Beaton A H, Kiss I, Fristrom D, Fristrom J W
Department of Genetics, University of California, Berkeley 94720.
Genetics. 1988 Oct;120(2):453-64. doi: 10.1093/genetics/120.2.453.
The 2B5 region on the X chromosome of Drosophila melanogaster forms an early ecdysone puff at the end of the third instar. The region is coextensive with a complex genetic locus, the Broad-Complex (BR-C). The BR-C is a regulatory gene that contains two major functional domains, the br domain and the l(1)2Bc domain. BR-C mutants prevent metamorphosis, including morphogenesis of imaginal discs; br mutants prevent elongation and eversion of appendages and l(1)2Bc mutants prevent fusion of the discs. The Stubble-stubbloid (Sb-sbd) locus at 89B9-10 is best known for the effects of its mutants on bristle structure. Mutants of the BR-C and the Sb-sbd locus interact to produce severe malformation of appendages. Viable heteroallelic and homoallelic combinations of Sb-sbd mutants, including loss-of-function mutants, affect the elongation of imaginal disc appendages. Thus, the Sb-sbd+ product is essential for normal appendage elongation. Sb-sbd mutants, however, do not affect eversion or fusion of discs. Correspondingly, only BR-C mutants deficient in br function interact with Sb-sbd mutants. The interaction occurs in deficiency heterozygotes using single, wild-type doses of the BR-C, of the Sb-sbd locus, or of both loci. These last results are formally consistent with the possibility that the BR-C acts as a positive regulator of the Sb-sbd locus. The data do not exclude other possible nonregulatory interactions between the two loci, e.g., interactions between the products of both genes.
黑腹果蝇X染色体上的2B5区域在三龄期末形成一个早期蜕皮激素胀泡。该区域与一个复杂的遗传位点——宽复合体（BR-C）共延。BR-C是一个调控基因，包含两个主要功能域，即br结构域和l(1)2Bc结构域。BR-C突变体阻止变态，包括成虫盘的形态发生；br突变体阻止附肢的伸长和外翻，而l(1)2Bc突变体阻止成虫盘的融合。位于89B9 - 10的刚毛粗糙-刚毛粗糙样（Sb-sbd）位点最出名的是其突变体对刚毛结构的影响。BR-C和Sb-sbd位点的突变体相互作用会导致附肢严重畸形。Sb-sbd突变体的可存活异等位基因和同等位基因组合，包括功能丧失突变体，会影响成虫盘附肢的伸长。因此，Sb-sbd+产物对于附肢的正常伸长至关重要。然而，Sb-sbd突变体不影响成虫盘的外翻或融合。相应地，只有缺乏br功能的BR-C突变体与Sb-sbd突变体相互作用。这种相互作用发生在使用单个野生型剂量的BR-C、Sb-sbd位点或两个位点的缺失杂合子中。这些最新结果在形式上与BR-C作为Sb-sbd位点的正调控因子的可能性一致。这些数据并不排除这两个位点之间其他可能的非调控相互作用，例如，两个基因产物之间的相互作用。
