Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA.
Dev Cell. 2012 Sep 11;23(3):664-73. doi: 10.1016/j.devcel.2012.08.004.
Here we identify a key role for the homeodomain proteins Extradenticle (Exd) and Homothorax (Hth) in the specification of muscle fiber fate in Drosophila. exd and hth are expressed in the fibrillar indirect flight muscles but not in tubular jump muscles, and manipulating exd or hth expression converts one muscle type into the other. In the flight muscles, exd and hth are genetically upstream of another muscle identity gene, salm, and are direct transcriptional regulators of the signature flight muscle structural gene, Actin88F. Exd and Hth also impact muscle identity in other somatic muscles of the body by cooperating with Hox factors. Because mammalian orthologs of exd and hth also contribute to muscle gene regulation, our studies suggest that an evolutionarily conserved genetic pathway determines muscle fiber differentiation.
在这里，我们确定了同源域蛋白 Extradenticle（Exd）和 Homothorax（Hth）在果蝇中肌肉纤维命运特化中的关键作用。Exd 和 Hth 在纤维状的间接飞行肌中表达，但不在管状的跳跃肌中表达，并且操纵 Exd 或 Hth 的表达会将一种肌肉类型转化为另一种。在飞行肌肉中，Exd 和 Hth 在另一个肌肉身份基因 salm 的上游，并直接转录调控标志性的飞行肌肉结构基因 Actin88F。Exd 和 Hth 还通过与 Hox 因子合作影响身体其他体壁肌肉的肌肉身份。因为 Exd 和 Hth 的哺乳动物同源物也有助于肌肉基因的调节，我们的研究表明，一个进化上保守的遗传途径决定了肌肉纤维的分化。
