title: Increased activity of Diaphanous homolog 3 (DIAPH3)/diaphanous causes hearing defects in humans with auditory neuropathy and in Drosophila.
abstract: Auditory neuropathy is a rare form of deafness characterized by an absent or abnormal auditory brainstem response with preservation of outer hair cell function. We have identified Diaphanous homolog 3 (DIAPH3) as the gene responsible for autosomal dominant nonsyndromic auditory neuropathy (AUNA1), which we previously mapped to chromosome 13q21-q24. Genotyping of additional family members narrowed the interval to an 11-Mb, 3.28-cM gene-poor region containing only four genes, including DIAPH3. DNA sequencing of DIAPH3 revealed a c.-172G>A, g. 48G>A mutation in a highly conserved region of the 5' UTR. The c.-172G>A mutation occurs within a GC box sequence element and was not found in 379 controls. Using genome-wide expression arrays and quantitative RT-PCR, we demonstrate a 2- to 3-fold overexpression of DIAPH3 mRNA in lymphoblastoid cell lines from affected individuals. Likewise, a significant increase (approximately 1.5-fold) in DIAPH3 protein was found by quantitative immunoblotting of lysates from lymphoblastoid cell lines derived from affected individuals in comparison with controls. In addition, the c.-172G>A mutation is sufficient to drive overexpression of a luciferase reporter. Finally, the expression of a constitutively active form of diaphanous protein in the auditory organ of Drosophila melanogaster recapitulates the phenotype of impaired response to sound. To date, only two genes, the otoferlin gene OTOF and the pejvakin gene PJVK, are known to underlie nonsyndromic auditory neuropathy. Genetic testing for DIAPH3 may be useful for individuals with recessive as well as dominant inheritance of nonsyndromic auditory neuropathy.
authors.affiliation: Neuroscience Graduate Program, Molecular & Behavioral Neuroscience Institute, Division of Pediatric Otolaryngology, Department of Otolaryngology-Head and Neck Surgery, University of Michigan Health System, Ann Arbor, MI 48109, USA.
authors.forename: Cynthia J
authors.initials: CJ
authors.lastname: Schoen
authors.forename: Sarah B
authors.initials: SB
authors.lastname: Emery
authors.forename: Marc C
authors.initials: MC
authors.lastname: Thorne
authors.forename: Hima R
authors.initials: HR
authors.lastname: Ammana
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Sliwerska
authors.forename: Jameson
authors.initials: J
authors.lastname: Arnett
authors.forename: Michael
authors.initials: M
authors.lastname: Hortsch
authors.forename: Frances
authors.initials: F
authors.lastname: Hannan
authors.forename: Margit
authors.initials: M
authors.lastname: Burmeister
authors.forename: Marci M
authors.initials: MM
authors.lastname: Lesperance
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics; D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D002461:Cell Line, Transformed; D003638:Deafness / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D000080865:Formins; D020869:Gene Expression Profiling; D006319:Hearing Loss, Sensorineural / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D015151:Immunoblotting; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D020411:Oligonucleotide Array Sequence Analysis; D010375:Pedigree; D017354:Point Mutation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012689:Sequence Homology, Nucleic Acid; D013016:Sound
chemical_list: D020121:5' Untranslated Regions; D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; C484571:DIAPH3 protein, human; D029721:Drosophila Proteins; D000080865:Formins; C106890:diaphanous protein, Drosophila; D008156:Luciferases