An mRNA loop/bulge in the ferritin iron-responsive element forms in vivo and Was detected by radical probing with Cu-1,10-phenantholine and iron regulatory protein footprinting.
J Biol Chem
; 277(4): 2373-6, 2002 Jan 25.
Article
em En
| MEDLINE
| ID: mdl-11714692
ABSTRACT
Messenger RNA (mRNA) regulatory elements often form helices specifically distorted by loops or bulges, which control protein synthesis rates in vitro. Do such three-dimensional RNA structures form in vivo? We now observe formation of the internal loop/bulge (IL/B structure) in the IRE (iron-responsive element) of ferritin mRNA expressed in HeLa cells, using radical cleavage with Cu-phen (Cu-1,10-phenantholine), and protection of the loop/bulge by the regulatory protein (IRP), expressed by cotransfection. Cu-phen, a metal coordination complex (MC) selected because of binding and cleavage at the IL/B in solution, recognized the same site in mRNA in HeLa cells. Endogenous reductants apparently substituted for the sulfhydryl activation of Cu-phen cleavage in solution. Selective RNA IL/B recognition by Cu-phen in vivo is emphasized by resistance to cleavage of a mutated, IL/B IRE in ferritin mRNA. Development of small MCs even more selective than Cu-phen can exploit three-dimensional mRNA or viral RNA structures in vivo to manipulate RNA function. Formation in vivo of the IL/B in the ferritin IRE, which is associated in vitro with greater repression than single IRE structures in other mRNAs, likely contributes to larger derepression of ferritin synthesis in vivo triggered by signals for the IRE/IRP system.
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Bases de dados:
MEDLINE
Assunto principal:
Fenantrolinas
/
RNA Mensageiro
/
Quelantes
/
Proteínas de Ligação a RNA
/
Elementos de Resposta
/
Ferritinas
/
Proteínas Ferro-Enxofre
Tipo de estudo:
Prognostic_studies
Limite:
Humans
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2002
Tipo de documento:
Article
País de afiliação:
Estados Unidos