Houghton Leslie, Freeman Allison, Morgan Bruce A
Cutaneous Biology Research Center, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA.
Dev Dyn. 2003 Apr;226(4):587-95. doi: 10.1002/dvdy.10268.
The groucho-related gene (Grg) products modulate the transcriptional response to several extracellular signals, including the Wnts. In an effort to define the roles of Grgs in the morphogenesis of the feather bud, cDNAs encoding members of the Grg family were cloned from embryonic chick skin. In situ hybridization was used to localize transcripts for cGrg2, Grg3, Grg4, and Grg5 in embryos from day 6 through day 9. Expression of cGrg2, 3, and 5 is detected throughout the initial epidermal placode. As the buds mature, expression becomes limited to the posterior halves and eventually to the distal tip of the outgrowing bud. This pattern and the effects of forced activation of the bone morphogenetic protein and beta-catenin signal transduction pathways on Grg gene expression suggest that these genes act downstream of the early activation of the beta-catenin pathway that initiates placode formation. Induction of Grg genes by beta-catenin may serve as a negative feedback to modulate pathway activation while also altering the activity of other transduction pathways involved in bud patterning.
与格鲁乔相关的基因（Grg）产物可调节对包括Wnt信号在内的多种细胞外信号的转录反应。为了确定Grg在羽毛芽形态发生中的作用，从胚胎期鸡皮肤中克隆了编码Grg家族成员的cDNA。利用原位杂交技术在第6天至第9天的胚胎中定位cGrg2、Grg3、Grg4和Grg5的转录本。在最初的表皮基板中可检测到cGrg2、3和5的表达。随着芽的成熟，表达局限于后半部分，最终局限于生长芽的远端尖端。这种模式以及骨形态发生蛋白和β-连环蛋白信号转导途径的强制激活对Grg基因表达的影响表明，这些基因在启动基板形成的β-连环蛋白途径早期激活的下游起作用。β-连环蛋白对Grg基因的诱导可能作为一种负反馈来调节途径激活，同时也改变参与芽模式形成的其他转导途径的活性。
