Casares F, Calleja M, Sánchez-Herrero E
Centro de Biologia Molecular 'Severo Ochoa', Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
EMBO J. 1996 Aug 1;15(15):3934-42.
In Drosophila, the Ultrabithorax, abdominal-A and Abdominal-B HOX genes of the bithorax complex determine the identity of part of the thorax and the whole abdomen. Either the absence of these genes or their ectopic expression transform segments into the identity of different ones along the antero-posterior axis. Here we show that misexpression of Ultrabithorax, abdominal-A and, to some extent, Abdominal-B genes cause similar transformations in some of the fruitfly appendages: antennal tissue into leg tissue and wing tissue into haltere tissue. abdominal-A can fully, and Abdominal-B partially, substitute for Ultrabithorax in haltere development. By contrast, when ectopically expressed, the three genes specify different segments in regions of the main body axis like notum or abdomen. Insects may have originally used the HOX genes primarily to specify this main body axis. By contrast, the homeotic requirement to form appendages is, in some cases, non-specific.
在果蝇中，双胸复合体的超双胸、腹A和腹B同源异型基因决定了部分胸部和整个腹部的特征。这些基因的缺失或异位表达都会使体节沿前后轴转变为不同的特征。我们在此表明，超双胸、腹A以及在一定程度上腹B基因的错误表达会在果蝇的一些附肢中引起类似的转变：触角组织转变为腿部组织，翅膀组织转变为平衡棒组织。在平衡棒发育过程中，腹A可以完全替代超双胸，腹B则可以部分替代超双胸。相比之下，当这三个基因异位表达时，它们会在主体轴的区域（如背板或腹部）指定不同的体节。昆虫最初可能主要利用同源异型基因来指定这个主体轴。相比之下，在某些情况下，形成附肢的同源异型需求是非特异性的。
