Recruitment of Thr 319-phosphorylated Ndd1p to the FHA domain of Fkh2p requires Clb kinase activity: a mechanism for CLB cluster gene activation
Recruitment of Thr 319-phosphorylated Ndd1p to the FHA domain of Fkh2p requires Clb kinase activity: a mechanism for CLB cluster gene activation
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DOI：
10.1101/gad.1074103
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发表时间：
2003-07-15
影响因子：
10.5
通讯作者：
Dalton, S
中科院分区：
文献类型：
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作者：
Reynolds, D;Shi, BJ;Dalton, S
通过在靶启动子处组装Mcm 1 p-Fkh 2 p复合物来激活CLB基因簇对于有丝分裂进入和通过M期的过渡是必不可少的。我们发现，这种有丝分裂转录程序的激活依赖于Ndd 1 p的招募，Ndd 1 p是一种辅激活因子，通过Fkh 2 p发挥作用来执行其基本功能。虽然NDD 1是一个必需基因，但它在表达缺少C末端的Fkh 2 p截短形式的细胞中被抑制。当在T319上磷酸化时，Ndd 1 p通过与Fkh 2 p的叉头相关（FHA）结构域相关联而被募集到CLB簇启动子。丙氨酸的T319取代显着减少招聘的Ndd 1 p，导致正常的转录调控的损失，细胞生长的严重损害，和一个出芽缺陷，让人联想到细胞与Cdk-Clb激酶缺陷。最后，我们表明，磷酸化的T319和招聘的Ndd 1 p CLB 2和SWI 5启动子依赖于Cdc 28-Clb激酶活性。这些数据提供了一个模型，描述了通过Cdc 28-Clb激酶活性磷酸化Ndd 1 p激活G2/M转录。
Activation of the CLB gene cluster through the assembly of Mcm1p-Fkh2p complexes at target promoters is essential for mitotic entry and transition through M phase. We show that the activation of this mitotic transcriptional program is dependent on the recruitment of Ndd1p, a coactivator that performs its essential function by acting through Fkh2p. Although an essential gene, NDD1 is dispensable in cells expressing a truncated form of Fkh2p lacking its C terminus. When phosphorylated on T319, Ndd1p is recruited to CLB cluster promoters by association with the forkhead-associated (FHA) domain of Fkh2p. Substitution of T319 for alanine significantly reduces recruitment of Ndd1p, resulting in loss of normal transcriptional regulation, severe impairment of cell growth, and a budding defect reminiscent of cells with a Cdk-Clb kinase deficiency. Finally, we show that phosphorylation of T319 and recruitment of Ndd1p to CLB2 and SWI5 promoters is dependent on Cdc28-Clb kinase activity. These data provide a model describing the activation of G2/M transcription through the phosphorylation of Ndd1p by Cdc28-Clb kinase activity.