Hutter H, Schnabel R
Max-Planck-Institut für Biochemie, Martinsried, FRG.
Development. 1995 Oct;121(10):3417-24. doi: 10.1242/dev.121.10.3417.
Bilateral pairs of blastomeres derived from the founder cell AB, the anterior blastomere of the 2-cell stage, in the Caenorhabditis elegans embryo are initially equivalent in their developmental potential. Recently, we showed that an induction at the 12-cell stage by a blastomere called MS is necessary to establish the differences between left and right pairs of blastomeres in the anterior part of the embryo. Further analysis of the process of creating left-right asymmetry reveals that the induction at the 12-cell stage is only the first of a series of inductions establishing the left-right asymmetry of the embryo. We describe here two further inductions that create additional asymmetries in the posterior part of the embryo. One induction occurs at the 24-cell stage among AB descendants themselves. This induction is restricted to the left side of the embryo as a consequence of the fate changes induced by MS at the 12-cell stage. The second induction requires again blastomeres of the MS lineage and also occurs around the 24-cell stage. Together these inductions establish the fate differences observed in the development of left-right pairs of blastomeres in the embryo.
源自线虫胚胎中2细胞期前体细胞AB（即前体卵裂球）的双侧卵裂球对，其初始发育潜能是等同的。最近，我们发现名为MS的卵裂球在12细胞期所产生的诱导作用，对于在胚胎前部建立左右卵裂球对之间的差异是必要的。对建立左右不对称过程的进一步分析表明，12细胞期的诱导作用仅是建立胚胎左右不对称的一系列诱导作用中的第一步。我们在此描述另外两种诱导作用，它们在胚胎后部产生额外的不对称性。一种诱导作用发生在24细胞期AB后代自身之间。由于12细胞期MS诱导产生的命运变化，这种诱导作用局限于胚胎左侧。第二种诱导作用同样需要MS谱系的卵裂球，并且也发生在24细胞期左右。这些诱导作用共同确立了胚胎中左右卵裂球对发育过程中所观察到的命运差异。
