The function of Rac GTP-ases in inner ear haircells

2015 Fiscal Year Final Research Report

• Project/Area Number: 26870498
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Otorhinolaryngology; General anatomy (including histology/embryology)
• Research Institution: Kyoto Prefectural University of Medicine
• Principal Investigator: Nakamura Takashi 京都府立医科大学, 医学部附属病院, 病院助教 (80724179)
• Project Period (FY): 2014-04-01 – 2016-03-31
• Keywords: Rac GTPase / 内耳有毛細胞 / 小脳顆粒細胞

Outline of Final Research Achievements

We employed inner ear hair-cell and cerebellar granule neuron specific Rac GTPases conditional knockout mice to analyze the role of Rac1 and Rac3 which are key regulators of the actin cytoskeleton. We confirmed expression and activation of Rac1 and Rac3 mRNA in cochlea using in situ hybridization (ISH) and a Rac1 fluorescence resonance energy transfer (FRET) biosensor (Rac1-FRET biosensor mice). However the Rac1,3 double knockout mice showed normal hearing function and structure of cochlea hair cells. On the other hand, the mice showed severe ataxic gait when they started walking, and the phenotype was retained throughout life. We revealed that the Rac GTPases have not contributed the development and maintenance of cochlear hair cells but been essential for the formation of cerebellar granule layers.

Free Research Field

耳鼻咽喉科