and 79 different proteins. During the past 25 years, studies in yeast have led the way to understanding how these molecules are assembled into ribosomes in vivo. Assembly begins with transcription of ribosomal RNA in the nucleolus, where the RNA then undergoes complex pathways of folding, coupled with nucleotide modification, removal of spacer sequences, and binding to ribosomal proteins. More than 200 assembly factors and 76 small nucleolar RNAs transiently associate with assembling ribosomes, to enable their accurate and efficient construction. Following export of preribosomes from the nucleus to the cytoplasm, they undergo final stages of maturation before entering the pool of functioning ribosomes. Elaborate mechanisms exist to monitor the formation of correct structural and functional neighborhoods within ribosomes and to destroy preribosomes that fail to assemble properly. Studies of yeast ribosome biogenesis provide useful models for ribosomopathies, diseases in humans that result from failure to properly assemble ribosomes.
核糖体是高度保守的核糖核蛋白纳米机器，可将基因组中的信息翻译成所有细胞中的蛋白质组。在酵母中，这些复杂的颗粒包含四种 RNA（>5400 个核苷酸）和 79 种不同的蛋白质。在过去的 25 年中，酵母的研究为理解这些分子如何在体内组装成核糖体奠定了基础。组装始于核仁中核糖体 RNA 的转录，然后 RNA 经历复杂的折叠途径，同时进行核苷酸修饰、间隔序列去除和与核糖体蛋白结合。超过 200 种组装因子和 76 种小核仁 RNA 与正在组装的核糖体短暂结合，以实现其准确和高效的构建。前核糖体从细胞核输出到细胞质后，在进入功能核糖体池之前，它们经历最后的成熟阶段。存在复杂的机制来监测核糖体内正确结构和功能邻里的形成，并破坏未能正确组装的前核糖体。酵母核糖体生物发生的研究为核糖体病（ribosomopathies）提供了有用的模型，核糖体病是人类因核糖体组装不正确而导致的疾病。
