Granata Alessandra, Quaderi Nandita A
MRC Centre for Developmental Neurobiology, King's College London, 4th Floor New Hunt's House, Guy's Hospital Campus, London SE1 1UL, UK.
Gene Expr Patterns. 2005 Apr;5(4):529-31. doi: 10.1016/j.modgep.2004.11.003. Epub 2004 Dec 15.
Avian left-right (L/R) axis determination involves the establishment of asymmetric gene expression in Hensen's node, resulting in two discrete signalling pathways on the left and right sides of the embryo. The extracellular signalling molecule Sonic Hedgehog (SHH) is known to be an important left-side determinant. Transcription of Shh is initially bilateral in Hensen's node (stage 4), but is restricted to the left side by stage 5. The Gli genes (Gli1, Gli2 and Gli3) are the main transcriptional mediators of the Hedgehog pathway in vertebrates. GLI1 and GLI2 are primarily transcriptional activators of Hedgehog target genes, while GLI3 is primarily a transcriptional repressor of Hedgehog targets. In order to gain insight into the mechanisms of asymmetrical Hedgehog signal transduction in the node, we have analysed the expression patterns of the Gli genes in Hensen's node from stage 4 to stage 8. Here, we reveal that the Gli genes are asymmetrically expressed in Hensen's node: Gli1 and Gli2, are expressed on the left side, while Gli3 is expressed on the right side.
鸟类左右（L/R）轴的确定涉及在亨氏结中建立不对称基因表达，从而在胚胎的左右两侧产生两条离散的信号通路。已知细胞外信号分子音猬因子（SHH）是重要的左侧决定因素。Shh的转录最初在亨氏结中是双侧的（第4阶段），但到第5阶段时局限于左侧。Gli基因（Gli1、Gli2和Gli3）是脊椎动物中刺猬因子信号通路的主要转录调节因子。GLI1和GLI2主要是刺猬因子靶基因的转录激活因子，而GLI3主要是刺猬因子靶标的转录抑制因子。为了深入了解结中不对称刺猬因子信号转导的机制，我们分析了第4阶段到第8阶段亨氏结中Gli基因的表达模式。在此，我们揭示Gli基因在亨氏结中不对称表达：Gli1和Gli2在左侧表达，而Gli3在右侧表达。
