Nobel regulatory mechanism for transcription of genes encoding ribosomal components in S. cerevisiae

本研究对HMGB家族成员Hmo1蛋白在大肠杆菌中的功能进行了研究。酿酒。Hmo1与35S核糖体RNA基因和核糖体蛋白基因启动子结合，它们分别由Pol I和Pol II转录，并协同调节这些基因的转录以响应环境条件。从使用各种HMO1突变株和蛋白质的分析中，我们阐明了HMO1通过盒A二聚化（或多聚化），其功能尚不清楚，并以这种形式与靶DNA结合。此外，基于HMO 1基因的缺失与编码S.酿酒酵母，导致严重的生长缺陷，我们进行了遗传分析，以澄清这种双重破坏剂的生长缺陷的原因。结果表明，这些蛋白质在Pol I启动rRNA转录的起始步骤中协同工作。

In this study, we conducted a research for the function of Hmo1 protein, a member of HMGB family proteins in S. cerevisiae. Hmo1 binds to the 35S ribosomal RNA gene and ribosomal protein gene promoters, which are transcribed by Pol I and Pol II, respectively, and regulates transcription of these genes cooperatively in response to environmental conditions. From analyses using various HMO1 mutant strains and proteins, we elucidated that Hmo1 dimerizes (or multimerizes) through box A, of which function has been unknown, and binds to target DNA in this form. In addition, based on the observation that deletion of HMO1 gene, in combination with deletion of FPR1 gene that encodes one of PPIase (peptidylprolyl isomerase) in S. cerevisiae, causes severe growth defect, we conducted genetic analyses to clarify the cause of a growth defect of this double disruptant. As the result, we revealed that these proteins work cooperatively at the step of initiation in transcription of rRNA by Pol I.