Expression and regulation of the LIM homeodomain gene L3/Lhx8 suggests a role in upper lip development of the chick embryo
Expression and regulation of the LIM homeodomain gene L3/Lhx8 suggests a role in upper lip development of the chick embryo
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DOI：
10.1007/s00429-006-0078-0
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发表时间：
2006-06-01
期刊：
影响因子：
--
通讯作者：
Wanaka, Akio
中科院分区：
文献类型：
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作者：
Inoue, Masahide;Kawakami, Masayoshi;Wanaka, Akio
LIM同源结构域(LIM-Homeodomain，LHX)基因构成了一个基因家族，在模式形成和细胞类型指定中起着关键作用。我们已经发现了一个鸡L3/Lhx8基因，该基因在颅面部广泛表达。整装原位杂交结果显示，L3/Lhx8在15-31HH期的上颌突重叠区域有表达。冰冻切片显示在上皮下的间质中有这些信号。为了确定L3/Lhx8在上颌骨原基中的表达是否需要上覆口腔上皮细胞的信号，将23期HH鸡胚胎的上颌突移植到肢芽中，在有或没有口腔上皮的情况下生长间充质。有上皮的上颌间充质细胞L3/Lhx8基因表达水平较高。而L3/Lhx8在无上皮间充质中未见表达。为了进一步探索诱导LHX的信号分子(S)，将浸泡在成纤维细胞生长因子-8b或转化生长因子-β3中的微珠植入无上皮间充质移植物。转化生长因子-β3和成纤维细胞生长因子-8b微球均可诱导无上皮间充质移植物表达L3/Lhx8。我们的研究结果表明，L3/Lhx8基因参与了面部形态发生过程中上皮间充质间的相互作用，而成纤维细胞生长因子-8b和转化生长因子-β3至少部分地参与了上颌突中Lhx的表达。
LIM-homeodomain (Lhx) genes constitute a gene family that plays critical roles in the control of pattern formation and cell type specification. We have identified a chicken L3/Lhx8 gene, which was widely expressed in the craniofacial region. Whole-mount in situ hybridization showed that L3/Lhx8 mRNA was expressed from stage 15--31 HH in overlapping domains of the maxillary process. Frozen sections revealed these signals in the mesenchyme underneath the epithelium. To determine whether the expression of L3/Lhx8 in the maxillary primordia required signals from the overlying oral epithelium, maxillary processes of stage 23 HH chick embryos were transplanted into the limb bud, in which the mesenchyme was grown in the presence or absence of oral epithelium. The maxillary mesenchyme with epithelium showed significant levels of L3/Lhx8 gene expression. In contrast, no expression of L3/Lhx8 was detected in the epithelium-free mesenchyme. To further explore signaling molecule(s) responsible for Lhx induction, a bead, soaked in either Fgf-8b or TGF-beta 3, was implanted into an epithelium-free mesenchymal graft. Both TGF-beta 3 and Fgf-8b beads induced expressions of L3/Lhx8 in epithelium-free mesenchymal grafts. Our data suggest that the L3/Lhx8 gene contributes to epithelial mesenchymal interaction in facial morphogenesis and that Fgf-8b and TGF-beta 3 were, at least in part, responsible for the Lhx expression in the maxillary process.