A novel HFE mutation (c.del478) results in nonsense-mediated decay of the mutant transcript in a hemochromatosis patient

Pointon, Jennifer J.; Lok, Chun Yu; Shearman, Jeremy D.; Suckling, Richard; Rochette, Jacques; Merryweather‐Clarke, Alison T.; Robson, Kathryn

doi:10.1016/j.bcmd.2009.04.007

Cited by 10 publications

(5 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This mutation consists in a single nucleotide deletion (c.del478) causing a frameshift that introduces a premature termination codon in exon four. The authors have demonstrated that c.del478 allele accounts for only 2% of the total cytoplasmic HFE mRNA showing that the mutant transcript is degraded by NMD [42]. In the light of our results, since the HFE mRNA containing exon seven is capable of, at some extent, escape NMD, the introduction of a nonsense mutation could lead most of the corresponding transcripts to NMD.…”

Section: Discussionmentioning

confidence: 47%

“…This may reflect the overexpression system in use. Moreover, it cannot be disregarded that, in the study by Pointon et al [42], the iron overload observed in the patient could induce preferential polyadenylation at exon six and ultimately would increase levels of the wild type transcripts relatively to those of the mutated allele.…”

Section: Discussionmentioning

confidence: 95%

“…To our knowledge, there are few nonsense mutations reported in the human HFE gene [38], [40]–[42]. Yet, only one of these mutations has been studied in what concerns its ability to commit the mRNA to NMD [42].…”

Section: Discussionmentioning

confidence: 99%

“…Yet, only one of these mutations has been studied in what concerns its ability to commit the mRNA to NMD [42]. This mutation consists in a single nucleotide deletion (c.del478) causing a frameshift that introduces a premature termination codon in exon four.…”

Section: Discussionmentioning

confidence: 99%

See 3 more Smart Citations

Alternative Polyadenylation and Nonsense-Mediated Decay Coordinately Regulate the Human HFE mRNA Levels

et al. 2012

View full text Add to dashboard Cite

Nonsense-mediated decay (NMD) is an mRNA surveillance pathway that selectively recognizes and degrades defective mRNAs carrying premature translation-termination codons. However, several studies have shown that NMD also targets physiological transcripts that encode full-length proteins, modulating their expression. Indeed, some features of physiological mRNAs can render them NMD-sensitive. Human HFE is a MHC class I protein mainly expressed in the liver that, when mutated, can cause hereditary hemochromatosis, a common genetic disorder of iron metabolism. The HFE gene structure comprises seven exons; although the sixth exon is 1056 base pairs (bp) long, only the first 41 bp encode for amino acids. Thus, the remaining downstream 1015 bp sequence corresponds to the HFE 3′ untranslated region (UTR), along with exon seven. Therefore, this 3′ UTR encompasses an exon/exon junction, a feature that can make the corresponding physiological transcript NMD-sensitive. Here, we demonstrate that in UPF1-depleted or in cycloheximide-treated HeLa and HepG2 cells the HFE transcripts are clearly upregulated, meaning that the physiological HFE mRNA is in fact an NMD-target. This role of NMD in controlling the HFE expression levels was further confirmed in HeLa cells transiently expressing the HFE human gene. Besides, we show, by 3′-RACE analysis in several human tissues that HFE mRNA expression results from alternative cleavage and polyadenylation at four different sites – two were previously described and two are novel polyadenylation sites: one located at exon six, which confers NMD-resistance to the corresponding transcripts, and another located at exon seven. In addition, we show that the amount of HFE mRNA isoforms resulting from cleavage and polyadenylation at exon seven, although present in both cell lines, is higher in HepG2 cells. These results reveal that NMD and alternative polyadenylation may act coordinately to control HFE mRNA levels, possibly varying its protein expression according to the physiological cellular requirements.

show abstract

Section: Discussionmentioning

confidence: 47%

Section: Discussionmentioning

confidence: 95%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Alternative Polyadenylation and Nonsense-Mediated Decay Coordinately Regulate the Human HFE mRNA Levels

et al. 2012

View full text Add to dashboard Cite

show abstract

“…6 DNA sequencing of the exons, exon-intron boundaries and the 5' untranslated region of the HFE, HAMP, HJV/HFE2, TFR2 and SLC40A1 genes was undertaken as previously described. 19,20 When a new HFE mutant was identified, it was systematically confirmed on a second sample using a sequencing approach or PCR-RFLP if a restriction site was altered by the mutation. Its absence was verified on a sample of 100 unrelated chromosomes of controls without iron overload.…”

Section: Design and Methodsmentioning

confidence: 99%

Iron overload in HFE C282Y heterozygotes at first genetic testing: a strategy for identifying rare HFE variants

Aguilar-Martinez

Grandchamp²,

Cunat³

et al. 2011

Haematologica

View full text Add to dashboard Cite

BackgroundHeterozygotes for the p.Cys282Tyr (C282Y) mutation of the HFE gene do not usually express a hemochromatosis phenotype. Apart from the compound heterozygous state for C282Y and the widespread p.His63Asp (H63D) variant allele, other rare HFE mutations can be found in trans on chromosome 6. Design and MethodsWe performed molecular investigation of the genes implicated in hereditary hemochromatosis in six patients who presented with iron overload but were simple heterozygotes for the HFE C282Y mutation at first genetic testing. Functional impairment of new variants was deduced from computational methods including molecular modeling studies. ResultsWe identified four rare HFE mutant alleles, three of which have not been previously described. One mutation is a 13-nucleotide deletion in exon 6 (c.1022_1034del13, p.His341_Ala345>LeufsX119), which is predicted to lead to an elongated and unstable protein.The second one is a substitution of the last nucleotide of exon 2 (c.340G>A, p.Glu114Lys) which modifies the relative solvent accessibility in a loop interface. The third mutation, p.Arg67Cys, also lies in exon 2 and introduces a destabilization of the secondary structure within a loop of the α1 domain. We also found the previously reported c.548T>C (p.Leu183Pro) missense mutation in exon 3. No other known iron genes were mutated. We present an algorithm at the clinical and genetic levels for identifying patients deserving further investigation. ConclusionsOur results suggest that additional mutations in HFE may have a clinical impact in C282Y carriers. In conjunction with results from previously described cases we conclude that an elevated transferrin saturation level and elevated hepatic iron index should indicate the utility of searching for further HFE mutations in C282Y heterozygotes prior to other iron gene studies.

show abstract

Genetic Testing for Disorders of Iron Homeostasis

Barton

Lee

Edwards

2011

Iron Physiology and Pathophysiology in Humans

View full text Add to dashboard Cite

A novel HFE mutation (c.del478) results in nonsense-mediated decay of the mutant transcript in a hemochromatosis patient

Cited by 10 publications

References 25 publications

Alternative Polyadenylation and Nonsense-Mediated Decay Coordinately Regulate the Human HFE mRNA Levels

Alternative Polyadenylation and Nonsense-Mediated Decay Coordinately Regulate the Human HFE mRNA Levels

Iron overload in HFE C282Y heterozygotes at first genetic testing: a strategy for identifying rare HFE variants

Genetic Testing for Disorders of Iron Homeostasis

Contact Info

Product

Resources

About