Biology Department and Center for Computational and Integrative Biology, Science Building, 315 Penn Street, Rutgers, The State University of New Jersey, Camden, NJ 08102, USA.
Dev Biol. 2011 Jun 1;354(1):151-9. doi: 10.1016/j.ydbio.2011.03.005. Epub 2011 Mar 22.
The dorsal anterior region of the follicle cells (FCs) in the developing Drosophila egg gives rise to the respiratory eggshell appendages. These tubular structures display a wide range of qualitative and quantitative variations across Drosophila species, providing a remarkable example of a rapidly evolving morphology. In D. melanogaster, the bone morphogenetic protein (BMP) signaling pathway is an important regulator of FCs patterning and dorsal appendages morphology. To explore the mechanisms underlying the diversification of eggshell patterning, we analyzed BMP signaling in the FCs of 16 Drosophila species that span 45 million years of evolution. We found that the spatial patterns of BMP signaling in the FCs are dynamic and exhibit a range of interspecies' variations. In most of the species examined, the dynamics of BMP signaling correlate with the expression of the type I BMP receptor thickveins (tkv). This correlation suggests that interspecies' variations of tkv expression are responsible for the diversification of BMP signaling during oogenesis. This model was supported by genetic manipulations of tkv expression in the FCs of D. melanogaster that successfully recapitulated the signaling diversities found in the other species. Our results suggest that regulation of receptor expression mediates spatial diversification of BMP signaling in Drosophila oogenesis, and they provide insight into a mechanism underlying the evolution of eggshell patterning.
滤泡细胞（FCs）的背部前区在发育中的果蝇卵中产生呼吸性卵壳附肢。这些管状结构在果蝇物种中表现出广泛的定性和定量变化，为快速进化的形态提供了一个显著的例子。在黑腹果蝇中，骨形态发生蛋白（BMP）信号通路是 FCs 模式形成和背部附肢形态的重要调节因子。为了探索卵壳图案多样化的机制，我们分析了跨越 4500 万年进化的 16 种果蝇物种中 FCs 中的 BMP 信号。我们发现，FCs 中 BMP 信号的空间模式是动态的，并表现出一系列种间变化。在大多数检查的物种中，BMP 信号的动态与 I 型 BMP 受体 thickveins（tkv）的表达相关。这种相关性表明，tkv 表达的种间变化是卵发生过程中 BMP 信号多样化的原因。这一模型得到了在黑腹果蝇 FCs 中对 tkv 表达进行遗传操作的支持，这些操作成功地再现了其他物种中发现的信号多样性。我们的结果表明，受体表达的调节介导了果蝇卵发生中 BMP 信号的空间多样化，并为卵壳图案进化的机制提供了见解。
