TY - JOUR
T1 - RNA-binding proteins HuR and PTB promote the translation of hypoxia-inducible factor 1α
AU - Galbán, Stefanie
AU - Kuwano, Yuki
AU - Pullmann, Rudolf
AU - Martindale, Jennifer L.
AU - Hyeon, Ho Kim
AU - Lal, Ashish
AU - Abdelmohsen, Kotb
AU - Yang, Xiaoling
AU - Dang, Youngjun
AU - Liu, Jun O.
AU - Lewis, Stephen M.
AU - Holcik, Martin
AU - Gorospe, Myriam
PY - 2008/1
Y1 - 2008/1
N2 - The levels of hypoxia-inducible factor 1α (HIF-1α) are tightly controlled. Here, we investigated the post-transcriptional regulation of HIF-1α expression in human cervical carcinoma HeLa cells responding to the hypoxia mimetic CoCl2. Undetectable in untreated cells, HIF-1α levels increased dramatically in CoCl2-treated cells, while HIF-1α mRNA levels were unchanged. HIF-1α translation was potently elevated by CoCl2 treatment, as determined by de novo translation analysis and by monitoring the polysomal association of HIF-1α mRNA. An internal ribosome entry site in the HIF-1α 5′ untranslated region (UTR) was found to enhance translation constitutively, but it did not further induce translation in response to CoCl2 treatment. Instead, we postulated that RNA-binding proteins HuR and PTB, previously shown to bind HIF-1α mRNA, participated in its translational upregulation after CoCl2 treatment. Indeed, both RNA-binding proteins were found to bind HIF-1α mRNA in a CoCl2-inducible manner as assessed by immunoprecipitation of endogenous ribonucleo-protein complexes. Using a chimeric reporter, polypyrimidine tract-binding protein (PTB) was found to bind the HIF-1α 3′UTR, while HuR associated principally with the 5′UTR. Lowering PTB expression or HuR expression using RNA interference reduced HIF-1α translation and expression levels but not HIF-1α mRNA abundance. Conversely, HIF-1α expression and translation in response to CoCl2 were markedly elevated after HuR overexpression. We propose that HuR and PTB jointly upregulate HIF-1α translation in response to CoCl2.
AB - The levels of hypoxia-inducible factor 1α (HIF-1α) are tightly controlled. Here, we investigated the post-transcriptional regulation of HIF-1α expression in human cervical carcinoma HeLa cells responding to the hypoxia mimetic CoCl2. Undetectable in untreated cells, HIF-1α levels increased dramatically in CoCl2-treated cells, while HIF-1α mRNA levels were unchanged. HIF-1α translation was potently elevated by CoCl2 treatment, as determined by de novo translation analysis and by monitoring the polysomal association of HIF-1α mRNA. An internal ribosome entry site in the HIF-1α 5′ untranslated region (UTR) was found to enhance translation constitutively, but it did not further induce translation in response to CoCl2 treatment. Instead, we postulated that RNA-binding proteins HuR and PTB, previously shown to bind HIF-1α mRNA, participated in its translational upregulation after CoCl2 treatment. Indeed, both RNA-binding proteins were found to bind HIF-1α mRNA in a CoCl2-inducible manner as assessed by immunoprecipitation of endogenous ribonucleo-protein complexes. Using a chimeric reporter, polypyrimidine tract-binding protein (PTB) was found to bind the HIF-1α 3′UTR, while HuR associated principally with the 5′UTR. Lowering PTB expression or HuR expression using RNA interference reduced HIF-1α translation and expression levels but not HIF-1α mRNA abundance. Conversely, HIF-1α expression and translation in response to CoCl2 were markedly elevated after HuR overexpression. We propose that HuR and PTB jointly upregulate HIF-1α translation in response to CoCl2.
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U2 - 10.1128/MCB.00973-07
DO - 10.1128/MCB.00973-07
M3 - Article
C2 - 17967866
AN - SCOPUS:37549037125
VL - 28
SP - 93
EP - 107
JO - Molecular and Cellular Biology
JF - Molecular and Cellular Biology
SN - 0270-7306
IS - 1
ER -