Dataset Information

Abnormal mRNA splicing but normal auditory brainstem response (ABR) in mice with the prestin (SLC26A5) IVS2-2A>G mutation.

ABSTRACT: Prestin is critical to OHC somatic motility and hearing sensitivity in mammals. Several mutations of the human SLC26A5 gene have been associated with deafness. However, whether the IVS2-2A>G mutation in the human SLC26A5 gene causes deafness remains controversial. In this study, we created a mouse model in which the IVS2-2A>G mutation was introduced into the mouse Slc26a5 gene by gene targeting. The homozygous Slc26a5 mutant mice were viable and fertile and displayed normal hearing sensitivity by ABR threshold analysis. Whole-mount immunostaining using prestin antibody demonstrated that prestin was correctly targeted to the lateral wall of OHCs, and no obvious hair cell loss occurred in mutant mice. No significant difference in the amount of prestin protein was observed between mutants and controls using western blot analysis. In OHCs isolated from mutants, the NLC was also normal. However, we observed a splicing abnormality in the Slc26a5 mRNA of the mutant mice. Eleven nucleotides were missing from the 5' end of exon 3 in Slc26a5 mRNA, but the normal ATG start codon in exon 3 was still detected. Thus, the IVS2-2A>G mutation in the Slc26a5 gene is insufficient to cause hearing loss in mice.

SUBMITTER: Zhang J

PROVIDER: S-EPMC5345126 | biostudies-literature | 2016 Aug

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Abnormal mRNA splicing but normal auditory brainstem response (ABR) in mice with the prestin (SLC26A5) IVS2-2A>G mutation.

Zhang Jian J Liu Ziyi Z Chang Aoshuang A Fang Jie J Men Yuqin Y Tian Yong Y Ouyang Xiaomei X Yan Denise D Zhang Aizhen A Sun Xiaoyang X Tang Jie J Liu Xuezhong X Zuo Jian J Gao Jiangang J

Mutation research 20160512

Prestin is critical to OHC somatic motility and hearing sensitivity in mammals. Several mutations of the human SLC26A5 gene have been associated with deafness. However, whether the IVS2-2A>G mutation in the human SLC26A5 gene causes deafness remains controversial. In this study, we created a mouse model in which the IVS2-2A>G mutation was introduced into the mouse Slc26a5 gene by gene targeting. The homozygous Slc26a5 mutant mice were viable and fertile and displayed normal hearing sensitivity b ...[more]

PMID: 27232762

Similar Datasets

Project description:Cochlear outer hair cells change their length in response to variations in membrane potential. This capability, called electromotility, is believed to enable the sensitivity and frequency selectivity of the mammalian cochlea. Prestin is a transmembrane protein required for electromotility. Homozygous prestin knockout mice are profoundly hearing impaired. In humans, a single nucleotide change in SLC26A5, encoding prestin, has been reported in association with hearing loss. This DNA sequence variation, IVS2-2A>G, occurs in the exon 3 splice acceptor site and is expected to abolish splicing of exon 3.To further explore the relationship between hearing loss and the IVS2-2A>G transition, and assess allele frequency, genomic DNA from hearing impaired and control subjects was analyzed by DNA sequencing. SLC26A5 genomic DNA sequences from human, chimp, rat, mouse, zebrafish and fruit fly were aligned and compared for evolutionary conservation of the exon 3 splice acceptor site. Alternative splice acceptor sites within intron 2 of human SLC26A5 were sought using a splice site prediction program from the Berkeley Drosophila Genome Project.The IVS2-2A>G variant was found in a heterozygous state in 4 of 74 hearing impaired subjects of Hispanic, Caucasian or uncertain ethnicity and 4 of 150 Hispanic or Caucasian controls (p = 0.45). The IVS2-2A>G variant was not found in 106 subjects of Asian or African American descent. No homozygous subjects were identified (n = 330). Sequence alignment of SLC26A5 orthologs demonstrated that the A nucleotide at position IVS2-2 is invariant among several eukaryotic species. Sequence analysis also revealed five potential alternative splice acceptor sites in intron 2 of human SLC26A5.These data suggest that the IVS2-2A>G variant may not occur more frequently in hearing impaired subjects than in controls. The identification of five potential alternative splice acceptor sites in intron 2 of human SLC26A5 suggests a potential mechanism by which expression of prestin might be maintained in cells carrying the SLC26A5 IVS2-2A>G DNA sequence variation. Additional studies are needed to evaluate the effect of the IVS2-2A>G transition on splicing of SLC26A5 transcripts and characterize the hearing status of individuals homozygous for the IVS2-2A>G variant.

