Relationship between nuclear DNA synthesis and centrosome reproduction in sea urchin eggs.
Relationship between nuclear DNA synthesis and centrosome reproduction in sea urchin eggs.
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海胆卵核DNA合成与中心体繁殖的关系。
DOI：
10.1002/jez.1402440111
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发表时间：
1987
期刊：
影响因子：
--
通讯作者：
Lewis,K
中科院分区：
文献类型：
--
作者：
Sluder,G;Lewis,K
在不受生长限制的细胞中，例如海胆卵，核DNA合成对于中心体加倍或繁殖的重要性还没有明确定义。对去核受精卵的研究表明，完整中心体的正常繁殖并不需要每个细胞周期的核活动。然而，其他研究报告说，药物aphidiclin抑制完整鸡蛋中的核DNA合成，阻止中心体繁殖和进入有丝分裂，如核膜破裂所见。为了解决这一悖论，我们系统地表征了APHIDICOIN对三种海胆卵细胞分裂的影响。受精后5min开始用5或10μg/mlAphidicolin连续处理卵子。正如先前报道的那样，这阻止了~3H-胸腺嘧啶核苷进入DNA的总掺入至少90%。我们发现，在第一次有丝分裂之前，精子母细胞总是加倍。在几个小时的时间里，中心体以正常的2-4-8-16方式繁殖，周期比正常更长，更不稳定。在每种培养中，都有不同比例的卵子经历核膜破裂。一旦被打破，即使中心体继续增加，核包络也永远不会发生明显的改革。DNA荧光标记显示染色质不凝聚成离散的染色体。无论核膜是否破裂，染色质看起来都像是一团无定形的纤维，伸展在前两个，然后是四个紫锥菊之间。后来，核膜/染色质失去了与部分或全部中心体的联系。在两种药物浓度下，我们的结果对所有鸡蛋都是相同的。因此，核DNA合成不是海胆卵中心体繁殖所必需的。
The importance of nuclear DNA synthesis for the doubling, or reproduction, of centrosomes in cells that are not growth‐limited, such as sea urchin eggs, has not been clearly defined. Studies of enucleated, fertilized eggs show that nuclear activities are not required at each cell cycle for the normal reproduction of the complete centrosome. However, other studies report that the inhibition of nuclear DNA synthesis in intact eggs by the drug aphidicolin prevents centrosome reproduction and entry into mitosis as seen by nuclear envelope breakdown. To resolve this paradox, we systematically characterized the effect of aphidicolin on cell division in eggs from three species of sea urchins. Eggs were continuously treated with 5 or 10 μg/ml aphidicolin starting 5 min after fertilization. This blocked total incorporation of3H‐thymidine into DNA by at least 90%, as previously reported. We found that the sperm aster always doubles prior to first mitosis. Over a period of several hours, the centrosomes reproduce in the normal 2‐4‐8‐16 fashion, with a period that is longer and more variable than normal. In every culture, a variable percentage of the eggs undergoes nuclear envelope breakdown. Once broken down, the nuclear envelope never visibly reforms even though centrosomes continue to double. Fluorescent labeling of DNA revealed that the chromatin does not condense into discrete chromosomes. Whether or not the nuclear envelope breaks down, the chromatin appears as an amorphous mass of fibers stretched between first two and then four asters. Later, the nuclear envelope/chromatin loses its association with some or all centrosomes. Our results were the same for all eggs at both drug concentrations. Thus, nuclear DNA synthesis is not required for centrosome reproduction in sea urchin eggs.
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影响因子：
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