González-Reyes A, Morata G
Centro de Biología Molecular (CSIC-UAM), Universidad Autónoma, Madrid, Spain.
Development. 1991 Dec;113(4):1459-71. doi: 10.1242/dev.113.4.1459.
By using a hsp70-Ubx fusion gene, we have ectopically expressed a Ubx product in the embryonic head primordia and studied the developmental effects on the larval head. We find that after high and persistent levels of Ubx product, the head is replaced by three (C1, C2 and C3) abdominal-like denticle belts. The C2 and C3 belts are the homeotic transformations of parasegments 1 and 2, respectively, while the C1 belt probably derives from the transformation and subsequent fusion of the most anterior procephalic primordia. On the basis of their response to the Ubx product and other arguments, we propose that the larval head is made of two genetically distinct components; one is the procephalon and the anterior region of the mandibular lobe, and the other is part of the parasegmental trunk and includes parasegments 1 and 2. Our results also indicate that most or all the larval head structures derive from precursor cells of ventral origin.
通过使用热休克蛋白70-超双胸蛋白（hsp70-Ubx）融合基因，我们已在胚胎头部原基中异位表达了超双胸蛋白产物，并研究了其对幼虫头部发育的影响。我们发现，在高水平且持续表达超双胸蛋白产物后，头部被三条（C1、C2和C3）类似腹部的齿带所取代。C2和C3带分别是副节1和副节2的同源异型转化，而C1带可能源自最前端的前脑原基的转化及随后的融合。基于它们对超双胸蛋白产物的反应及其他论据，我们提出幼虫头部由两个基因上不同的成分组成；一个是前脑和下颌叶的前部区域，另一个是副节躯干的一部分，包括副节1和副节2。我们的结果还表明，大多数或所有幼虫头部结构都源自腹侧起源的前体细胞。
