The DEAD-box RNA helicase-like Utp25 is an SSU processome component
The DEAD-box RNA helicase-like Utp25 is an SSU processome component
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DOI：
10.1261/rna.2359810
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发表时间：
2010-11-01
期刊：
影响因子：
4.5
通讯作者：
Baserga, Susan J.
中科院分区：
文献类型：
--
作者：
Charette, J. Michael;Baserga, Susan J.
SSU加工体是由U3 snoRNA和至少43种蛋白质组成的大型核糖核蛋白复合物。一个数据库搜索，开始在努力发现额外的SSU加工组成分，确定了未表征的，保守的和必要的酵母核仁蛋白YIL 091 C/UTP 25作为这样的候选人。C-末端DUF 1253基序是一个未知功能的结构域，与DEAD盒RNA解旋酶的序列相似性有限。在缺乏保守的DEAD盒序列的情况下，基序Ia是唯一可清楚识别的解旋酶元件。由于酵母同源物是核仁和相互作用的SSU加工体的组成部分，我们研究了它在前rRNA加工的作用。Utp 25的基因缺失导致生长减缓。前体rRNA的北方分析显示在位点A（0）、A（1）和A（2）处存在18 S rRNA成熟缺陷。免疫共沉淀证实了与U3 snoRNA和Mpp 10的关联，以及与t-Utp/UtpA、UtpB和U3 snoRNP亚复合物的组分的关联。保守基序Ia残基的突变导致没有可辨别的温度敏感性或冷敏感性生长缺陷，这意味着该基序是Utp 25功能的抑制剂。Utp 25对其他SSU加工组成分的酵母双杂交筛选揭示了几种相互作用的蛋白质，包括Mpp 10，Utp 3和Utp 21，从而确定了SSU加工组的不同亚复合物之间的第一次相互作用。此外，DUF 1253结构域对于Utp 25与Utp 3的相互作用是必需的并且是足够的。因此，Utp 25是一种新的SSU加工组成分，其沿着Utp 3，形成不同SSU加工组子复合体之间的第一个鉴定的相互作用。
The SSU processome is a large ribonucleoprotein complex consisting of the U3 snoRNA and at least 43 proteins. A database search, initiated in an effort to discover additional SSU processome components, identified the uncharacterized, conserved and essential yeast nucleolar protein YIL091C/UTP25 as one such candidate. The C-terminal DUF1253 motif, a domain of unknown function, displays limited sequence similarity to DEAD-box RNA helicases. In the absence of the conserved DEAD-box sequence, motif Ia is the only clearly identifiable helicase element. Since the yeast homolog is nucleolar and interacts with components of the SSU processome, we examined its role in pre-rRNA processing. Genetic depletion of Utp25 resulted in slowed growth. Northern analysis of pre-rRNA revealed an 18S rRNA maturation defect at sites A(0), A(1), and A(2). Coimmunoprecipitation confirmed association with U3 snoRNA and with Mpp10, and with components of the t-Utp/UtpA, UtpB, and U3 snoRNP subcomplexes. Mutation of the conserved motif Ia residues resulted in no discernable temperature-sensitive or cold-sensitive growth defects, implying that this motif is dispensable for Utp25 function. A yeast two-hybrid screen of Utp25 against other SSU processome components revealed several interacting proteins, including Mpp10, Utp3, and Utp21, thereby identifying the first interactions among the different subcomplexes of the SSU processome. Furthermore, the DUF1253 domain is required and sufficient for the interaction of Utp25 with Utp3. Thus, Utp25 is a novel SSU processome component that, along with Utp3, forms the first identified interactions among the different SSU processome subcomplexes.