The partitioning of cytoplasmic organelles at cell division.
The partitioning of cytoplasmic organelles at cell division.
复制标题
细胞分裂时细胞质细胞器的分配。
DOI：
10.1016/b978-0-12-364376-6.50009-0
复制
发表时间：
1983
期刊：
影响因子：
--
通讯作者：
BirkyJr,CW
中科院分区：
文献类型：
--
作者：
BirkyJr,CW
当一个生物体的每个细胞只有一个或两个线粒体或叶绿体时，它们的分割很可能总是受到严格的控制，以至于每个子细胞总是接收亲代细胞中一半的细胞器。当细胞器有更多的拷贝时，现有的数据表明，分裂是随机的，但远非随机的，有强烈的平等趋势。促进平均分配的分子机制在任何情况下都是未知的，但细胞器行为的巨大变化表明，不同的生物体涉及许多不同的机制。正如Wilson(1925)指出的那样，细胞质细胞器分裂的精确度很少能与有丝分裂的精确度相提并论，但它仍然是对确保细胞器遗传连续性的机制的选择的表达。细胞如何通过控制细胞器复制来补偿不平等的分割只有一种情况是已知的。但是，当人们考虑到四膜虫和草履虫使用不同的方法来补偿大核DNA的不平等分配时，如果生物也对细胞器使用各种不同的补偿复制模式也就不足为奇了。令人惊讶的是，人们对这些问题的关注如此之少。没有什么比在细胞分裂中对细胞器进行计数更简单的了，但只有两个系统大规模地完成了这项工作。细胞生物学中的定量技术已经发展到即使在细胞器太多而无法直接计数的细胞上也可以进行这样的研究。分配的分子机制几乎没有被触及。关于细胞骨架在决定细胞形状中的作用已经做了很多，也有一些关于它在间期细胞中定位细胞器的作用的观察，但这类研究还没有扩展到细胞分裂。关于微管和微丝在间期细胞周围细胞器运动中的作用，已经进行了一些实验和观察，但还没有关于它们在细胞质分裂时对细胞器的可能作用的研究。这篇文章的主要教训是，我们做的有多少，能做的有多大。细胞质细胞器在细胞分裂过程中的分裂是一个广阔的研究领域，对遗传学和细胞生物学都具有重要意义。
When an organism has only one or two mitochondria or chloroplasts per cell, it is probable that their partitioning is always stringently controlled so that each daughter cell always receives half the organelles in the parent cell. When there are more copies of an organelle, the available data suggest that partitioning is stochastic but far from random, with a strong tendency toward equality. The molecular mechanisms that promote equal partitioning are not known in any case, but the great variety of organelle behavior suggests that many different mechanisms are involved in different organisms. As Wilson (1925) pointed out, the precision of partitioning of cytoplasmic organelles rarely if ever equals that of mitosis, but it is still an expression of selection for mechanisms that will ensure the hereditary continuity of the organelles. How cells compensate for unequal partitioning by controlling organelle replication is known for only one case. But when one considers that Tetrahymena and Paramecium use different methods to compensate for unequal partitioning of macronuclear DNA, it would not be surprising if organisms use a variety of different compensating replication modes for organelles as well. What is surprising is that so little attention has been paid to these problems. Nothing could be simpler than counting organelles in dividing cells, but this has been done on a large scale in only two systems. Quantitative techniques in cell biology have been developed to the point where such studies could be done even on cells that have too many organelles for direct counting. Molecular mechanisms of partitioning have scarcely been touched on. Much more has been done on the role of the cytoskeleton in determining cell shape, and some observations have been made on its role in positioning organelles in interphase cells, but these kinds of studies have not been extended to dividing cells. Some experiments and observations have been made on the role of microtubules and microfilaments in moving cytoplasmic organelles around the cell during interphase, but again nothing has been done on their possible role in partitioning organelles at cytokinesis. The major lesson of this article is how little has been done, and how much can be done. The partitioning of cytoplasmic organelles at cell division is a wide-open field for future research, and one of great importance for both genetics and cell biology.