Sasagawa Satoru, Takabatake Takashi, Takabatake Yuka, Muramatsu Tatsuo, Takeshima Kazuhito
Graduate School of Human Informatics, Nagoya University, Nagoya, Japan.
Genesis. 2002 Jun;33(2):86-96. doi: 10.1002/gene.10095.
We have examined the roles of BMP4, Shh, and retinoic acid in establishing the proximal-distal and dorsal-ventral axes in the developing Xenopus eye. Misexpression of BMP4 caused the absence of an optic stalk and the expansion of dorsal and distal markers, tbx2/3/5, and pax6, at the expense of ventral and proximal markers vax2 and pax2. When Shh or Noggin, an antagonist of BMPs, was misexpressed, the reverse expression patterns of these marker genes were observed. These results suggest that BMP4 is involved in the specification of not only dorsal in the optic cup but also distal in the optic vesicle. Because Shh did not suppress bmp4 expression, unlike Noggin, Shh and BMP4 may antagonistically regulate common downstream genes in developing eye. We also found the difference between the effects of Shh and retinoic acid, another possible ventralizing factor, suggesting that Shh could promote ventralization independently of retinoic acid. These findings provide important clues to the coordinate and antagonistic actions of BMP4, Shh, and retinoic acid in axes specifications of Xenopus eyes.
我们研究了骨形态发生蛋白4（BMP4）、音猬因子（Shh）和视黄酸在非洲爪蟾发育中的眼睛建立近远轴和背腹轴过程中的作用。BMP4的错误表达导致视神经柄缺失，以及背侧和远端标记物tbx2/3/5和pax6的扩展，同时腹侧和近端标记物vax2和pax2减少。当Shh或骨形态发生蛋白拮抗剂Noggin错误表达时，观察到这些标记基因的表达模式相反。这些结果表明，BMP4不仅参与视杯背侧的特化，还参与视泡远端的特化。由于与Noggin不同，Shh不会抑制bmp4的表达，因此Shh和BMP4可能在发育中的眼睛中拮抗调节共同的下游基因。我们还发现了Shh与另一种可能的腹侧化因子视黄酸作用的差异，这表明Shh可以独立于视黄酸促进腹侧化。这些发现为BMP4、Shh和视黄酸在非洲爪蟾眼睛轴特化中的协同和拮抗作用提供了重要线索。
