Universität Osnabrück, Fachbereich Biologie/Chemie - Zoologie/Entwicklungsbiologie, Barbarastraße 11, 49069 Osnabrück, Germany.
Dev Biol. 2011 Feb 1;350(1):89-100. doi: 10.1016/j.ydbio.2010.11.016. Epub 2010 Nov 20.
Transport of liquids or gases in biological tubes is fundamental for many physiological processes. Our knowledge on how tubular organs are formed during organogenesis and tissue remodeling has increased dramatically during the last decade. Studies on different animal systems have helped to unravel some of the molecular mechanisms underlying tubulogenesis. Tube architecture varies dramatically in different organs and different species, ranging from tubes formed by several cells constituting the cross section, tubes formed by single cells wrapping an internal luminal space or tubes that are formed within a cell. Some tubes display branching whereas others remain linear without intersections. The modes of shaping, growing and pre-patterning a tube are also different and it is still not known whether these diverse architectures and modes of differentiation are realized by sharing common signaling pathways or regulatory networks. However, several recent investigations provide evidence for the attractive hypothesis that the Drosophila cardiogenesis and heart tube formation shares many similarities with primary angiogenesis in vertebrates. Additionally, another important step to unravel the complex system of lumen formation has been the outcome of recent studies that junctional proteins, matrix components as well as proteins acting as attractant and repellent cues play a role in the formation of the Drosophila heart lumen. In this study we show the requirement for the repulsively active Unc5 transmembrane receptor to facilitate tubulogenesis in the dorsal vessel of Drosophila. Unc5 is localized in the luminal membrane compartment of cardiomyocytes and animals lacking Unc5 fail to form a heart lumen. Our findings support the idea that Unc5 is crucial for lumen formation and thereby represents a repulsive cue acting during Drosophila heart tube formation.
液体或气体在生物管中的运输对于许多生理过程都是至关重要的。在过去的十年中，我们对管状器官在器官发生和组织重塑过程中是如何形成的认识有了显著提高。对不同动物系统的研究有助于揭示管状发生的一些分子机制。不同器官和不同物种的管状结构差异很大，从由构成横截面的几个细胞形成的管，到由单个细胞包裹内部腔空间形成的管，再到在细胞内形成的管。有些管显示出分支，而另一些管则保持线性而没有交点。管状结构的形成、生长和预模式化的方式也不同，目前尚不清楚这些不同的结构和分化模式是否是通过共享共同的信号通路或调节网络来实现的。然而，最近的几项研究提供了有吸引力的证据，表明果蝇心脏发生和心脏管形成与脊椎动物的初级血管生成有许多相似之处。此外，最近的研究还揭示了腔形成这一复杂系统的另一个重要步骤，即连接蛋白、基质成分以及作为吸引和排斥信号的蛋白在果蝇心脏腔形成中发挥作用。在这项研究中，我们表明，需要排斥活性的 Unc5 跨膜受体来促进果蝇背血管中的管状发生。Unc5 定位于心肌细胞的腔膜隔室中，缺乏 Unc5 的动物无法形成心脏腔。我们的发现支持了这样一种观点，即 Unc5 对于腔形成至关重要，因此代表了在果蝇心脏管形成过程中起作用的排斥信号。
