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Type: Journal article
Title: mTOR signaling regulates the processing of pre-rRNA in human cells
Author: Iadevaia, V.
Zhang, Z.
Jan, E.
Proud, C.
Citation: Nucleic Acids Research, 2012; 40(6):2527-2539
Publisher: Oxford University Press (OUP)
Issue Date: 2012
ISSN: 0305-1048
Statement of
Valentina Iadevaia, Ze Zhang, Eric Jan, and Christopher G. Proud
Abstract: Signaling through the mammalian target of rapamycin, complex 1 (mTORC1), positively regulates the transcription of ribosomal RNA (rRNA) and the synthesis of ribosomal proteins, thereby promoting the complex process of ribosome biogenesis. The major rRNAs are transcribed as a single precursor, which must be processed to create the 5.8S, 18S and 28S rRNAs. We used a new non-radioactive labeling approach to study the effects of rapamycin, an inhibitor of mTORC1, on rRNA synthesis. Rapamycin not only impaired synthesis of new 18S, 28S or 5S rRNA but also induced their decay. This prompted us to examine the effects of rapamycin on rRNA processing. We show that rapamycin also interferes with the processing events that generate 18S and 28S rRNA. rRNA transcription and processing occur in regions of the nucleus known as nucleoli. We find that the mTORC1 components raptor and mTOR are both present in nucleoli, where they may regulate rRNA maturation events. While rapamycin has no effect on overall nucleolar morphology or its proteome, it does induce loss of mTOR and raptor from them. These data show that mTORC1 is located in nucleoli where it acts to regulate events involved in ribosome biogenesis including the maturation of rRNA molecules.
Keywords: Hela Cells; Cell Nucleolus; Humans; Sirolimus; Multiprotein Complexes; Proteins; Ribosomal Proteins; RNA Precursors; RNA, Ribosomal; Signal Transduction; Protein Biosynthesis; RNA Processing, Post-Transcriptional; RNA Stability; TOR Serine-Threonine Kinases; Mechanistic Target of Rapamycin Complex 1
Rights: © The Author(s) 2011. Published by Oxford University Press. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( by-nc/3.0), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
RMID: 0020128141
DOI: 10.1093/nar/gkr1040
Appears in Collections:Molecular and Biomedical Science publications

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