Jinwoong Boka,1, Steven Raftb, Kyoung-Ah Konga, Soo Kyung Kooc, Ursula C. Dragerd, and Doris K. Wub,1
aDepartment of Anatomy, BK21 Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, South Korea;
bNational Institute on Deafness and Other Communication Disorders, Rockville, MD 20850;
cDepartment of Biomedical Sciences, National Institute of Health, Osong 363-951, South Korea; and
dDepartment of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01655
Edited* by Brigid L.M. Hogan, Duke University Medical Center, Durham, NC, and approved November 11, 2010 (received for review July 19, 2010)
Vertebrate hearing and balance are based in complex asymmetries of inner ear structure. Here, we identify retinoic acid (RA) as an extrinsic signal that acts directly on the ear rudiment to affect its compartmentalization along the anterior-posterior axis. A rostrocaudal wave of RA activity, generated by tissues surrounding the nascent ear, induces distinct responses from anterior and posterior halves of the inner ear rudiment. Prolonged response to RA by posterior otic tissue correlates with Tbx1 transcription and formation of mostly nonsensory inner ear structures. By contrast, anterior otic tissue displays only a brief response to RA and forms neuronal elements and most sensory structures of the inner ear.
axial specification, developmental compartments, morphogen
1To whom correspondence may be addressed.
Author contributions: J.B. and D.K.W. designed research; J.B., S.R., K.-A.K., S.K.K., and D.K.W. performed research; U.C.D. contributed new reagents/analytic tools; J.B., S.R., K.-A.K., S.K.K., and D.K.W. analyzed data; and J.B., S.R., U.C.D., and D.K.W. wrote the paper.
The authors declare no conflict of interest.
*This Direct Submission article had a prearranged editor.
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