Kane R E
Pacific Biomedical Research Center, University of Hawaii, Honolulu 96822.
Dev Biol. 1990 Oct;141(2):330-43. doi: 10.1016/0012-1606(90)90389-z.
The influence of the egg and sperm on the conductance changes at fertilization in the sea urchin were investigated through cross-fertilization of two Hawaiian species, Tripneustes gratilla and Pseudoboletia indiana. The current-voltage (I-V) relation, measured in voltage-clamped eggs at intervals over the period 2-16 min following the rise to a positive membrane potential that signals sperm attachment, differs significantly in the two species. The magnitude of the conductance change depends on the species of the fertilizing sperm in both homologous and heterologous crosses. This supports the hypothesis that currents during this period arise from sperm membrane channels incorporated into the egg at sperm-egg fusion. Measurements of conductance during the first 90 sec, which includes the period of the major inward current correlated with cortical granule breakdown and elevation of the fertilization envelope, showed that the magnitude and timing of the maximum current also differed in the two species. This conductance change presumably involves an activation of egg membrane channels initiated by the sperm and would be expected to be characteristic of the egg species. However, in cross-fertilized eggs the magnitude and timing of the conductance change over this period also depends on the species of the sperm with little identifiable egg contribution, indicating that the fertilizing sperm can modulate the egg response to influence these events.
通过对两种夏威夷海胆物种，即长刺海胆（Tripneustes gratilla）和印第安拟牛肝海胆（Pseudoboletia indiana）进行杂交受精，研究了卵子和精子对海胆受精时电导变化的影响。在膜电位升至正值表明精子附着后的2 - 16分钟内，对电压钳制的卵子进行间隔测量，得到的电流-电压（I-V）关系在这两个物种中存在显著差异。在同源和异源杂交中，电导变化的幅度取决于受精精子的物种。这支持了这样一种假设，即在此期间的电流来自精子-卵子融合时整合到卵子中的精子膜通道。在最初90秒内对电导的测量，其中包括与皮质颗粒破裂和受精膜升高相关的主要内向电流阶段，结果表明最大电流的幅度和时间在这两个物种中也有所不同。这种电导变化可能涉及由精子引发的卵子膜通道的激活，并且预计是卵子物种的特征。然而，在杂交受精的卵子中，这一时期电导变化的幅度和时间也取决于精子的物种，几乎没有可识别的卵子贡献，这表明受精精子可以调节卵子的反应以影响这些事件。
