Department of Biology, University of Osnabrück, Barbarastraße 11, D-49069 Osnabrück, Germany.
Dev Biol. 2013 Sep 15;381(2):446-59. doi: 10.1016/j.ydbio.2013.05.027. Epub 2013 Jun 6.
The Hand basic helix-loop-helix transcription factors play an important role in the specification and patterning of various tissues in vertebrates and invertebrates. Here, we have investigated the function of Hand in the development of the Drosophila wing hearts which consist of somatic muscle cells as well as a mesodermally derived epithelium. We found that Hand is essential in both tissues for proper organ formation. Loss of Hand leads to a reduced number of cells in the mature organ and loss of wing heart functionality. In wing heart muscles Hand is required for the correct positioning of attachment sites, the parallel alignment of muscle cells, and the proper orientation of myofibrils. At the protein level, α-Spectrin and Dystroglycan are misdistributed suggesting a defect in the costameric network. Hand is also required for proper differentiation of the wing heart epithelium. Additionally, the handC-GFP reporter line is not active in the mutant suggesting an autoregulatory role of Hand in wing hearts. Finally, in a candidate-based RNAi mediated knock-down approach we identified Daughterless and Nautilus as potential dimerization partners of Hand in wing hearts.
手基本螺旋-环-螺旋转录因子在脊椎动物和无脊椎动物的各种组织的特化和模式形成中发挥重要作用。在这里，我们研究了 Hand 在果蝇翅膀心脏发育中的功能，果蝇翅膀心脏由体节肌肉细胞以及中胚层衍生的上皮组成。我们发现 Hand 在手稿和上皮组织中对于器官的正常形成都是必需的。Hand 的缺失导致成熟器官中的细胞数量减少，并且丧失了翅膀心脏的功能。在翅膀心脏肌肉中，Hand 对于附着点的正确定位、肌细胞的平行排列以及肌原纤维的正确取向是必需的。在蛋白质水平上，α- spectrin 和 dystroglycan 分布异常，提示着细胞骨架网络的缺陷。Hand 对于翅膀心脏上皮的正常分化也是必需的。此外，在手稿突变体中，handC-GFP 报告基因不活跃，这表明 Hand 在翅膀心脏中具有自调节作用。最后，在基于候选物的 RNAi 介导敲低方法中，我们鉴定出 Daughterless 和 Nautilus 是翅膀心脏中 Hand 的潜在二聚化伙伴。
