Role of the hindbrain in dorsoventral but not anteroposterior axial specification of the inner ear

被引:83
作者
Bok, JW
Bronner-Fraser, M
Wu, DK
机构
[1] NIDCD, Rockville, MD 20850 USA
[2] CALTECH, Div Biol, Pasadena, CA 91125 USA
来源
DEVELOPMENT | 2005年 / 132卷 / 09期
关键词
inner ear; axis; axial specification; induction; hindbrain; rhombomere; sonic hedgehog; SHH; chicken;
D O I
10.1242/dev.01796
中图分类号
Q [生物科学];
学科分类号
07 ; 0710 ; 09 ;
摘要
An early and crucial event in vertebrate inner ear development is the acquisition of axial identities that in turn dictate the positions of all subsequent inner ear components. Here, we focus on the role of the hindbrain in establishment of inner ear axes and show that axial specification occurs well after otic placode formation in chicken. Anteroposterior (AP) rotation of the hindbrain prior to specification of this axis does not affect the normal AP orientation and morphogenesis of the inner ear. By contrast, reversing the dorsoventral (DV) axis of the hindbrain results in changing the DV axial identity of the inner ear. Expression patterns of several ventrally expressed otic genes such as NeuroD, Lunatic fringe (Lfng) and Six1 are shifted dorsally, whereas the expression pattern of a normally dorsal-specific gene, Gbx2, is abolished. Removing the source of Sonic Hedgehog (SHH) by ablating the floor plate and/or notochord, or inhibiting SHH function using an antibody that blocks SHH bioactivity results in loss of ventral inner ear structures. Our results indicate that SHH, together with other signals from the hindbrain, are important for patterning the ventral axis of the inner ear. Taken together, our studies suggest that tissue(s) other than the hindbrain confer AP axial information whereas signals from the hindbrain are necessary and sufficient for the DV axial patterning of the inner ear.
引用
收藏
页码:2115 / 2124
页数:10
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