Kovacech B, Nasmyth K, Schuster T
Institute of Medical Radiation and Cell Research, University of Würzburg, Germany.
Mol Cell Biol. 1996 Jul;16(7):3264-74. doi: 10.1128/MCB.16.7.3264.
In a screen for cell cycle-regulated genes in the yeast Saccharomyces cerevisiae, we have identified a gene, EGT2, which is involved in cell separation in the G1 stage of the cell cycle. Transcription of EGT2 is tightly regulated in a cell cycle-dependent manner. Transcriptional levels peak at the boundary of mitosis and early G1 The transcription factors responsible for EGT2 expression in early G1 are Swi5 and, to a lesser extent, Ace2. Swi5 is involved in the transcriptional activation of the HO gene during late G1 and early S phase, and Ace2 induces CTS1 transcription during early and late G1 We show that Swi5 activates EGT2 transcription as soon as it enters the nucleus at the end of mitosis in a concentration-dependent manner. Since Swi5 is unstable in the nucleus, its level drops rapidly, causing termination of EGT2 transcription before cells are committed to the next cell cycle. However, Swi5 is still able to activate transcription of HO in late G1 in conjunction with additional activators such as Swi4 and Swi6.
在对酿酒酵母细胞周期调控基因的筛选中，我们鉴定出了一个基因EGT2，它参与细胞周期G1期的细胞分离过程。EGT2的转录以细胞周期依赖性方式受到严格调控。转录水平在有丝分裂和早期G1期的边界达到峰值。在早期G1期负责EGT2表达的转录因子是Swi5，其次是Ace2。Swi5在G1晚期和S期早期参与HO基因的转录激活，而Ace2在G1早期和晚期诱导CTS1转录。我们发现，Swi5在有丝分裂末期进入细胞核后，会以浓度依赖性方式立即激活EGT2转录。由于Swi5在细胞核中不稳定，其水平迅速下降，导致EGT2转录在细胞进入下一个细胞周期之前终止。然而，Swi5在G1晚期仍能与其他激活因子（如Swi4和Swi6）一起激活HO的转录。
