Miake-Lye R, Newport J, Kirschner M
J Cell Biol. 1983 Jul;97(1):81-91. doi: 10.1083/jcb.97.1.81.
We have studied the effect of maturation-promoting factor (MPF) on embryonic nuclei during the early cleavage stage of Xenopus laevis development. When protein synthesis is inhibited by cycloheximide during this stage, the embryonic cell cycle arrests in an artificially produced G2 phase-like state, after completion of one additional round of DNA synthesis. Approximately 100 nuclei can be arrested in a common cytoplasm if cytokinesis is first inhibited by cytochalasin B. Within 5 min after injection of MPF into such embryos, the nuclear envelope surrounding each nucleus disperses, as determined histologically or by immunofluorescent staining of the nuclear lamina with antilamin antiserum. The breakdown of the nuclear envelope occurs at levels of MPF comparable to or slightly lower than those required for oocyte maturation. Amplification of MPF activity, however, does not occur in the arrested egg as it does in the oocyte. These results suggest that MPF can act to advance interphase nuclei into the first events of mitosis and show that the nuclear lamina responds rapidly to MPF.
我们研究了成熟促进因子（MPF）对非洲爪蟾发育早期卵裂阶段胚胎细胞核的影响。在此阶段，当用放线菌酮抑制蛋白质合成时，胚胎细胞周期在额外完成一轮DNA合成后，会停滞在人为产生的类似G2期的状态。如果先用细胞松弛素B抑制胞质分裂，大约100个细胞核可以被阻滞在共同的细胞质中。将MPF注射到此类胚胎中5分钟内，通过组织学检查或用抗核纤层蛋白抗血清对核纤层进行免疫荧光染色确定，每个细胞核周围的核膜都会分散。核膜的破裂发生时MPF的水平与卵母细胞成熟所需的水平相当或略低。然而，与卵母细胞不同，在停滞的卵中不会发生MPF活性的放大。这些结果表明，MPF可以促使间期细胞核进入有丝分裂的最初阶段，并表明核纤层对MPF反应迅速。
