DNA metabolism gene CDC7 from yeast encodes a serine (threonine) protein kinase.
DNA metabolism gene CDC7 from yeast encodes a serine (threonine) protein kinase.
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来自酵母的 DNA 代谢基因 CDC7 编码丝氨酸（苏氨酸）蛋白激酶。
DOI：
10.1073/pnas.87.16.6272
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发表时间：
1990
影响因子：
11.1
通讯作者：
Sclafani,RA
中科院分区：
文献类型：
--
作者：
HollingsworthJr,RE;Sclafani,RA
酵母Cdc 7蛋白是必不可少的启动核DNA复制，基于表型的条件，温度敏感（TS）cdc 7突变体在限制性温度。这种蛋白质同样涉及减数分裂DNA重组和诱导诱变，这可能是由易错DNA修复引起的。我们先前的工作揭示了Cdc 7蛋白和已知蛋白激酶之间的序列相似性。为了确定它是否具有激酶活性，我们已经免疫沉淀的蛋白质从Cdc 7过度生产酵母细胞通过使用多克隆抗体提出了对非变性β-半乳糖苷酶-Cdc 7融合蛋白。在这份报告中，我们证明，Cdc 7免疫复合物能够磷酸化哺乳动物组蛋白H1的丝氨酸和/或苏氨酸残基。来源于在高拷贝数质粒上携带cdc 7 -2 ts突变基因的细胞的免疫复合物具有热不稳定激酶活性。因此，我们推测Cdc 7可能通过磷酸化一种或多种靶底物来调节各种DNA代谢途径。由于Cdc 7激酶在“开始”时作用于Cdc 28/cdc 2激酶功能的下游，因此细胞周期中从G1期到S期的转变可能是蛋白磷酸化级联的结果。
The yeast Cdc7 protein is indispensable to initiation of nuclear DNA replication, based on the phenotype of the conditional, temperature-sensitive (ts) cdc7 mutants at the restrictive temperature. This protein has likewise been implicated in commitment to meiotic DNA recombination and induced mutagenesis, which may result from error-prone DNA repair. Our previous work revealed sequence similarity between the Cdc7 protein and known protein kinases. To determine whether it possesses kinase activity, we have immunoprecipitated the protein from Cdc7-overproducing yeast cells by using polyclonal antibodies raised against a nondenatured beta-galactosidase-Cdc7 fusion protein. In this report, we demonstrate that Cdc7 immune complexes are capable of phosphorylating mammalian histone H1 on serine and/or threonine residues. Immune complexes derived from cells harboring the cdc7-2 ts mutant gene on a high copy number plasmid possess a thermolabile kinase activity. Thus, we postulate that Cdc7 may regulate the various DNA metabolic pathways by phosphorylating one or more target substrates. Because Cdc7 kinase acts downstream of Cdc28/cdc2 kinase function at "start," the transition from G1 to S phase in the cell cycle may be the result of a cascade of protein phosphorylation.