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A mutation in PNPT1, encoding mitochondrial-RNA-import protein PNPase, causes hereditary hearing loss.

Authors: Von Ameln, S  Wang, G  Boulouiz, R  Rutherford, MA  Smith, GM  Li, Y  Pogoda, HM  Nurnberg, G  Stiller, B  Volk, AE  Borck, G  Hong, JS  Goodyear, RJ  Abidi, O  Nurnberg, P  Hofmann, K  Richardson, GP  Hammerschmidt, M  Moser, T  Wollnik, B  Koehler, CM  Teitell, MA  Barakat, A  Kubisch, C 
Citation: von Ameln S, etal., Am J Hum Genet. 2012 Nov 2;91(5):919-27. doi: 10.1016/j.ajhg.2012.09.002. Epub 2012 Oct 18.
Pubmed: (View Article at PubMed) PMID:23084290
DOI: Full-text: DOI:10.1016/j.ajhg.2012.09.002

A subset of nuclear-encoded RNAs has to be imported into mitochondria for the proper replication and transcription of the mitochondrial genome and, hence, for proper mitochondrial function. Polynucleotide phosphorylase (PNPase or PNPT1) is one of the very few components known to be involved in this poorly characterized process in mammals. At the organismal level, however, the effect of PNPase dysfunction and impaired mitochondrial RNA import are unknown. By positional cloning, we identified a homozygous PNPT1 missense mutation (c.1424A>G predicting the protein substitution p.Glu475Gly) of a highly conserved PNPase residue within the second RNase-PH domain in a family affected by autosomal-recessive nonsyndromic hearing impairment. In vitro analyses in bacteria, yeast, and mammalian cells showed that the identified mutation results in a hypofunctional protein leading to disturbed PNPase trimerization and impaired mitochondrial RNA import. Immunohistochemistry revealed strong PNPase staining in the murine cochlea, including the sensory hair cells and the auditory ganglion neurons. In summary, we show that a component of the mitochondrial RNA-import machinery is specifically required for auditory function.

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RGD Object Information
RGD ID: 11554169
Created: 2016-10-20
Species: All species
Last Modified: 2016-10-20
Status: ACTIVE



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RGD is funded by grant HL64541 from the National Heart, Lung, and Blood Institute on behalf of the NIH.