Rat1p and Rai1p function with the nuclear exosome in the processing and degradation of rRNA precursors
Rat1p and Rai1p function with the nuclear exosome in the processing and degradation of rRNA precursors
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DOI：
10.1261/rna.2900205
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发表时间：
2005-10-01
期刊：
影响因子：
4.5
通讯作者：
Butler, JS
中科院分区：
文献类型：
--
作者：
Fang, F;Phillips, S;Butler, JS
核糖核酸外切酶在所有生物体中的各种RNA的加工和降解中起作用。这些酶在rRNA的成熟和在抑制核糖体生物合成后降解rRNA前体的质量控制途径中起着特别重要的作用。在RNA加工外泌体的3 '-5'外泌核糖核酸分解组分中具有缺陷的菌株积累多腺苷酸化前体rRNA，其也在具有核糖体生物发生缺陷的菌株中出现。这些发现表明，多聚腺苷酸化可能靶向前体rRNA，以便被外泌体降解。在这里，我们报告的实验表明，5 '-3'核糖核酸外切酶Rat 1 p及其相关蛋白Rail p在poly（A）（+）pre-rRNA降解中的作用。Rat 1 p的缺失增加了在缺失外泌体亚基Rrp 6p的菌株中积累的poly（A）（+）pre-rRNA的量，并降低了它们的5'异质性。RAI 1的缺失导致poly（A）（+）pre-rRNA的积累，并抑制Rat 1 p依赖的5 '-末端加工和Rrp 6p依赖的3'-末端加工5.8S rRNA。RAT 1和RAI 1突变在rrp 6-Delta存在下导致协同生长缺陷，这与5 '端和T端加工途径的相互依赖性一致。这些发现表明Rail p可能协调Rat 1 p和核外泌体的5 '端和3'端加工和降解活动。
Exoribonucleases function in the processing and degradation of a variety of RNAs in all organisms. These enzymes play a particularly important role in the maturation of rRNAs and in a quality-control pathway that degrades rRNA precursors upon inhibition of ribosome biogenesis. Strains with defects in 3'-5' exoribonucleolytic components of the RNA processing exosome accumulate polyadenylated precursor rRNAs that also arise in strains with ribosome biogenesis defects. These findings suggested that polyadenylation might target pre-rRNAs for degradation by the exosome. Here we report experiments that indicate a role for the 5'-3' exoribonuclease Rat1p and its associated protein Rail p in the degradation of poly(A)(+) pre-rRNAs. Depletion of Rat1p enhances the amount of poly(A)(+) pre-rRNA that accumulates in strains deleted for the exosome subunit Rrp6p and decreases their 5' heterogeneity. Deletion of RAI1 results in the accumulation of poly(A)(+) pre-rRNAs, and inhibits Rat1p-dependent 5'-end processing and Rrp6p-dependent 3'-end processing of 5.8S rRNA. RAT1 and RAI1 mutations cause synergistic growth defects in the presence of rrp6-Delta, consistent with the interdependence of 5'-end and T-end processing pathways. These findings suggest that Rail p may coordinate the 5'-end and 3'-end processing and degradation activities of Rat1p and the nuclear exosome.