JONES K W, ELSDALE T R
J Cell Biol. 1964 May;21(2):245-52. doi: 10.1083/jcb.21.2.245.
Observations have been made of ultrastructural modifications induced in the nuclei of differentiating amphibian embryonic cells cultured in the presence of Actinomycin D. Of particular interest are regions within the nucleus (regions otherwise rather empty) containing loose groupings of uniform threads having a diameter of around 200 A. These threads have been observed in continuous lengths up to 0.5 micro, and appear to be composed of subfilaments. It is suggested, after taking account of some recent work on lampbrush chromosomes, that these threads are lengths of uncoiled chromosome in a condition of heterosynthetic inhibition. It is further suggested that active and inactive portions of the genome may be distinguishable by the facility with which they can be induced to undergo this ultrastructural modification.
已对在放线菌素D存在的情况下培养的两栖类胚胎分化细胞的细胞核中诱导产生的超微结构变化进行了观察。特别令人感兴趣的是细胞核内的一些区域(这些区域在其他情况下相当空旷),其中含有直径约200埃的均匀细丝的松散排列。这些细丝已被观察到连续长度可达0.5微米,并且似乎由亚丝组成。在考虑了最近关于灯刷染色体的一些研究工作之后,有人提出这些细丝是处于异合成抑制状态的解旋染色体片段。进一步有人提出,基因组的活性部分和非活性部分可能通过它们被诱导发生这种超微结构变化的难易程度来区分。