Hutter H, Schnabel R
Max-Planck-Institut für Biochemie, Martinsried, FRG.
Development. 1995 May;121(5):1559-68. doi: 10.1242/dev.121.5.1559.
In a C. elegans embryo the third cleavages of descendants of the anterior blastomere AB of the 2-cell stage create pairs of blastomeres that develop differently. By laser ablation experiments we show that the fates of all the posterior daughters of this division depend on an induction occurring three cleavages before these blastomeres are born. The time of induction precludes a direct effect on cell fate. Alternatively, we suggest that the induction creates a heritable cell polarity which is propagated through several divisions. We suggest a model to demonstrate how a signal could be propagated through several rounds of cell division. An important implication of our observations is that this early induction acts to specify blastomere identity, not tissue type. A detailed lineage analysis revealed that altering the inductive signal alters complex lineage patterns as a whole. The induction described here, together with two inductions described previously can be used to illustrate how the anterior portion of the C. elegans embryo can be successively subdivided into blastomeres with unique developmental potential.
在秀丽隐杆线虫胚胎中，二细胞期前体卵裂球AB的后代进行第三次卵裂时，会产生发育方式不同的卵裂球对。通过激光消融实验，我们发现该分裂所有后向子代的命运取决于在这些卵裂球产生前三轮卵裂时发生的诱导作用。诱导时间排除了对细胞命运的直接影响。另外，我们认为这种诱导产生了一种可遗传的细胞极性，该极性通过多轮分裂得以传递。我们提出了一个模型来展示信号如何通过多轮细胞分裂进行传递。我们观察结果的一个重要意义在于，这种早期诱导作用是为了确定卵裂球的身份，而非组织类型。详细的谱系分析表明，改变诱导信号会整体改变复杂的谱系模式。此处描述的诱导作用，与之前描述的另外两种诱导作用一起，可用于说明秀丽隐杆线虫胚胎的前部如何被依次细分为具有独特发育潜能的卵裂球。
