Mutation in the iron responsive element of the L ferritin mRNA in a family with dominant hyperferritinaemia and cataract.
Nat Genet
; 11(4): 444-6, 1995 Dec.
Article
em En
| MEDLINE
| ID: mdl-7493028
ABSTRACT
The synthesis of ferritin, the iron-storing molecule, is regulated at the translational level by iron through interaction between a cytoplasmic protein, iron regulatory protein (IRP), and a conserved nucleotide motif present in the 5' non-coding region of all ferritin mRNAs--the iron responsive element (IRE). This region forms a stem-loop structure and when the supply of iron to the cells is limited, the IRP is bound to IRE and represses ferritin synthesis. Ferritin is composed of a 24-subunit protein shell surrounding an iron core. The two types of subunit, H and L, are encoded by two genes located on chromosomes 11q13 and 19q13.1, respectively. Both genes are ubiquitously expressed but transcriptional regulation mediates tissue-specific changes in the H/L mRNA ratio and isoferritin profiles. We now report the identification of a single point mutation in the IRE of the L-ferritin mRNA in members from a family affected with dominantly inherited hyperferritinaemia and cataract. This mutation consists of an A to G change in the highly conserved CAGUGU motif that constitutes the IRE loop and mediates the high-affinity interaction with the IRP. We show that this mutation abolishes the binding of IRP in vitro and leads to a high constitutive, poorly regulated L-ferritin synthesis in cultured lymphoblastoid cells established from affected patients. This is, to our knowledge, the first mutation affecting the IRP-IRE interaction and the iron-mediated regulation of ferritin synthesis. We suggest that excess production of ferritin in tissues is responsible for the hyperferritinaemia and that intracellular accumulation of ferritin leads to cataract.
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Base de dados:
MEDLINE
Assunto principal:
Catarata
/
RNA Mensageiro
/
Mutação Puntual
/
Ferritinas
/
Ferro
Tipo de estudo:
Prognostic_studies
Limite:
Female
/
Humans
/
Male
Idioma:
En
Revista:
Nat Genet
Assunto da revista:
GENETICA MEDICA
Ano de publicação:
1995
Tipo de documento:
Article
País de afiliação:
França