Rossi E, Siwiec F, Yan C Y I
Departamento de Biologia Celular e do Desenvolvimento, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP, Brasil.
Braz J Med Biol Res. 2007 Oct;40(10):1333-8. doi: 10.1590/s0100-879x2006005000155. Epub 2007 Jul 31.
The dorsoventral axis of the eye is determined prior to optic cup invagination. A variety of signaling pathways have been implicated in the maintenance of the optic dorsoventral axis, including, but not limited to, bone morphogenetic protein 4, Sonic Hedgehog and retinoic acid. Here, we investigated the possible contribution of Wnt ligands to the establishment or maintenance of the optic axis by analyzing their expression pattern during early chick optic development. We performed in situ hybridization of Wnt-1, Wnt-3a, Wnt-4, and Wnt-5a during the optic vesicle, early optic cup and established optic cup stages and focused our analysis on the optic region. Our data showed that Wnt-5a, but none of the others, is expressed in the dorsal region of the eye starting from the Hamburger and Hamilton stage 14 (HH14). These results are supported by cryosections of the labeled optic region, which further reveal that Wnt-5a is expressed only in the dorsal retinal pigmented epithelium. Thus, we propose that Wnt-5a is a marker for dorsal retinal pigmented epithelium in chick embryos from HH14 to HH19.
眼睛的背腹轴在视杯内陷之前就已确定。多种信号通路参与了视背腹轴的维持，包括但不限于骨形态发生蛋白4、音猬因子和视黄酸。在此，我们通过分析鸡胚早期视发育过程中Wnt配体的表达模式，研究了Wnt配体对视轴建立或维持的可能作用。我们在视泡、早期视杯和成熟视杯阶段对视泡、早期视杯和成熟视杯阶段进行了Wnt-1、Wnt-3a、Wnt-4和Wnt-5a的原位杂交，并将分析重点放在视区。我们的数据显示，从哈伯格和汉密尔顿第14阶段（HH14）开始，Wnt-5a在眼睛的背侧区域表达，而其他Wnt配体均无此表达。标记视区的冰冻切片支持了这些结果，进一步揭示Wnt-5a仅在背侧视网膜色素上皮中表达。因此，我们提出Wnt-5a是HH14至HH19鸡胚背侧视网膜色素上皮的标志物。
