Rizzo Nicholas P, Bejsovec Amy
Department of Biology, Duke University, Durham, NC 27708, USA.
Department of Biology, Duke University, Durham, NC 27708, USA
Development. 2017 Jun 15;144(12):2248-2258. doi: 10.1242/dev.150169. Epub 2017 May 15.
During development, extracellular signals are integrated by cells to induce the transcriptional circuitry that controls morphogenesis. In the fly epidermis, Wingless (Wg)/Wnt signaling directs cells to produce either a distinctly shaped denticle or no denticle, resulting in a segmental pattern of denticle belts separated by smooth, or 'naked', cuticle. Naked cuticle results from Wg repression of (), which encodes a transcription factor required for denticle construction. We have discovered that although the promoter responds differentially to altered Wg levels, Svb alone cannot produce the morphological diversity of denticles found in wild-type belts. Instead, a second Wg-responsive transcription factor, SoxNeuro (SoxN), cooperates with Svb to shape the denticles. Co-expressing ectopic with rescued diverse denticle morphologies. Conversely, removing activity eliminated the residual denticles found in mutant embryos. Furthermore, several known Svb target genes are also activated by SoxN, and we have discovered two novel target genes of SoxN that are expressed in denticle-producing cells and that are regulated independently of Svb. We conclude that proper denticle morphogenesis requires transcriptional regulation by both SoxN and Svb.
在发育过程中,细胞整合细胞外信号以诱导控制形态发生的转录回路。在果蝇表皮中,无翅(Wg)/Wnt信号传导引导细胞产生形状独特的齿状结构或不产生齿状结构,从而形成由光滑或“裸露”表皮隔开的齿状带的节段模式。裸露的表皮是由于Wg对()的抑制作用,()编码齿状结构构建所需的转录因子。我们发现,尽管()启动子对Wg水平的变化有不同的反应,但单独的Svb并不能产生野生型带中发现的齿状结构的形态多样性。相反,第二个Wg反应性转录因子SoxNeuro(SoxN)与Svb协同作用来塑造齿状结构。与()共表达异位()挽救了多种齿状结构形态。相反,去除()活性消除了在()突变胚胎中发现的残余齿状结构。此外,几个已知的Svb靶基因也被SoxN激活,并且我们发现了两个新的SoxN靶基因,它们在产生齿状结构的细胞中表达并且独立于Svb进行调节。我们得出结论,正确的齿状结构形态发生需要SoxN和Svb的转录调控。