Department of Biochemistry, University of São Paulo, São Paulo, SP, Brazil.
FEBS J. 2010 Jul;277(13):2838-52. doi: 10.1111/j.1742-4658.2010.07701.x. Epub 2010 May 27.
In eukaryotes, pre-rRNA processing depends on a large number of nonribosomal trans-acting factors that form intriguingly organized complexes. Two intermediate complexes, pre-40S and pre-60S, are formed at the early stages of 35S pre-rRNA processing and give rise to the mature ribosome subunits. Each of these complexes contains specific pre-rRNAs, some ribosomal proteins and processing factors. The novel yeast protein Utp25p has previously been identified in the nucleolus, an indication that this protein could be involved in ribosome biogenesis. Here we show that Utp25p interacts with the SSU processome proteins Sas10p and Mpp10p, and affects 18S rRNA maturation. Depletion of Utp25p leads to accumulation of the pre-rRNA 35S and the aberrant rRNA 23S, and to a severe reduction in 40S ribosomal subunit levels. Our results indicate that Utp25p is a novel SSU processome subunit involved in pre-40S maturation.
在真核生物中，前 rRNA 加工依赖于大量非核糖体反式作用因子，这些因子形成了引人入胜的组织复杂结构。两个中间复合物，前 40S 和前 60S，在前 35S 前 rRNA 加工的早期形成，并产生成熟的核糖体亚基。这些复合物中的每一个都包含特定的前 rRNA、一些核糖体蛋白和加工因子。先前在核仁中鉴定出新型酵母蛋白 Utp25p，表明该蛋白可能参与核糖体生物发生。在这里，我们表明 Utp25p 与 SSU 加工体蛋白 Sas10p 和 Mpp10p 相互作用，并影响 18S rRNA 的成熟。Utp25p 的缺失会导致前 rRNA 35S 和异常 rRNA 23S 的积累，并导致 40S 核糖体亚基水平严重降低。我们的结果表明，Utp25p 是一种新的 SSU 加工体亚基，参与前 40S 成熟。
