Bieli Dimitri, Kanca Oguz, Gohl Daryl, Denes Alexandru, Schedl Paul, Affolter Markus, Müller Martin
Biozentrum, University of Basel, 4056 Basel, Switzerland.
Department of Molecular Biology, Princeton University, New Jersey 08540.
G3 (Bethesda). 2015 Apr 2;5(6):1129-43. doi: 10.1534/g3.115.017707.
The selector gene apterous (ap) plays a key role during the development of the Drosophila melanogaster wing because it governs the establishment of the dorsal-ventral (D-V) compartment boundary. The D-V compartment boundary is known to serve as an important signaling center that is essential for the growth of the wing. The role of Ap and its downstream effectors have been studied extensively. However, very little is known about the transcriptional regulation of ap during wing disc development. In this study, we present a first characterization of an essential wing-specific ap enhancer. First, we defined an 874-bp fragment about 10 kb upstream of the ap transcription start that faithfully recapitulates the expression pattern of ap in the wing imaginal disc. Analysis of deletions in the ap locus covering this element demonstrated that it is essential for proper regulation of ap and formation of the wing. Moreover, we showed that the mutations ap(blot) and ap(Xasta) directly affect the integrity of this enhancer, leading to characteristic wing phenotypes. Furthermore, we engineered an in situ rescue system at the endogenous ap gene locus, allowing us to investigate the role of enhancer fragments in their native environment. Using this system, we were able to demonstrate that the essential wing enhancer alone is not sufficient for normal wing development. The in situ rescue system will allow us to characterize the ap regulatory sequences in great detail at the endogenous locus.
选择基因无翅（apterous，ap）在黑腹果蝇翅膀发育过程中起关键作用，因为它控制背腹（D-V）隔室边界的建立。已知D-V隔室边界作为一个重要的信号中心，对翅膀的生长至关重要。Ap及其下游效应器的作用已得到广泛研究。然而，关于翅芽发育过程中ap的转录调控知之甚少。在本研究中，我们首次对一个必需的翅膀特异性ap增强子进行了表征。首先，我们在ap转录起始位点上游约10 kb处定义了一个874 bp的片段，该片段忠实地重现了ap在翅成虫盘的表达模式。对覆盖该元件的ap基因座缺失的分析表明，它对于ap的正确调控和翅膀的形成至关重要。此外，我们表明突变ap(blot)和ap(Xasta)直接影响该增强子的完整性，导致特征性的翅膀表型。此外，我们在内源性ap基因座构建了一个原位拯救系统，使我们能够研究增强子片段在其天然环境中的作用。使用该系统，我们能够证明仅必需的翅膀增强子不足以实现正常的翅膀发育。原位拯救系统将使我们能够在内源性基因座详细表征ap调控序列。
