Pitx1 directly controls the core limb development program to implement hindlimb identity [ChIP-Seq]

Pitx1, critical regulator of a limited hindlimb-specific gene network, targets the limb development program common to both fore- and hindlimbs in order to implement hindlimb-specific limb morphology. The gene regulatory networks governing forelimb vs. hindlimb development in mouse were investigated using expressing profiling of morphologically stage-matched e10.5 forelimbs and e11.0 hindlimbs, ChIPseq of chromatin marks, and ChIPseq of limb-specific transcription factors Pitx1 and Tbx5. The makeup of the Pitx1-directed components of the hindlimb gene network were investigated using expression profiling of Pitx1 null hindlimbs at two stages (e11.0 and e11.5).

Pitx1作为调控后肢特异性基因网络的关键调节因子，可靶向前后肢共有的肢体发育程序，从而介导后肢特异性肢体形态的形成。本研究针对小鼠前肢与后肢发育的基因调控差异，采用以下实验方法展开探究：对形态学发育阶段匹配的胚胎第10.5天（e10.5）前肢、胚胎第11.0天（e11.0）后肢进行表达谱分析；开展染色质修饰标记的染色质免疫共沉淀测序（ChIP-seq）；以及针对肢体特异性转录因子Pitx1与Tbx5的染色质免疫共沉淀测序。为解析Pitx1调控的后肢基因网络组分构成，本研究还对两个发育阶段（e11.0与e11.5）的Pitx1纯合缺失（Pitx1 null）后肢样本开展了表达谱分析。