哺乳动物细胞去核产物(胞质体及核体)的结构与功能研究

1967年Carter发现细胞松弛素可以诱发组织培养细胞的自发排核之后,Prescott(1972)借助细胞松弛素存在下的离心处理,使这一排核现象普遍化,从而确立了体外细胞去核的标准方法。经过不断改进(croce et al., 1974;Veomett et al., 1976;Lucas etal., 1976;Wigler et al., 1975),现在,这一技术已广泛应用于细胞学研究的各个重要领域(Mc Burney et al., 1979;Goldman et al., 1974;du Bols et al., 1980)。细胞去核技术及其应用的研究在我国已有初步开展(陈瑞铭等,1979;沈鼎武等,1980)。本实验对二种上皮型传代细胞系进行了去核手术,用扫描电镜和透射电镜对所获得的胞质体

A STUDY OF THE STRUCTURE AND FUNCTION OF CYTOPLASTS AND KARYOPLASTS IN MAMMALIAN CELLS AFTER ENUCLEATION

The surface morphology, fine structure, and physiological activities of the cyto-plast and kayoplast of the HeLa cells which had been enucleated by centrifugation in the presence of cytoehalasin B(CB) were studied.The shape of cytoplasts varied with the different angles of centrifugation. The central part of the cytoplast become slightly thickened, and the microvilli reappeared after removal of CB about one hour later. But in enucleated cells the microvilli with a few branches and thick basal parts found to be less in number than in non-treated cells.The ultrastructure of single eytoplasts was investigated by EM, with modified method of embedding in situ. The cytoplasts contained all kinds of the organelles except the nuclei. The distribution of mitochondria and microfilaments showed remarkable changes. Later on the degenerative changes of mitochondria followed after 8-12 hours. Whereas the number of lysosomes, especially the multivesicular bodies-and the vacuoles increased gradually.Most of the karyoplasts had a normal nuclei, enclosed by a thin layer of cytoplasm and a plasma membrane, while only a few of them had degenerative nuclei without cytoplasm and plasma membrane.On the basis of results obtained from autoradiography, enucleated cells could no longer synthesize DNA or RNA, but might still synthesize proteins, at a rapid decreasing rate. In the karyoplasts of anchorage-dependent mammalian cells, RNA synthesis was interrupted within the initial three hours.The changes in structure as a possible primary cause for the variation of cellular functions are discussed in the text.