Sluder G, Miller F J, Lewis K, Davison E D, Rieder C L
Worcester Foundation for Experimental Biology, Shrewsbury, Massachusetts 01545.
Dev Biol. 1989 Feb;131(2):567-79. doi: 10.1016/s0012-1606(89)80027-2.
The mature egg inherits a centrosome from the second meiotic spindle, and the sperm introduces a second centrosome at fertilization. Since only one of these centrosomes survives to be used in development, specific mechanisms must exist to control centrosome inheritance. To investigate how centrosome inheritance is controlled we used starfish eggs as a model system, because they undergo meiosis after fertilization. As a result, the fate of the maternal and paternal centrosomes can be followed by light microscopy and experimentally manipulated in vivo. We show initially that only the paternal centrosome is used in starfish zygote development; the maternal centrosome retained from meiosis II is functionally lost before first mitosis. We then tested a number of possible ways in which the zygote could exert this differential control over the stability of centrosomes initially residing in the same cytoplasm. The results of these experiments can be summarized as follows: (1) Although the microtubule organizing center activity of the maternal centrosome is not degraded after meiosis, the ability of this centrosome to double at successive mitoses is lost. (2) The sperm centrosome is not "masked" from cytoplasmic conditions which could destabilize all centrosomes during or after the meiotic sequence. (3) The functional loss of the maternal centrosome is not due to its cortical location. (4) The loss of this doubling capacity is determined by the egg, not by putative inhibitory factors from the fertilizing sperm. (5) The destabilization of the maternal centrosome is not due to the complete loss of its centrioles. Together, these results demonstrate that all maternal centrosomes are equivalent and that they are intrinsically different from the paternal centrosome. This intrinsic difference, in concert with a change in cytoplasmic conditions after meiosis, determines the selective loss of the maternal centrosome inherited from the meiosis II spindle.
成熟卵子从第二次减数分裂纺锤体继承一个中心体，而精子在受精时引入第二个中心体。由于这些中心体中只有一个能存活下来用于胚胎发育，所以必然存在特定机制来控制中心体的继承。为了研究中心体继承是如何被控制的，我们以海星卵作为模型系统，因为它们在受精后进行减数分裂。因此，通过光学显微镜可以追踪母本和父本中心体的命运，并且可以在体内进行实验操作。我们首先表明，在海星受精卵发育过程中只有父本中心体被利用；从减数分裂II保留下来的母本中心体在第一次有丝分裂之前功能丧失。然后我们测试了合子对最初存在于同一细胞质中的中心体稳定性进行这种差异控制的多种可能方式。这些实验结果可总结如下：（1）尽管母本中心体的微管组织中心活性在减数分裂后没有被降解，但该中心体在连续有丝分裂时加倍的能力丧失了。（2）精子中心体不会被减数分裂期间或之后可能使所有中心体不稳定的细胞质条件“掩盖”。（3）母本中心体的功能丧失不是由于其皮质定位。（4）这种加倍能力的丧失是由卵子决定的，而不是由来自受精精子的假定抑制因子决定的。（5）母本中心体的不稳定不是由于其中心粒的完全丧失。总之，这些结果表明所有母本中心体都是等同的，并且它们在本质上与父本中心体不同。这种本质差异，与减数分裂后细胞质条件的变化一起，决定了从减数分裂II纺锤体继承的母本中心体的选择性丧失。
