Microtubule-mediated transport of organelles and localization of beta-catenin to the future dorsal side of Xenopus eggs
Microtubule-mediated transport of organelles and localization of beta-catenin to the future dorsal side of Xenopus eggs
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DOI：
10.1073/pnas.94.4.1224
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发表时间：
1997-02-18
影响因子：
11.1
通讯作者：
Larabell, CA
中科院分区：
文献类型：
--
作者：
Rowning, BA;Wells, J;Larabell, CA
蛙胚胎的背腹轴在第一个细胞周期中被确定，当皮层沿着与核心相关的平行微管相对于细胞质核心旋转时。细胞质转移实验表明，尽管皮层只旋转了30度，但背侧决定因子从植物极向背侧赤道运输了90度。我们发现，在旋转过程中，内源性小细胞器沿着皮层下微管迅速向未来的背侧移动，而注入植物极的荧光羧化微珠则向赤道方向移动至少60度。我们还表明，氧化氘虽然会降低微管的旋转程度，但会拓宽背化区，并使微管随机化，同时也会使细胞器运输的方向随机化。此外，-catenin是Wnt信号通路的一个组成部分，在爪蟾中具有背化活性，在旋转结束时与卵背侧的皮质下微管共定位。我们提出皮质旋转的功能是对齐皮质下微管，然后介导背侧决定因子向卵一侧正端的运输。
The dorsal-ventral axis in frog embryos is specified during the first cell cycle, when the cortex rotates relative to the cytoplasmic core along parallel microtubules associated with the core. Cytoplasmic transfer experiments suggest that dorsal determinants are transported 90 degrees from the vegetal pole to the dorsal equator, even though the cortex rotates only 30 degrees. Here we show that, during rotation, small endogenous organelles are rapidly propelled along the subcortical microtubules toward the future dorsal side and that fluorescent carboxylated beads injected into the vegetal pole are transported at least 60 degrees toward the equator. We also show that deuterium oxide, which broadens the zone of dorsalization even though it reduces the extent of rotation and is known to randomize the microtubules, also randomizes the direction of organelle transport. Moreover, beta-catenin, a component of the Wnt signaling pathway that possesses dorsalizing activity in Xenopus, colocalizes with subcortical microtubules at the dorsal side of the egg at the end of rotation. We propose that cortical rotation functions to align subcortical microtubules, which then mediate the transport of dorsal determinants toward their plus ends on one side of the egg.