NUCLEAR ELONGATION AND CYTOKINESIS IN DROSOPHILA-MONTANA
NUCLEAR ELONGATION AND CYTOKINESIS IN DROSOPHILA-MONTANA
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DOI：
10.1016/0012-1606(71)90141-2
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发表时间：
1971-01-01
影响因子：
2.7
通讯作者：
JACOBSON, AG
中科院分区：
文献类型：
--
作者：
FULLILOVE, SL;JACOBSON, AG
我们用延时摄影和电子显微镜研究了果蝇（Drosophila montana）胚胎在细胞胚盘形成过程中的情况。胚盘形成发生在细胞核第12次有丝分裂后不久，在分裂结束时，周围细胞质中的3500个球形细胞核伸长到直径的2.6倍，体积增加了2.4倍。成束的微管，平行于伸长的方向，围绕着伸长的细胞核。我们认为，小管的作用是限制不断扩大的细胞核，使它们伸长而不是变成更大的球体。胞质分裂开始于细胞核的伸长，导致胚胎同时分裂成围绕内部卵黄团的3500个外周细胞。我们观察到一些卵裂沟通过纺锤体形成，但大多数形成在属于相邻核的紫苑之间。这些观察结果支持了Rappaport的观点，即沟的形成是由成对的紫苑与卵表面的相互作用引起的。一些证据表明，存在一个系统的收缩纤维，这可能是负责开沟。我们证明，有缓慢和快速的开沟阶段，我们提出的可能性，有至少两个来源的膜沟生长。
We have used time-lapse cinematography and electron microscopy to studyDrosophila montanaembryos during formation of the cellular blastoderm, which occurs shortly after the twelfth mitotic division of the nuclei.At the end of this division, the 3500 spherical nuclei in the peripheral cytoplasm elongate to 2.6 × their diameter, increasing their volume 2.4-fold. Bundles of microtubules, oriented parallel to the direction of elongation, surround the elongating nuclei. We propose that the tubules serve to constrain the enlarging nuclei so that they elongate rather than becoming larger spheres. Cytokinesis begins as the nuclei elongate, resulting in the simultaneous division of the embryo into 3500 peripheral cells surrounding the internal yolk mass. We observe that some cleavage furrows form through spindles, but most form between asters belonging to adjacent nuclei. These observations support the ideas of Rappaport that furrow initiation results from the interaction of pairs of asters with the egg surface. Some evidence is given for the existence of a system of contractile fibers which may be responsible for furrowing. We demonstrate that there are both slow and fast phases of furrowing, and we present the possibility that there are at least two sources of membrane for furrow growth.