Origin of body axes in the mouse embryo
Origin of body axes in the mouse embryo
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DOI：
10.1016/j.gde.2007.06.001
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发表时间：
2007-08-01
影响因子：
4
通讯作者：
Hamada, Hiroshi
中科院分区：
文献类型：
--
作者：
Takaoka, Katsuyoshi;Yamamoto, Asamichi;Hamada, Hiroshi
身体的轴线是如何以及在什么发育阶段决定的？小鼠胚胎的左右轴是在胚胎日 (E) 8.0 以依赖于预先存在的位置线索的方式从头生成的。当位于远端的内脏内胚层在 E5.5 处向未来的前侧迁移时，前后 (A-P) 轴变得更早明显。这种迁移的方向是由 Lefty1 和 Cerl1（Cerberus-like 1）的不对称表达预先确定的。 Lefty1 的不对称表达甚至发生在更早的时期，即在着床囊胚的原始内胚层中，将 A-P 轴的起源推回到围着床阶段。尽管其功能意义仍有待观察，但对这种分子不对称性如何出现的研究可能有助于深入了解 A-P 极性的起源。第一个细胞命运决定发生在桑葚胚阶段。尽管二细胞或四细胞阶段的卵裂球可能存在有偏差的命运，但目前尚不清楚这种偏差是否与后来的命运有任何因果关系。
How and at what stage of development are the axes of the body determined? The left-right axis of the mouse embryo is generated de novo at embryonic day (E) 8.0 in a manner dependent on pre-existing positional cues. The anterior-posterior (A-P) axis becomes apparent earlier when distally located visceral endoderm migrates toward the future anterior side at E5.5. The direction of this migration is predetermined by asymmetric expression of Lefty1 and Cerl1(Cerberus-like 1). Asymmetric expression of Lefty1 takes place even earlier, in the primitive endoderm of the implanting blastocyst, pushing back the origin of the A-P axis to the peri-implantation stage. Although its functional significance remains to be seen, studies on how this molecular asymmetry emerges may provide insight into the origin of A-P polarity. The first cell fate decision occurs by the morula stage. Although blastomeres at the two-cell or four-cell stage may have biased fates, it is currently unknown whether this bias has any causal relation to later fate.