Osmani S A, Engle D B, Doonan J H, Morris N R
Department of Pharmacology, Robert Wood Johnson Medical School, UMDNJ, Piscataway 08854.
Cell. 1988 Jan 29;52(2):241-51. doi: 10.1016/0092-8674(88)90513-2.
In Aspergillus nidulans the temperature-sensitive cell cycle mutation bimE7 causes chromosome condensation and pre-anaphase spindle formation to occur at restrictive temperature. By constructing double mutants between bimE7 and S phase or G2 phase mutants and blocking DNA replication with hydroxyurea, we demonstrate that bimE7 can cause chromatin condensation and spindle formation in cells held in S or G2. Thus bimE7 overrides normal control systems that prevent mitosis from prematurely occurring during S or G2. We show that bimE7 is a loss of function mutation and propose that bimE normally functions to negatively control a positive mitotic inducing factor, possibly the cell cycle gene nimA.
在构巢曲霉中，温度敏感型细胞周期突变体bimE7在限制温度下会导致染色体凝聚和前后期纺锤体形成。通过构建bimE7与S期或G2期突变体之间的双突变体，并用羟基脲阻断DNA复制，我们证明bimE7可导致处于S期或G2期的细胞发生染色质凝聚和纺锤体形成。因此，bimE7超越了正常的控制系统，这些系统可防止有丝分裂在S期或G2期过早发生。我们表明bimE7是一个功能丧失型突变，并提出bimE通常发挥负调控一个正向有丝分裂诱导因子的作用，该因子可能是细胞周期基因nimA。
