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Author Notes:

Correspondence: Xi Lin, Ph.D., Departments of Otolaryngology and Cell Biology, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322. E-mail: xlin2@emory.edu

Acknowledgments: The authors thank Dr. Philine Wangemann for providing valuable comments on the manuscript.


Research Funding:

Grant sponsor: National Institutes of Health; Grant numbers: RO1-DC04709 and RO1-DC006483 (to X.L.) and R01 DC06630 (to R.S.); Grant sponsor: Woodruff Foundation (to X.L.); Grant sponsor: German Research Association (to K.W.); Grant sponsor: Fritz Thyssen Foundation (to K.W.); Grant sponsor: the National Organization for Hearing Research (to W.T.); Grant sponsor: the Deafness Research Foundation (to W.T.); Grant sponsor: the Hebei Provincial Government of China (to Q.Y.).


  • hair cell degeneration
  • vestibular sensory organs
  • saccule
  • connexin
  • gap junction
  • vestibular adaptation
  • congenital hearing loss

Analysis of Connexin Subunits Required for the Survival of Vestibular Hair Cells


Journal Title:

Journal of Comparative Neurology


Volume 504, Number 5


, Pages 499-507

Type of Work:

Article | Post-print: After Peer Review


Mutations in connexin (Cx) genes are responsible for a large proportion of human inherited prelingual deafness cases. The most commonly found human Cx mutations are either Cx26 or Cx30 deletions. Histological observations made in the organ of Corti of homozygous Cx26 and Cx30 gene knockout mice show that cochlear hair cells degenerate after the onset of hearing. However, it is unclear whether vestibular hair cells undergo similar degeneration in connexin knockout mice. To address this question, we first examined expression patterns of Cx26 and Cx30 in the saccule, utricle, and ampulla by immunolabeling. In wild-type mice, Cx26 and Cx30 immunoreactivity was found extensively in vestibular supporting cells and connective tissue cells, and the two Cxs were co-localized in most gap junction (GJ) plaques. Targeted deletion of the Cx30 gene, which caused little change in Cx26 expression pattern, resulted in a significant and age-related loss of vestibular hair cells only in the saccule. dUTP nick end labeling (TUNEL) staining also revealed on-going apoptosis specifically in saccular hair cells of Cx30−/− mice. These results indicated that hair cell survival in the utricle and ampulae does not require Cx30. Importantly, over-expressing the Cx26 gene from a modified bacterial artificial chromosome in the Cx30−/− background rescued the saccular hair cells. These results suggest that it is the reduction in the total amount of GJs rather than the specific loss of Cx30 that underlies saccular hair cell death in Cx30−/− mice. Hybrid GJs co-assembled from Cx26 and Cx30 were not essential for the survival of saccular hair cells.

Copyright information:

© 2007 Wiley-Liss, Inc.

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