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Proc Natl Acad Sci U S A DOI:10.1073/pnas.0810916106

Upstream open reading frames cause widespread reduction of protein expression and are polymorphic among humans.

Publication TypeJournal Article
Year of Publication2009
AuthorsCalvo, SE, Pagliarini, DJ, Mootha, VK
JournalProc Natl Acad Sci U S A
Date Published2009 May 05
Keywords5' Untranslated Regions, Base Sequence, Disease, Humans, Molecular Sequence Data, Mutation, Open Reading Frames, Polymorphism, Genetic, Protein Biosynthesis

Upstream ORFs (uORFs) are mRNA elements defined by a start codon in the 5' UTR that is out-of-frame with the main coding sequence. Although uORFs are present in approximately half of human and mouse transcripts, no study has investigated their global impact on protein expression. Here, we report that uORFs correlate with significantly reduced protein expression of the downstream ORF, based on analysis of 11,649 matched mRNA and protein measurements from 4 published mammalian studies. Using reporter constructs to test 25 selected uORFs, we estimate that uORFs typically reduce protein expression by 30-80%, with a modest impact on mRNA levels. We additionally identify polymorphisms that alter uORF presence in 509 human genes. Finally, we report that 5 uORF-altering mutations, detected within genes previously linked to human diseases, dramatically silence expression of the downstream protein. Together, our results suggest that uORFs influence the protein expression of thousands of mammalian genes and that variation in these elements can influence human phenotype and disease.


Alternate JournalProc. Natl. Acad. Sci. U.S.A.
PubMed ID19372376
PubMed Central IDPMC2669787
Grant ListR01 GM077465 / GM / NIGMS NIH HHS / United States
R01 GM077465-04 / GM / NIGMS NIH HHS / United States
GM077465 / GM / NIGMS NIH HHS / United States