Document Detail


Nonsense mutations in hERG cause a decrease in mutant mRNA transcripts by nonsense-mediated mRNA decay in human long-QT syndrome.
MedLine Citation:
PMID:  17576861     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Long-QT syndrome type 2 (LQT2) is caused by mutations in the human ether-a-go-go-related gene (hERG). More than 30% of the LQT2 mutations result in premature termination codons. Degradation of premature termination codon-containing mRNA transcripts by nonsense-mediated mRNA decay is increasingly recognized as a mechanism for reducing mRNA levels in a variety of human diseases. However, the role of nonsense-mediated mRNA decay in LQT2 mutations has not been explored.
METHODS AND RESULTS: We examined the expression of hERG mRNA in lymphocytes from patients carrying the R1014X mutation using a technique of allele-specific transcript quantification. The R1014X mutation led to a reduced level of mutant mRNA compared with that of the wild-type allele. The decrease in mutant mRNA also was observed in the LQT2 nonsense mutations W1001X and R1014X using hERG minigenes expressed in HEK293 cells or neonatal rat ventricular myocytes. Treatment with the protein synthesis inhibitor cycloheximide or RNA interference-mediated knockdown of the Upf1 protein resulted in the restoration of mutant mRNA to levels comparable to that of the wild-type minigene, suggesting that hERG nonsense mutations are subject to nonsense-mediated mRNA decay.
CONCLUSIONS: These results indicate that LQT2 nonsense mutations cause a decrease in mutant mRNA levels by nonsense-mediated mRNA decay rather than production of truncated proteins. Our findings suggest that the degradation of hERG mutant mRNA by nonsense-mediated mRNA decay is an important mechanism in LQT2 patients with nonsense or frameshift mutations.
Authors:
Qiuming Gong; Li Zhang; G Michael Vincent; Benjamin D Horne; Zhengfeng Zhou
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2007-06-18
Journal Detail:
Title:  Circulation     Volume:  116     ISSN:  1524-4539     ISO Abbreviation:  Circulation     Publication Date:  2007 Jul 
Date Detail:
Created Date:  2007-07-03     Completed Date:  2007-07-20     Revised Date:  2011-08-01    
Medline Journal Info:
Nlm Unique ID:  0147763     Medline TA:  Circulation     Country:  United States    
Other Details:
Languages:  eng     Pagination:  17-24     Citation Subset:  AIM; IM    
Affiliation:
Division of Cardiovascular Medicine, Oregon Health and Science University, 3181 SW Sam Jackson Park Rd, Portland, OR 97239, USA.
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MeSH Terms
Descriptor/Qualifier:
Adenoviridae / genetics
Adult
Aged
Animals
Animals, Newborn
Cells, Cultured / metabolism
Codon, Nonsense*
Cycloheximide / pharmacology
Ether-A-Go-Go Potassium Channels / deficiency,  genetics*
Female
Frameshift Mutation
Genes, Synthetic
Humans
Kidney
Long QT Syndrome / congenital,  genetics*,  metabolism
Lymphocytes / metabolism
Male
Middle Aged
Myocytes, Cardiac / metabolism
Pedigree
Point Mutation
Protein Synthesis Inhibitors / pharmacology
RNA Interference
RNA, Messenger / metabolism*
Rats
Rats, Sprague-Dawley
Trans-Activators / antagonists & inhibitors,  genetics,  physiology
Transfection
Grant Support
ID/Acronym/Agency:
1UL1RRO24140-01//PHS HHS; HL68854/HL/NHLBI NIH HHS; R01 HL068854-05A1/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Codon, Nonsense; 0/ERG1 potassium channel; 0/Ether-A-Go-Go Potassium Channels; 0/Protein Synthesis Inhibitors; 0/RNA, Messenger; 0/Trans-Activators; 0/UPF1 protein, human; 66-81-9/Cycloheximide
Comments/Corrections

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