【摘要】 以人工促排的非洲爪蟾卵为材料制备体外无细胞系统,加入Lambda DNA或染色质,用荧光显微镜和电子显微镜观察核的自组装现象.在核的自组装过程中可以看出由丝状、不规则块状到小球状的形态变化,直至形成与真核细胞间期核的形态、结构相似的组装核.在加入染色质时,所观察到的现象和加入Lambda DNA时相似,但形成组装核的过程较快.组装核经过适当浓缩后,以低渗铺展法使其破裂,从核中释放的染色质纤维,电镜观察与细胞核内的染色质有相似之处也有其本身的特点.用蛋白酶处理,纤维变得光滑,其上的颗粒消失;DNase的作用则可使纤维消失,只剩下一些颗粒和片段;RNase处理时没见变化.更多还原

【Abstract】 Using the eggs of Xenopus laevis, we set up an in vitro cell-free system. Under the fluroescent microscope and the electronic microscope, we observed the self-assembly of nuclei when Lambda DNA or chromatin was added to the cell-free system. Right after the adding of Lambda DNA, fibres were observed, then, they changed into irregular blocks, and small spheres, at last, assembled nuclei were formed which had the similar shape and structure to the inter-phase nuclei of eukaryotic cells. A similar but faster process was also observed when chromatin had been added to the system.The assembled nuclei were broken with osmotic shock in order to release their chromatin fibres. The released fibres looked like the chromatin fibres of a cell nucleus in some ways but had their own properties. Treated by protease, the fibres became smoother and the pellets on them disappeared. DNase digestion resulted in the disappearance of fibres, while the pellets and some segments of the fibres still remained. There seemed no effects when the fibres were treated by RNase.更多还原