The T-box genes are essential transcription factors during limb development. In Drosophila, Dorsocross (Doc) and optomotor-blind (omb), members of the Tbx2 and Tbx6 families, are best studied in the Drosophila wing development. Despite prominently expressed in leg discs, the specific function of these genes in leg growth is still not revealed. Here we demonstrated that Doc and omb regulated the morphogenesis of leg intermediate regions in a functionally redundant manner. Loss of Doc or omb individually did not result in any developmental defects of the legs, but loss of both genes induced significant defects in femur and proximal tibia of the adult legs. These genes located in the dorsal domain, where the Doc region expanded and cross-overlapped with the omb region corresponding to the presumptive leg intermediate region. We detected that the normal epithelial folds in the leg discs were disrupted along with dorsal repression of cell proliferation and activation of cell apoptosis when Doc and omb were both reduced. Furthermore, the dorsal expression of dachshund (dac), a canonical leg developmental gene specifying the leg intermediate region, was maintained by Doc and omb. Meanwhile, the Notch pathway was compromised in the dorsal domain when these genes were reduced, which might contribute to the joint defect of the adult leg intermediate regions. Our study provides cytological and genetic evidence for understanding the redundant function of Doc and omb in leg morphogenesis.

T-box基因是肢体发育过程中必不可少的转录因子。在果蝇中，最好在果蝇翼的发育中研究Tbx2和Tbx6家族成员的Dorsocross（Doc）和光致盲（omb）。尽管在腿间盘突出表达，但这些基因在腿生长中的特定功能仍未揭示。在这里，我们证明了Doc和omb以功能上多余的方式调节了腿部中间区域的形态。Doc或omb丢失单独地没有导致腿的任何发育缺陷，但是这两种基因的缺失都会在成年腿的股骨和胫骨近端引起明显的缺陷。这些基因位于背侧结构域，在该区域的Doc区扩展并与对应于假定的腿中间区的omb区交叉重叠。我们检测到当Doc和omb都减少时，腿椎间盘中正常的上皮褶皱被破坏，同时背侧抑制了细胞增殖并激活了细胞凋亡。此外，达克斯猎犬（dac）的背侧表达是通过指定腿中间区域来规范的腿部发育基因。Doc和omb。同时，当这些基因减少时，Notch通路在背侧区域受损，这可能是成年腿中间区域的关节缺损的原因。我们的研究为理解Doc和omb在腿部形态发生中的冗余功能提供了细胞学和遗传学证据。