Transcription-dependent nucleolar cap localization and possible nuclear function of DExH RNA helicase RHAU
Transcription-dependent nucleolar cap localization and possible nuclear function of DExH RNA helicase RHAU
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DOI：
10.1016/j.yexcr.2008.01.006
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发表时间：
2008-04-01
影响因子：
3.7
通讯作者：
Nagamine, Yoshikuni
中科院分区：
文献类型：
--
作者：
Iwamoto, Fumiko;Stadler, Michael;Nagamine, Yoshikuni
RHAU（RNA helicase associated with AU-rich element）是一种DExH蛋白，最初被鉴定为加速AU-rich elements介导的mRNA降解的因子。尽管mRNA降解发生在细胞质中，但RHAU主要定位于细胞核的发现促使我们考虑RHAU的核功能。在HeLa细胞中，发现RHAU定位于整个核质中，一些集中在核斑点中。转录停滞改变了核仁帽的定位，RHAU与RNA解旋酶p68和p72密切相关，表明RHAU参与了细胞核中转录相关的RNA代谢。为了了解RHAU是否在转录或转录后影响全局基因表达，我们使用来自RHAU耗尽的HeLa细胞系的总RNA进行微阵列分析，通过放线菌素D追踪测量稳态mRNA水平和mRNA半衰期。大多数转录本的半衰期没有变化，其稳态水平受到RHAU敲低的影响，这表明这些转录本受到转录调控。我们认为RHAU具有双重功能，参与不同亚细胞区室中mRNA的合成和降解。(C)2008年爱思唯尔公司All rights reserved.
RHAU (RNA helicase associated with AU-rich element) is a DExH protein originally identified as a factor accelerating AU-rich element-mediated mRNA degradation. The discovery that RHAU is predominantly localized in the nucleus, despite mRNA degradation occurring in the cytoplasm, prompted us to consider the nuclear functions of RHAU. In HeLa cells, RHAU was found to be localized throughout the nucleoplasm with some concentrated in nuclear speckles. Transcriptional arrest altered the localization to nucleolar caps, where RHAU is closely localized with RNA helicases p68 and p72, suggesting that RHAU is involved in transcription-related RNA metabolism in the nucleus. To see whether RHAU affects global gene expression transcriptionally or posttranscriptionally, we performed microarray analysis using total RNA from RHAU-depleted HeLa cell lines, measuring both steady-state mRNA levels and mRNA half-lives by actinomycin D chase. There was no change in the half-lives of most transcripts whose steady-state levels were affected by RHAU knockdown, suggesting that these transcripts are subjected to transcriptional regulation. We propose that RHAU has a dual function, being involved in both the synthesis and degradation of mRNA in different subcellular compartments. (C) 2008 Elsevier Inc. All rights reserved.