Project description:BACKGROUND:In an attempt to reach remote rural areas, this study explores a community-based, pediatric hearing screening program in villages, integrating two models of diagnostic ABR testing; one using a tele-medicine approach and the other a traditional in-person testing at a tertiary care hospital. METHODS:Village health workers (VHWs) underwent a five day training program on conducting Distortion Product Oto Acoustic Emissions (DPOAE) screening and assisting in tele-ABR. VHWs conducted DPOAE screening in 91 villages and hamlets in two administrative units (blocks) of a district in South India. A two-step DPOAE screening was carried out by VHWs in the homes of infants and children under five years of age in the selected villages. Those with 'refer' results in 2nd screening were recommended for a follow-up diagnostic ABR testing in person (Group A) at the tertiary care hospital or via tele-medicine (Group B). The overall outcome of the community-based hearing screening program was analyzed with respect to coverage, refer rate, follow-up rate for 2nd screenings and diagnostic testing. A comparison of the outcomes of tele-versus in-person diagnostic ABR follow-up was carried out. RESULTS:Six VHWs who fulfilled the post training evaluation criteria were recruited for the screening program. VHWs screened 1335 children in Group A and 1480 children in Group B. The refer rate for 2nd screening was very low (0.8%); the follow-up rate for 2nd screening was between 80 and 97% across the different age groups. Integration of tele-ABR resulted in 11% improvement in follow-up compared to in-person ABR at a tertiary care hospital. CONCLUSIONS:Non-availability of audiologists and limited infrastructure in rural areas has prevented the establishment of large scale hearing screening programs. In existing programs, considerable challenges with respect to follow-up for diagnostic testing was reported, due to patients being submitted to traveling long distance to access services and potential wage losses during that time. In this program model, integration of a tele-ABR diagnostic follow-up improved follow-up in comparison to in-person follow-up. VHWs were successfully trained to conduct accurate screenings in rural communities. The very low refer rate, and improved follow-up rate reflect the success of this community-based hearing screening program.

Project description:Prestin, encoded by the gene SLC26A5, is a transmembrane protein of the cochlear outer hair cell (OHC). Prestin is required for the somatic electromotile activity of OHCs, which is absent in OHCs and causes severe hearing impairment in mice lacking prestin. In humans, the role of sequence variations in SLC26A5 in hearing loss is less clear. Although prestin is expected to be required for functional human OHCs, the clinical significance of reported putative mutant alleles in humans is uncertain.To explore the hypothesis that SLC26A5 may act as a modifier gene, affecting the severity of hearing loss caused by an independent etiology, a patient-control cohort was screened for DNA sequence variations in SLC26A5 using sequencing and allele specific methods. Patients in this study carried known pathogenic or controversial sequence variations in GJB2, encoding Connexin 26, or confirmed or suspected sequence variations in SLC26A5; controls included four ethnic populations. Twenty-three different DNA sequence variations in SLC26A5, 14 of which are novel, were observed: 4 novel sequence variations were found exclusively among patients; 7 novel sequence variations were found exclusively among controls; and, 12 sequence variations, 3 of which are novel, were found in both patients and controls. Twenty-one of the 23 DNA sequence variations were located in non-coding regions of SLC26A5. Two coding sequence variations, both novel, were observed only in patients and predict a silent change, p.S434S, and an amino acid substitution, p.I663V. In silico analysis of the p.I663V amino acid variation suggested this variant might be benign. Using Fisher's exact test, no statistically significant difference was observed between patients and controls in the frequency of the identified DNA sequence variations. Haplotype analysis using HaploView 4.0 software revealed the same predominant haplotype in patients and controls and derived haplotype blocks in the patient-control cohort similar to those generated from the International HapMap Project.Although these data fail to support a hypothesis that SLC26A5 acts as a modifier gene of GJB2-related hearing loss, the sample size is small and investigation of a larger population might be more informative. The 14 novel DNA sequence variations in SLC26A5 reported here will serve as useful research tools for future studies of prestin.

Dataset Information

Abnormal mRNA splicing but normal auditory brainstem response (ABR) in mice with the prestin (SLC26A5) IVS2-2A>G mutation.

Publications

Abnormal mRNA splicing but normal auditory brainstem response (ABR) in mice with the prestin (SLC26A5) IVS2-2A>G mutation.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets