کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
10933955 1093874 2005 20 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Distinct roles for hindbrain and paraxial mesoderm in the induction and patterning of the inner ear revealed by a study of vitamin-A-deficient quail
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی بیولوژی سلول
پیش نمایش صفحه اول مقاله
Distinct roles for hindbrain and paraxial mesoderm in the induction and patterning of the inner ear revealed by a study of vitamin-A-deficient quail
چکیده انگلیسی
The hindbrain and cranial paraxial mesoderm have been implicated in the induction and patterning of the inner ear, but the precise role of the two tissues in these processes is still not clear. We have addressed these questions using the vitamin-A-deficient (VAD) quail model, in which VAD embryos lack the posterior half of the hindbrain that normally lies next to the inner ear. Using a battery of molecular markers, we show that the anlagen of the inner ear, the otic placode, is induced in VAD embryos in the absence of the posterior hindbrain. By performing grafting and ablation experiments in chick embryos, we also show that cranial paraxial mesoderm which normally lies beneath the presumptive otic placode is necessary for otic placode induction and that paraxial mesoderm from other locations cannot induce the otic placode. Two members of the fibroblast growth factor family, FGF3 and FGF19, continue to be expressed in this mesodermal population in VAD embryos, and these may be responsible for otic placode induction in the absence of the posterior hindbrain. Although the posterior hindbrain is not required for otic placode induction in VAD embryos, the subsequent patterning of the inner ear is severely disrupted. Several regional markers of the inner ear, such as Pax2, EphA4, SOHo1 and Wnt3a, are incorrectly expressed in VAD otocysts, and the sensory patches and vestibulo-acoustic ganglia are either greatly reduced or absent. Exogenous application of retinoic acid prior to 30 h of development is able rescue the VAD phenotype. By performing such rescue experiments before and after 30 h of development, we show that the inner ear defects of VAD embryos correlate with the absence of the posterior hindbrain. These results show that induction and patterning of the inner ear are governed by separate developmental processes that can be experimentally uncoupled from each other.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Developmental Biology - Volume 285, Issue 1, 1 September 2005, Pages 252-271
نویسندگان
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