Guillén I, Mullor J L, Capdevila J, Sánchez-Herrero E, Morata G, Guerrero I
Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Spain.
Development. 1995 Oct;121(10):3447-56. doi: 10.1242/dev.121.10.3447.
The adult Drosophila wing (as the other appendages) is subdivided into anterior and posterior compartments that exhibit characteristic patterns. The engrailed (en) gene has been proposed to be paramount in the specification of the posterior compartment identity. Here, we explore the adult en function by targeting its expression in different regions of the wing disc. In the anterior compartment, ectopic en expression gives rise to the substitution of anterior structures by posterior ones, thus demonstrating its role in specification of posterior patterns. The en-expressing cells in the anterior compartment also induce high levels of the hedgehog (hh) and decapentaplegic (dpp) gene products, which results in local duplications of anterior patterns. Besides, hh is able to activate en and the engrailed-related gene invected (inv) in this compartment. In the posterior compartment we find that elevated levels of en product result in partial inactivation of the endogenous en and inv genes, indicating the existence of a negative autoregulatory mechanism. We propose that en has a dual role: a general one for patterning of the appendage, achieved through the activation of secreted proteins like hh and dpp, and a more specific one, determining posterior identity, in which the inv gene may be implicated.
成年果蝇的翅膀（与其他附肢一样）被细分为具有特征性图案的前部和后部区域。有人提出，engrailed（en）基因在后部区域身份的特化过程中起着至关重要的作用。在这里，我们通过在翅芽的不同区域靶向其表达来探究成年果蝇中en基因的功能。在前部区域，异位表达的en会导致前部结构被后部结构取代，从而证明了它在后部图案特化中的作用。前部区域中表达en的细胞还会诱导高水平的刺猬蛋白（hh）和果蝇的一种基因（dpp）产物，这会导致前部图案的局部重复。此外，hh能够在该区域激活en和与engrailed相关的基因invected（inv）。在后部区域，我们发现en产物水平的升高会导致内源性en和inv基因部分失活，这表明存在一种负向自调节机制。我们提出，en具有双重作用：一种是通过激活hh和dpp等分泌蛋白来实现附肢图案化的一般作用，另一种是更具体的确定后部身份的作用，其中inv基因可能参与其中。
