Hooper Joan E
Medical Research Council, Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, UK.
EMBO J. 1986 Sep;5(9):2321-2329. doi: 10.1002/j.1460-2075.1986.tb04500.x.
The segmental musculature of Drosophila melanogaster larvae consists of 24-30 muscles per segment. Unique patterns of muscles are found in the three thoracic segments and the first and last abdominal segments; the remaining abdominal segments share the same pattern. Mutations in Ultrabithorax (Ubx) cause partial transformation of the muscle pattern of larval abdominal segments towards metathorax. The muscles of the thorax are not affected. In the first two abdominal segments the changes include the loss of at least 11 ;abdominal' muscles and the gain of 11 ;thoracic' muscles. Less extensive transformations are seen in more posterior abdominal segments. Anterobithorax, bithorax, postbithorax and bithoraxoid mutations also induce transformations of the larval musculature. Each allelic group affects a domain that is a subset of the entire Ubx domain but these domains are not restricted to compartments or segments and may extend through as many as five segments. In the muscles the segmental distribution of Ubx antigen correlates with the segments affected by Ubx mutations. The different domains of Ubx in mesoderm and ectoderm argue that the segmental diversity of the muscle pattern is not simply induced by the overlying epidermis and that Ubx function in the mesoderm is required for the correct development of abdominal segments.
黑腹果蝇幼虫的分节肌肉组织每节由24至30块肌肉组成。在三个胸节以及第一和最后一个腹节中发现了独特的肌肉模式；其余腹节具有相同的模式。超双胸（Ubx）基因的突变会导致幼虫腹节的肌肉模式部分向中胸转变。胸部的肌肉不受影响。在前两个腹节中，变化包括至少11块“腹部”肌肉的缺失和11块“胸部”肌肉的增加。在更靠后的腹节中观察到的转变程度较小。前双胸、双胸、后双胸和双胸样突变也会诱导幼虫肌肉组织的转变。每个等位基因群影响的区域是整个Ubx区域的一个子集，但这些区域不限于隔室或节段，可能延伸多达五个节段。在肌肉中，Ubx抗原的节段分布与受Ubx突变影响的节段相关。Ubx在中胚层和外胚层中的不同区域表明，肌肉模式的节段多样性并非简单地由覆盖其上的表皮诱导，并且中胚层中Ubx的功能是腹节正确发育所必需的。
