A CENTRAL ROLE FOR SWI6 IN MODULATING CELL-CYCLE START-SPECIFIC TRANSCRIPTION IN YEAST
A CENTRAL ROLE FOR SWI6 IN MODULATING CELL-CYCLE START-SPECIFIC TRANSCRIPTION IN YEAST
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DOI：
10.1038/357508a0
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发表时间：
1992-06-11
期刊：
影响因子：
64.8
通讯作者：
NASMYTH, K
中科院分区：
文献类型：
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作者：
DIRICK, L;MOLL, T;NASMYTH, K
在酿酒酵母中，大多数参与DNA复制的基因都是在G1晚期瞬时转录的，因为细胞在Start 1进入新的细胞周期。它们的启动子都包含一个或多个版本的8碱基对基序(ACGCGTNA)，包含一个MluI限制酶位点，称为MluI细胞周期框(MCB)2。MCB对于TMP1胸苷合成酶和POL1 DNA聚合酶基因3，4的G1晚期特异转录是必要和充分的。另一种不同的G1晚期特异的8碱基对转录元件称为SCB(CACGAAAA；ref)。5)被一个包含Swi4和Swi6蛋白6，7的因子结合。在这里，我们描述了在TMP1 MCB上体外形成复合体的过程，该MCB包含Swi6蛋白，并且我们建议，一个相对分子质量为120,000(P120)的蛋白质不同于Swi4。由于SCB和MCB的转录在没有Swi6的情况下发生，但它在细胞周期中不再被正确调控。我们认为Swi6是两种不同起始依赖转录因子的重要调节亚基。一个因子(SBF)含有Swi4并与SCB结合，而另一个(MBF)含有p120蛋白并与MCB结合。
MOST genes involved in DNA replication in the yeast Saccharomyces cerevisiae are transcribed transiently during late G1 as cells become committed to a new cell cycle at Start 1. Their promoters all contain one or more versions of an 8-base-pair motif (ACGCGTNA) containing an MluI restriction enzyme site and called the MluI cell-cycle box (MCB) 2. MCBs are both necessary and sufficient for the late G1-specific transcription of the TMP1 thymidylate synthase and POL1 DNA polymerase genes 3,4. A different late G1-specific 8-base-pair transcription element called the SCB (CACGAAAA; ref. 5) is bound by a factor containing the Swi4 and Swi6 proteins 6,7. We describe here the formation in vitro of complexes on TMP1 MCBs that contain the Swi6 protein and, we suggest, a protein of relative molecular mass 120,000 (p120) that is distinct from Swi4. Transcription due to SCBs and MCBs occurs in the absence of Swi6 but it is no longer correctly regulated in the cell cycle. We suggest that Swi6 is an essential regulatory subunit of two different Start-dependent transcription factors. One factor (SBF) contains Swi4 and binds to SCBs, whereas the other (MBF) contains the protein p120 and binds MCBs.