Mutation in human selenocysteine transfer RNA selectively disrupts selenoprotein synthesis.

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Carlson, Bradley 
Agostini, Maura 
Moran, Carla 
Rajanayagam, Odelia 

Selenium is a trace element that is essential for human health and is incorporated into more than 25 human selenocysteine-containing (Sec-containing) proteins via unique Sec-insertion machinery that includes a specific, nuclear genome-encoded, transfer RNA (tRNA[Ser]Sec). Here, we have identified a human tRNA[Ser]Sec mutation in a proband who presented with a variety of symptoms, including abdominal pain, fatigue, muscle weakness, and low plasma levels of selenium. This mutation resulted in a marked reduction in expression of stress-related, but not housekeeping, selenoproteins. Evaluation of primary cells from the homozygous proband and a heterozygous parent indicated that the observed deficit in stress-related selenoprotein production is likely mediated by reduced expression and diminished 2'-O-methylribosylation at uridine 34 in mutant tRNA[Ser]Sec. Moreover, this methylribosylation defect was restored by cellular complementation with normal tRNA[Ser]Sec. This study identifies a tRNA mutation that selectively impairs synthesis of stress-related selenoproteins and demonstrates the importance of tRNA modification for normal selenoprotein synthesis.

Base Sequence, Child, DNA Mutational Analysis, Genetic Association Studies, Genetic Diseases, Inborn, Humans, Male, Molecular Sequence Data, Point Mutation, Polymorphism, Single Nucleotide, Protein Biosynthesis, RNA, Transfer, Amino Acid-Specific, Selenoproteins
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J Clin Invest
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American Society for Clinical Investigation
Wellcome Trust (100585/Z/12/Z)
Wellcome Trust (095564/Z/11/Z)
Our research is supported by funding from the Wellcome Trust (100585/Z/12/Z to NS, 095564/Z/11/Z to KC), the National Institute for Health Research Biomedical Research Centre Cambridge (CM, NS, KC) or Great Ormond Street (FM) and Intramural Research Program of the Center for Cancer Research, NCI, NIH (DLH).