外泌体亚基Rrp43p是5.8S、18S和25S核糖体RNA高效成熟所必需的。
The exosome subunit Rrp43p is required for the efficient maturation of 5.8S, 18S and 25S rRNA.
作者信息
Zanchin N I, Goldfarb D S
机构信息
Department of Biology, University of Rochester, Rochester, NY 14627, USA.
出版信息
Nucleic Acids Res. 1999 Mar 1;27(5):1283-8. doi: 10.1093/nar/27.5.1283.
The Saccharomyces cerevisiae protein Rrp43p co-purifies with four other 3'-->5' exoribonucleases in a complex that has been termed the exosome. Rrp43p itself is similar to prokaryotic RNase PH. Individual exosome subunits have been implicated in the 3' maturation of the 5.8S rRNA found in 60S ribosomes and the 3' degradation of mRNAs. However, instead of being deficient in 60S ribosomes, Rrp43p-depleted cells were deficient in 40S ribosomes. Pulse-chase and steady-state northern analyses of pre-RNA and rRNA levels revealed a significant delay in the synthesis of both 25S and 18S rRNAs, accompanied by the stable accumulation of 35S and 27S pre-rRNAs and the under-accumulation of 20S pre-rRNA. In addition, Rrp43p-depleted cells accumulated a 23S aberrant pre-rRNA and a fragment excised from the 5' ETS. Therefore, in addition to the maturation of 5.8S rRNA, Rrp43p is required for the maturation 18S and 25S rRNA.
酿酒酵母蛋白Rrp43p与其他四种3'→5'外切核糖核酸酶共纯化，形成一个被称为外切体的复合物。Rrp43p本身类似于原核核糖核酸酶PH。单个外切体亚基与60S核糖体中5.8S rRNA的3'端成熟以及mRNA的3'端降解有关。然而，Rrp43p缺失的细胞并非缺乏60S核糖体，而是缺乏40S核糖体。对前体RNA和rRNA水平进行脉冲追踪和稳态Northern分析发现，25S和18S rRNA的合成均显著延迟，同时35S和27S前体rRNA稳定积累，而20S前体rRNA积累不足。此外，Rrp43p缺失的细胞积累了一种23S异常前体rRNA和一个从5'ETS切除的片段。因此，除了5.8S rRNA的成熟外，18S和25S rRNA的成熟也需要Rrp43p。
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