SIZE-CONTROL IN THE CHLAMYDOMONAS-REINHARDTII FLAGELLUM
SIZE-CONTROL IN THE CHLAMYDOMONAS-REINHARDTII FLAGELLUM
复制标题
DOI：
10.1111/j.1550-7408.1988.tb04154.x
复制
发表时间：
1988-11-01
期刊：
影响因子：
--
通讯作者：
JARVIK, JW
中科院分区：
文献类型：
--
作者：
JARVIK, JW
IZE是任何生物体的基本属性，因此理解生物尺寸控制的现象学和分子机制是很有意义的。当然，对于原生动物来说，控制生物体的大小与控制细胞的大小是一样的，但值得注意的是，后生动物的生物体的大小会受到其组成细胞的大小的非常显著的影响。因此，例如，脊椎动物出生后的大小增加的大部分是由细胞大小而不是细胞数量的增加引起的。对于增殖的细胞，大小可以通过有丝分裂和细胞分裂的方式来调节，这对细胞大小很敏感，并且存在大量实验证据支持这种观点。然而，细胞能够感知自身大小的机制的本质仍然是个谜。包括我在内的一些生物学家决定从细胞整体的角度来研究纤毛和鞭毛的大小控制，而不是试图从细胞整体的角度来分析大小控制。这些细胞器的大小控制机制是否与整个细胞的大小控制机制相似还有待观察，但在任何情况下，鞭毛的大小控制对我们来说似乎是一个更容易处理的问题，也是一个有趣的问题。纤毛和鞭毛的长度通常受到高度调节，其值对生物体或细胞类型具有特异性，并且在许多情况下，甚至对细胞表面上的特定位置具有特异性。因此，鞭毛长度受细胞控制是肯定的，正如下文将要讨论的鞭毛长度突变体的存在所证明的那样，同样可以说鞭毛长度受遗传控制。鉴于这些事实，我们不难发现，生物体已经进化到拥有纤毛和鞭毛，其长度特别适合于它们所发挥的特定细胞和器官作用。
IZE is a fundamental property of any organism, and so it is S of interest to understand the phenomenology and the molecular mechanisms of biological size-control. For a protozoon, of course, size-control for the organism is the same as sizecontrol for the cell, but it is worth noting that the size of a metazoan organism can be very significantly influenced by the sizes of its constituent cells. Thus, for example, a large fraction of the increase in the size of a vertebrate animal after birth is accounted for by increases in cell size rather than cell numbers. For proliferating cells, size can be regulated by means of a commitment to mitosis and cell division which is sensitive to cell size, and there exists a large body of experimental evidence in favor of such a notion. The nature of the mechanism by which a cell can sense its own size, however, remains mysterious. Rather than attempting to analyze size-control at the level of the cell as a whole, a few biologists, myself included, have decided to examine size-control for cilia and flagella. Whether the mechanism of size-control for these organelles bears a resemblance to the mechanism of size-control for the entire cell remains to be seen, but in any case flagellar size-control seems to us to be a more tractable problem-as well as one which is interesting in and of itself. Ciliary and flagellar lengths are generally highly regulated, with values specific to the organism or cell type and, in many instances, even specific to particular locations on the cell surface. It must be true then that flagellar length is under cellular control, and, as demonstrated by the existence of the flagellar length mutants to be discussed in the paragraphs to follow, it can equally well be said that flagellar length is under genetic control. In view of these facts, it is hardly surprising to find that organisms have evolved to possess cilia and flagella whose lengths are especially well suited to the specific cellular and organismic roles they serve.