Makky Khadijah, Tekiela Jackie, Mayer Alan N
Gastroenterology Section, Department of Pediatrics and Children's Research Institute, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA.
Dev Biol. 2007 Mar 15;303(2):501-13. doi: 10.1016/j.ydbio.2006.11.030. Epub 2006 Nov 22.
The target of rapamycin (TOR) signaling pathway regulates cell growth and proliferation, however the extent to which TOR signaling mediates particular organogenesis programs remains to be determined. Here we report an examination of TOR signaling during zebrafish development, using a combination of small molecule treatment and morpholino-mediated gene knockdown. First, we amplified and sequenced the full-length cDNA for the zebrafish TOR ortholog (ztor). By in situ hybridization, we found that ztor is expressed ubiquitously in the early embryo, but displays a dynamic pattern in the gut between 48 and 72 h post-fertilization (hpf). Treatment of zebrafish embryos with rapamycin induced only a mild general developmental delay up to 72 hpf, but digestive tract development became arrested at the primitive gut tube stage. Rapamycin inhibited intestinal epithelial growth, morphogenesis and differentiation. Using morpholino-mediated gene knockdown of TOR pathway components, we show that this effect is mediated specifically by the rapamycin-sensitive TOR complex 1 (TORC1). Thus, in addition to regulating cell growth and proliferation, TOR signaling controls the developmental program guiding epithelial morphogenesis in the vertebrate intestine.
雷帕霉素靶蛋白（TOR）信号通路调控细胞生长和增殖，然而TOR信号介导特定器官发生程序的程度仍有待确定。在此，我们报告了一项在斑马鱼发育过程中对TOR信号的研究，采用了小分子处理和吗啉代介导的基因敲低相结合的方法。首先，我们扩增并测序了斑马鱼TOR直系同源基因（ztor）的全长cDNA。通过原位杂交，我们发现ztor在早期胚胎中普遍表达，但在受精后48至72小时（hpf）的肠道中呈现动态表达模式。用雷帕霉素处理斑马鱼胚胎，直至72 hpf仅诱导了轻微的整体发育延迟，但消化道发育在原始肠管阶段停滞。雷帕霉素抑制肠道上皮生长、形态发生和分化。通过吗啉代介导的TOR信号通路组分基因敲低，我们表明这种效应是由雷帕霉素敏感的TOR复合物1（TORC1）特异性介导的。因此，除了调控细胞生长和增殖外，TOR信号还控制着指导脊椎动物肠道上皮形态发生的发育程序。
