Prestin-based outer hair cell electromotility in knockin mice does not appear to adjust the operating point of a cilia-based amplifier

Jiangang Gao, Xiang Wang, Xudong Wu, Sal Aguinaga, Kristin Huynh, Shuping Jia, Keiji Matsuda, Manish Patel, Jing Zheng, MaryAnn Cheatham, David Z. He, Peter Dallos, Jian Zuo

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Abstract

The remarkable sensitivity and frequency selectivity of the mammalian cochlea is attributed to a unique amplification process that resides in outer hair cells (OHCs). Although the mammalian-specific somatic motility is considered a substrate of cochlear amplification, it has also been proposed that somatic motility in mammals simply acts as an operating-point adjustment for the ubiquitous stereocilia-based amplifier. To address this issue, we created a mouse model in which a mutation (C1) was introduced into the OHC motor protein prestin, based on previous results in transfected cells. In C1/C1 knockin mice, localization of C1-prestin, as well as the length and number of OHCs, were all normal. In OHCs isolated from C1/C1 mice, nonlinear capacitance and somatic motility were both shifted toward hyperpolarization, so that, compared with WT controls, the amplitude of cycle-by-cycle (alternating, or AC) somatic motility remained the same, but the unidirectional (DC) component reversed polarity near the OHC's presumed in vivo resting membrane potential. No physiological defects in cochlear sensitivity or frequency selectivity were detected in C1/C1 or C1/+ mice. Hence, our results do not support the idea that OHC somatic motility adjusts the operating point of a stereocilia-based amplifier. However, they are consistent with the notion that the AC component of OHC somatic motility plays a dominant role in mammalian cochlear amplification.

Original languageEnglish
Pages (from-to)12542-12547
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume104
Issue number30
DOIs
StatePublished - Jul 24 2007

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Outer Auditory Hair Cells
Cilia
Cochlea
Stereocilia
Cell Movement
Membrane Potentials
Mammals
Mutation

All Science Journal Classification (ASJC) codes

  • Genetics
  • General

Cite this

Prestin-based outer hair cell electromotility in knockin mice does not appear to adjust the operating point of a cilia-based amplifier. / Gao, Jiangang; Wang, Xiang; Wu, Xudong; Aguinaga, Sal; Huynh, Kristin; Jia, Shuping; Matsuda, Keiji; Patel, Manish; Zheng, Jing; Cheatham, MaryAnn; He, David Z.; Dallos, Peter; Zuo, Jian.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 104, No. 30, 24.07.2007, p. 12542-12547.

Research output: Contribution to journalArticle

Gao, Jiangang ; Wang, Xiang ; Wu, Xudong ; Aguinaga, Sal ; Huynh, Kristin ; Jia, Shuping ; Matsuda, Keiji ; Patel, Manish ; Zheng, Jing ; Cheatham, MaryAnn ; He, David Z. ; Dallos, Peter ; Zuo, Jian. / Prestin-based outer hair cell electromotility in knockin mice does not appear to adjust the operating point of a cilia-based amplifier. In: Proceedings of the National Academy of Sciences of the United States of America. 2007 ; Vol. 104, No. 30. pp. 12542-12547.
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