title: Mutation or knock-down of 17β-hydroxysteroid dehydrogenase type 10 cause loss of MRPP1 and impaired processing of mitochondrial heavy strand transcripts.
abstract: 17β-Hydroxysteroid dehydrogenase type 10 (HSD10) is multifunctional protein coded by the X-chromosomal HSD17B10 gene. Mutations in this gene cause HSD10 disease characterized by progressive neurological abnormalities and cardiomyopathy. Disease progression and severity of symptoms is unrelated to the protein's dehydrogenase activity. Recently, it was shown that HSD10 is an essential component of mitochondrial Ribonuclease P (RNase P), an enzyme required for mitochondrial tRNA processing, but little is known about the role of HSD10 in RNase P function. RNase P consists of three different proteins MRPP1, MRPP2 (HSD10) and MRPP3, each of which is essential for RNase P function. Here, we show that HSD10 protein levels are significantly reduced in fibroblasts from patients carrying the HSD17B10 mutation p.R130C. A reduction in HSD10 levels was accompanied by a reduction in MRPP1 protein but not MRPP3 protein. In HSD10 knock-down cells, MRPP1 protein content was also reduced, indicating that HSD10 is important for the maintenance of normal MRPP1 protein levels. Ectopic expression of HSD10 partially restored RNA processing in HSD10 knock-down cells and fibroblasts, and also expression of MRPP1 protein was restored to values comparable to controls. In both, patient fibroblasts and HSD10 knock-down cells, there was evidence of impaired processing of precursor tRNA transcripts of the mitochondrial heavy strand but not the light strand compared with controls. Our findings indicate that HSD10 is important for the maintenance of the MRPP1-HSD10 subcomplex of RNase P and that loss of HSD10 causes impaired mitochondrial precursor transcript processing which may explain mitochondrial dysfunction observed in HSD10 disease.
authors.affiliation: Division of Human Genetics, Innsbruck Medical University, Innsbruck 6020, Austria.
authors.forename: Andrea J
authors.initials: AJ
authors.lastname: Deutschmann
authors.affiliation: Division of Human Genetics, Innsbruck Medical University, Innsbruck 6020, Austria.
authors.forename: Albert
authors.initials: A
authors.lastname: Amberger
authors.affiliation: Division of Human Genetics, Innsbruck Medical University, Innsbruck 6020, Austria.
authors.forename: Claudia
authors.initials: C
authors.lastname: Zavadil
authors.affiliation: Institute of Human Genetics, Heidelberg University, Heidelberg 69120, Germany.
authors.forename: Herbert
authors.initials: H
authors.lastname: Steinbeisser
authors.affiliation: Department of Pediatrics, Paracelsus Medical University Salzburg, Salzburg 5020, Austria.
authors.forename: Johannes A
authors.initials: JA
authors.lastname: Mayr
authors.affiliation: Department of Pediatrics, Paracelsus Medical University Salzburg, Salzburg 5020, Austria.
authors.forename: René G
authors.initials: RG
authors.lastname: Feichtinger
authors.affiliation: Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Oerum
authors.affiliation: Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Wyatt W
authors.initials: WW
authors.lastname: Yue
authors.affiliation: Division of Human Genetics, Innsbruck Medical University, Innsbruck 6020, Austria johannes.zschocke@i-med.ac.at.
authors.forename: Johannes
authors.initials: J
authors.lastname: Zschocke
mesh_terms: D015094:3-Hydroxyacyl CoA Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D006801:Humans; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D012343:RNA, Transfer / Q000235:genetics; D043262:Ribonuclease P / Q000235:genetics / Q000378:metabolism
chemical_list: D012343:RNA, Transfer; D015094:3-Hydroxyacyl CoA Dehydrogenases; C108634:HSD17B10 protein, human; D008780:Methyltransferases; C578375:TRMT10c protein, human; D043262:Ribonuclease P