Wolfram Syndrome protein, Miner1, regulates sulphydryl redox status, the unfolded protein response, and Ca2+homeostasis
EMBO MOLECULAR MEDICINE
Authors: Wiley, Sandra E.; Andreyev, Alexander Y.; Divakaruni, Ajit S.; Karisch, Robert; Perkins, Guy; Wall, Estelle A.; van der Geer, Peter; Chen, Yi-Fan; Tsai, Ting-Fen; Simon, Melvin I.; Neel, Benjamin G.; Dixon, Jack E.; Murphy, Anne N.
Abstract
Miner1 is a redox-active 2Fe2S cluster protein. Mutations in Miner1 result in Wolfram Syndrome, a metabolic disease associated with diabetes, blindness, deafness, and a shortened lifespan. Embryonic fibroblasts from Miner1-/- mice displayed ER stress and showed hallmarks of the unfolded protein response. In addition, loss of Miner1 caused a depletion of ER Ca2+ stores, a dramatic increase in mitochondrial Ca2+ load, increased reactive oxygen and nitrogen species, an increase in the GSSG/GSH and NAD+/NADH ratios, and an increase in the ADP/ATP ratio consistent with enhanced ATP utilization. Furthermore, mitochondria in fibroblasts lacking Miner1 displayed ultrastructural alterations, such as increased cristae density and punctate morphology, and an increase in O2 consumption. Treatment with the sulphydryl anti-oxidant N-acetylcysteine reversed the abnormalities in the Miner1 deficient cells, suggesting that sulphydryl reducing agents should be explored as a treatment for this rare genetic disease.
Design and Validation of a Metabolic Disorder Resequencing Microarray (BRUM1)
HUMAN MUTATION
Authors: Bruce, Christopher K.; Smith, Matthew; Rahman, Fatima; Liu, Zhi-feng; McMullan, Dominic J.; Ball, Sarah; Hartley, Jane; Kroos, Marian A.; Heptinstall, Lesley; Reuser, Arnold J. J.; Rolfs, Arndt; Hendriksz, Chris; Kelly, Deirdre A.; Barrett, Timothy G.; MacDonald, Fiona; Maher, Eamonn R.; Gissen, Paul
Abstract
The molecular genetic diagnosis of inherited metabolic disorders is challenging. The diseases are rare, and most show locus heterogeneity. Hence, testing of the genes associated with IMDs is time consuming and often not easily available. We report a resequencing array that allows the simultaneous resequencing of up to 92 genes associated with IMDs. To validate the array, DNA samples from 51 patients with 52 different known variants (including point variants, small insertion, and deletions [indels]) in seven genes (C140RF133, GAA, NPC1, NPC2, VPS33B, WFS1, and SLC19A2) were amplified by PCR and hybridized to the array. A further patient cohort with 48 different mutations in NPCI. were analyzed blind. Out of 76 point variants, 73 were identified using automated software analysis followed by manual review. Ten insertion and deletion variants were detected in the extra tiling using mutation specific probes, with 11 heterozygous deletions and 3 heterozygous insertions. In summary, we identified 96% (95% confidence interval [CI] 89-99%) of point variants added to the array, but the pickup rate reduced to 83% (95% CI 75-89%) when insertions/deletions were included. Although the methodology has strengths and weaknesses, application of this technique could expedite diagnosis in most patients with multilocus IMDs. Hum Mutat 31:858-865,2010. (C) 2010 Wiley-Liss, Inc.