Ford C C
J Embryol Exp Morphol. 1985 Nov;89 Suppl:271-84.
Cell cycles in early amphibian embryos are characterized by the absence of G1 and G2 phases. The simple cycle of S phase and mitosis does show similarities with other systems, particularly in the presence of cytoplasmic components advancing nuclei into DNA synthesis and mitosis. Maturation-promoting factor induces nuclear envelope breakdown and subsequent chromosome condensation. Cytoplasmic factors appear during maturation which are capable of inducing DNA synthesis, and arrest of the nuclear division cycle in metaphase (cytostatic factor). The timing of appearance of these activities is considered and their relationship in integrating DNA synthesis during early cleavage is discussed.
早期两栖类胚胎中的细胞周期特点是没有G1期和G2期。S期和有丝分裂的简单周期确实与其他系统存在相似之处，尤其是存在促使细胞核进入DNA合成和有丝分裂的细胞质成分。成熟促进因子诱导核膜破裂及随后的染色体凝聚。成熟过程中会出现能够诱导DNA合成并使核分裂周期停滞在中期的细胞质因子（细胞静止因子）。本文探讨了这些活性出现的时间，并讨论了它们在早期卵裂过程中整合DNA合成方面的关系。
