Overexpression of HuR, a nuclear-cytoplasmic shuttling protein, increases the in vivo stability of ARE-containing mRNAs

The messenger RNAs of many proto‐oncogenes, cytokines and lymphokines are targeted for rapid degradation through AU‐rich elements (AREs) located in their 3′ untranslated regions (UTRs). HuR, a ubiquitously expressed member of the Elav family of RNA binding proteins, exhibits specific affinities for...

Full description

Saved in:
Bibliographic Details
Published in:The EMBO journal 1998-06, Vol.17 (12), p.3448-3460
Main Authors: Fan, Xinhao Cynthia, Steitz, Joan A.
Format: Article
Language:English
Subjects:
Animals
Antigens, Surface
ARE
Cell Nucleus - metabolism
Cells, Cultured
Cytoplasm - metabolism
ELAV Proteins
ELAV-Like Protein 1
HeLa Cells
Humans
HuR
Mice
mRNA decay
nuclear-cytoplasmic shuttling protein
RNA, Messenger - metabolism
RNA-Binding Proteins - metabolism
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The messenger RNAs of many proto‐oncogenes, cytokines and lymphokines are targeted for rapid degradation through AU‐rich elements (AREs) located in their 3′ untranslated regions (UTRs). HuR, a ubiquitously expressed member of the Elav family of RNA binding proteins, exhibits specific affinities for ARE‐containing RNA sequences in vitro which correlate with their in vivo decay rates, thereby implicating HuR in the ARE‐mediated degradation pathway. We have transiently transfected HuR into mouse L929 cells and observed that overexpression of HuR enhances the stability of β‐globin reporter mRNAs containing either class I or class II AREs. The increase in mRNA stability parallels the level of HuR overexpression, establishing an in vivo role for HuR in mRNA decay. Furthermore, overexpression of HuR deletion mutants lacking RNA recognition motif 3 (RRM 3) does not exert a stabilizing effect, indicating that RRM 3 is important for HuR function. We have also developed polyclonal anti‐HuR antibodies. Immunofluorescent staining of HeLa and L929 cells using affinity‐purified anti‐HuR antibody shows that both endogenous and overexpressed HuR proteins are localized in the nucleus. By forming HeLa–L929 cell heterokaryons, we demonstrate that HuR shuttles between the nucleus and cytoplasm. Thus, HuR may initially bind to ARE‐containing mRNAs in the nucleus and provide protection during and after their export to the cytoplasmic compartment.
ISSN:0261-4189
1460-2075
DOI:10.1093/emboj/17.12.3448