THE KINETOCHORES OF CAENORHABDITIS-ELEGANS
THE KINETOCHORES OF CAENORHABDITIS-ELEGANS
复制标题
DOI：
10.1007/bf00292267
复制
发表时间：
1982-01-01
期刊：
影响因子：
1.6
通讯作者：
THOMSON, JN
中科院分区：
文献类型：
--
作者：
ALBERTSON, DG;THOMSON, JN
光学显微镜下观察到了C. elegans提出，存在非定位的动粒，因为染色体表现为长度为1-2 μ m的硬杆，并且没有任何可见的收缩。全动力学结构证实了连续切片胚胎分裂核的EM重建。在前期，动粒在横截面上表现为直径约0.18-0.2 μ m的无定形突起，在纵截面上，它沿染色质沿着是连续的。在前中期和中期，动粒是覆盖在染色体极向面上并延伸染色体长度的凸斑。在纵截面中，动粒是具有0.02 μ m的电子致密内层和外层以及0.02 μ m的电子透明中间层的三层结构。内层与染色质的电子密度更高的区域相邻。在乙醇磷钨酸染色的整条染色体标本中，动粒也被看作是延长染色体长度的条带。大多数γ。射线诱导的染色体片段在胚胎有丝分裂中正常分离，但有些片段表现出异常行为。类似的行为在携带遗传特征的自由复制的胚胎中也观察到。小片段的有丝分裂分离可能是无效的，因为微管附着于动粒的概率与动粒长度成正比。
Light microscopy of the mitotic chromosomes of C. elegans suggests that non-localized kinetochores are present, since the chromosomes appear as stiff rods 1-2 .mu.m in length and lack any visible constriction. The holokinetic structure was confirmed by reconstructions of EM of dividing nuclei in serially sectioned embryos. In prophase the kinetochore appears as an amorphous projection approximately 0.18-0.2 .mu.m in diameter in cross section and in longitudinal section it appears to be continuous along the chromatin. At prometaphase and metaphase, the kinetochore is a convex plaque covering the poleward face of the chromosome and extending the length of the chromosome. In longitudinal section, the kinetochore is a trilaminar structure with electron dense inner and outer layers of 0.02 .mu.m, and an electron lucent middle layer of 0.02 .mu.m. The inner layer is adjacent to a more electron dense region of chromatin. The kinetochore was also seen as a band extending the length of the chromosome in whole mount preparations of chromosomes stained with ethanolic phosphotungstic acid. Most .gamma. ray-induced chromosome fragments segregate normally in embryonic mitoses, but some fragments display aberrant behavior. Similar behavior was seen in embryos carrying a genetically characterized free duplication. Mitotic segregation of small fragments may be inefficient because the probability of attachment of microtubules to the kinetochore is proportional to kinetochore length.