title: A 3'-UTR mutation creates a microRNA target site in the GFPT1 gene of patients with congenital myasthenic syndrome.
abstract: Mutations in the gene encoding glutamine-fructose-6-phosphate transaminase 1 (GFPT1) cause the neuromuscular disorder limb-girdle congenital myasthenic syndrome (LG-CMS). One recurrent GFPT1 mutation detected in LG-CMS patients is a c.*22C>A transversion in the 3'-untranslated region (UTR). Because this variant does not alter the GFPT1 open reading frame, its pathogenic relevance has not yet been established. We found that GFPT1 protein levels were reduced in myoblast cells of the patients carrying this variant. In silico algorithms predicted that the mutation creates a microRNA target site for miR-206*. Investigation of the expression of this so far unrecognized microRNA confirmed that miR-206* (like its counterpart miR-206) is abundant in skeletal muscle. MiR-206* efficiently reduced the expression of reporter constructs containing the mutated 3'-UTR while no such effect was observed with reporter constructs containing the wild-type 3'-UTR or when a specific anti-miR-206* inhibitor was added. Moreover, anti-miR-206* inhibitor treatment substantially rescued GFPT1 expression levels in patient-derived myoblasts. Our data demonstrate that the c.*22C>A mutation in the GFPT1 gene leads to illegitimate binding of microRNA resulting in reduced protein expression. We confirm that c.*22C>A is a causative mutation and suggest that formation of microRNA target sites might be a relevant pathomechanism in Mendelian disorders. Variants in the 3'-UTRs should be considered in genetic diagnostic procedures.
authors.affiliation: Friedrich-Baur-Institute, Ludwig-Maximilians-University Munich, 80336 Munich, Germany.
authors.forename: Marina
authors.initials: M
authors.lastname: Dusl
authors.affiliation: Friedrich-Baur-Institute, Ludwig-Maximilians-University Munich, 80336 Munich, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Senderek
authors.affiliation: The John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK.
authors.forename: Juliane S
authors.initials: JS
authors.lastname: Müller
authors.affiliation: Friedrich-Baur-Institute, Ludwig-Maximilians-University Munich, 80336 Munich, Germany.
authors.forename: Johannes G
authors.initials: JG
authors.lastname: Vogel
authors.affiliation: Friedrich-Baur-Institute, Ludwig-Maximilians-University Munich, 80336 Munich, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Pertl
authors.affiliation: Friedrich-Baur-Institute, Ludwig-Maximilians-University Munich, 80336 Munich, Germany.
authors.forename: Rolf
authors.initials: R
authors.lastname: Stucka
authors.affiliation: The John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK.
authors.forename: Hanns
authors.initials: H
authors.lastname: Lochmüller
authors.affiliation: Medical Clinic I, Ludwig-Maximilians-University Munich, 81377 Munich, Germany and.
authors.forename: Robert
authors.initials: R
authors.lastname: David
authors.affiliation: Friedrich-Baur-Institute, Ludwig-Maximilians-University Munich, 80336 Munich, Germany, angela.abicht@med.uni-muenchen.de.
authors.forename: Angela
authors.initials: A
authors.lastname: Abicht
mesh_terms: D020413:3' Untranslated Regions; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D015870:Gene Expression; D020869:Gene Expression Profiling; D017930:Genes, Reporter; D005945:Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing) / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D035683:MicroRNAs / Q000737:chemistry / Q000235:genetics*; D032342:Muscle Cells / Q000378:metabolism; D009154:Mutation; D020294:Myasthenic Syndromes, Congenital / Q000235:genetics* / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics*
chemical_list: D020413:3' Untranslated Regions; D035683:MicroRNAs; D012333:RNA, Messenger; C497511:GFPT1 protein, human; D005945:Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing)