Analysis of transcription factors expressed at the anterior mouse limb bud.
Analysis of transcription factors expressed at the anterior mouse limb bud.
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DOI：
10.1371/journal.pone.0175673
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发表时间：
2017
期刊：
影响因子：
3.7
通讯作者：
Asahara H
中科院分区：
文献类型：
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作者：
Yokoyama S;Furukawa S;Kitada S;Mori M;Saito T;Kawakami K;Belmonte JCI;Kawakami Y;Ito Y;Sato T;Asahara H
肢芽的形成、生长和分化通过转录因子、信号分子和下游基因的整合网络以时空方式精确调控。然而，肢体形态发生的确切机制仍有待阐明。在此之前，我们已经建立了一个完整的转录因子原位杂交数据库EMBRYS。基于胚胎的研究结果，我们将我们的表达模式分析集中在选择的转录因子基因上，这些基因在E9.5-E11.5肢芽中表现出相对于前后轴的空间定位和时间动态表达模式。在这些基因中，Irx 3在Shh-/-肢芽中表现出向后扩展的表达结构域，在Gli 3-/-肢芽中表现出向前减少的表达结构域，表明它们在前后图案中的重要性。为了评估基于胚胎的前调节因子逐步筛选系统，我们产生了Irx 3转基因小鼠，其中Irx 3在Prrx 1调节元件下的整个肢体间充质中表达。Irx 3功能获得模型显示了在autopods中的复杂表型，包括手指缺失，桡骨屈曲和掌骨融合，这表明Irx 3可能有助于调节肢体模式，特别是在autopods中。我们的研究结果表明，基于胚胎的基因表达分析可能有助于识别在肢体间充质模式中发挥作用的基因。
Limb bud patterning, outgrowth, and differentiation are precisely regulated in a spatio-temporal manner through integrated networks of transcription factors, signaling molecules, and downstream genes. However, the exact mechanisms that orchestrate morphogenesis of the limb remain to be elucidated. Previously, we have established EMBRYS, a whole-mount in situ hybridization database of transcription factors. Based on the findings from EMBRYS, we focused our expression pattern analysis on a selection of transcription factor genes that exhibit spatially localized and temporally dynamic expression patterns with respect to the anterior-posterior axis in the E9.5–E11.5 limb bud. Among these genes, Irx3 showed a posteriorly expanded expression domain in Shh-/- limb buds and an anteriorly reduced expression domain in Gli3-/- limb buds, suggesting their importance in anterior-posterior patterning. To assess the stepwise EMBRYS-based screening system for anterior regulators, we generated Irx3 transgenic mice in which Irx3 was expressed in the entire limb mesenchyme under the Prrx1 regulatory element. The Irx3 gain-of-function model displayed complex phenotypes in the autopods, including digit loss, radial flexion, and fusion of the metacarpal bones, suggesting that Irx3 may contribute to the regulation of limb patterning, especially in the autopods. Our results demonstrate that gene expression analysis based on EMBRYS could contribute to the identification of genes that play a role in patterning of the limb mesenchyme.