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Published on: February 21, 2016
Loss of CIB2 Causes Profound Hearing Loss and Abolishes Mechanoelectrical Transduction in Mice
Yanfei Wang1,2, Jie Li3, Xuerui Yao1,2
1Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Jinan, China.
Abstract:
Calcium and integrin-binding protein 2 (CIB2) belongs to a protein family with four known members, CIB1 through CIB4, which are characterized by multiple calcium-binding EF-hand domains. Among the family members, the Cib1 and Cib2 genes are expressed in mouse cochlear hair cells, and mutations in the human CIB2 gene have been associated with nonsyndromic deafness DFNB48 and syndromic deafness USH1J. To further explore the function of CIB1 and CIB2 in hearing, we established Cib1 and Cib2 knockout mice using the clustered regularly interspaced short palindromic repeat (CRISPR)-associated Cas9 nuclease (CRISPR/Cas9) genome editing technique. We found that loss of CIB1 protein does not affect auditory function, whereas loss of CIB2 protein causes profound hearing loss in mice. Further investigation revealed that hair cell stereocilia development is affected in Cib2 knockout mice. Noticeably, loss of CIB2 abolishes mechanoelectrical transduction (MET) currents in auditory hair cells. In conclusion, we show here that although both CIB1 and CIB2 are readily detected in the cochlea, only loss of CIB2 results in profound hearing loss, and that CIB2 is essential for auditory hair cell MET.
Insights
Calcium and integrin-binding protein 2 (CIB2) is crucial for hearing. Loss of CIB2 in mice causes profound hearing loss by affecting auditory hair cell function and mechanoelectrical transduction.
Area of Science:
- Genetics and Molecular Biology
- Auditory Neuroscience
- Cell Biology
Background:
- Calcium and integrin-binding protein (CIB) family members CIB1-CIB4 feature EF-hand domains.
- CIB1 and CIB2 are expressed in mouse cochlear hair cells.
- Mutations in human CIB2 are linked to nonsyndromic (DFNB48) and syndromic (USH1J) deafness.
Purpose of the Study:
- To investigate the roles of CIB1 and CIB2 in auditory function using knockout mouse models.
- To determine the specific cellular and functional consequences of CIB1 and CIB2 loss in the cochlea.
Main Methods:
- Generation of Cib1 and Cib2 knockout mice utilizing CRISPR/Cas9 genome editing.
- Assessment of auditory function in knockout mice.
- Analysis of hair cell stereocilia development and mechanoelectrical transduction (MET) currents.
Main Results:
- Loss of CIB1 protein did not impact auditory function.
- Loss of CIB2 protein resulted in profound hearing loss in mice.
- Cib2 knockout mice exhibited defects in hair cell stereocilia development.
- CIB2 deficiency abolished mechanoelectrical transduction (MET) currents in auditory hair cells.
Conclusions:
- While both CIB1 and CIB2 are present in the cochlea, only CIB2 deficiency leads to significant hearing impairment.
- CIB2 is essential for the proper development and function of auditory hair cells, specifically for mechanoelectrical transduction.
