RESUMEN
The H ferritin promoter spans approximately 150 bp, upstream of the transcription start and is composed by two cis-elements in position -132 (A box) and -62 (B-box), respectively. The A box is recognized by the transcription factor Sp1, and the B-box by a protein complex called Bbf, which includes the CAAT binding factor NF-Y. In this study we performed a functional analysis of an H ferritin promoter allele carrying a G to T substitution adjacent to the Bbf binding site, in position -69. In vitro studies with reporter constructs revealed a significantly reduced transcriptional activity of this allele compared to that of the w.t. promoter that was mirrored by a decrease in Bbf binding. In vivo, this variant genotype is accompanied by a reduced amount of the H mRNA in peripheral blood lymphocytes.
Asunto(s)
Ferritinas/genética , Polimorfismo de Nucleótido Simple , Regiones Promotoras Genéticas , Alelos , Secuencia de Bases , Sitios de Unión/genética , Factor de Unión a CCAAT/metabolismo , ADN/genética , ADN/metabolismo , Expresión Génica , Células HeLa , Humanos , Técnicas In Vitro , Unión Proteica , ARN Mensajero/genética , ARN Mensajero/metabolismo , Factor de Transcripción Sp1/metabolismo , Transcripción GenéticaRESUMEN
OBJECTIVES: The aim of this study is to evaluate the potential impact of mutations in the promoter region of the L ferritin gene on its transcriptional activity. DESIGN AND METHODS: To search for the presence of mutations in the promoter of the L gene, we amplified by PCR a DNA region of about 385 n.t. in 100 healthy subjects from Southern Italy. RESULTS: A subject carrying a C to A transition in position -216 was identified. This transition causes an increased transcriptional activity in vitro. This finding was substantiated by Real Time Quantitative PCR, which showed increased levels of L ferritin mRNA. CONCLUSIONS: A previously unidentified mutation in the promoter region of the L ferritin gene was detected in an individual. Interestingly, this subject is affected by bilateral cataract, a disease that has been correlated, in a subset of patients, with high levels of circulating ferritin. We hypothesize that changes in the expression of the L ferritin might be linked, at least to a certain extent, to the pathogenesis of this rare eye disease.