A Fission Yeast Gene,him1+/dfp1+, Encoding a Regulatory Subunit for Hsk1 Kinase, Plays Essential Roles in S-Phase Initiation as Well as in S-Phase Checkpoint Control and Recovery from DNA Damage
A Fission Yeast Gene,him1+/dfp1+, Encoding a Regulatory Subunit for Hsk1 Kinase, Plays Essential Roles in S-Phase Initiation as Well as in S-Phase Checkpoint Control and Recovery from DNA Damage
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裂殖酵母基因 him1 /dfp1 编码 Hsk1 激酶的调节亚基，在 S 期启动以及 S 期检查点控制和 DNA 损伤恢复中发挥重要作用
DOI：
10.1128/mcb.19.8.5535
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发表时间：
1999
影响因子：
5.3
通讯作者：
H. Masai
中科院分区：
文献类型：
--
作者：
T. Takeda;Keiko Ogino;Etsuko Matsui;M. Cho;H. Kumagai;T. Miyake;Ken‐ichi Arai;H. Masai
酿酒酵母CDC7编码G1/S转化所需的丝氨酸/苏氨酸激酶，其相关激酶存在于裂变酵母以及包括人类在内的高等真核生物中。Cdc7蛋白的激酶活性取决于调控亚基Dbf4， Dbf4也与复制起点相互作用。我们通过与Cdc7激酶的裂变酵母同源物Hsk1的双杂交筛选鉴定出了him1+，并发现它编码Hsk1的一个调控亚基。Him1与Dfp1相同，先前被鉴定为Hsk1的相关分子，与Hsk1结合并刺激其激酶活性，在体外磷酸化催化和调节亚基以及重组MCM2蛋白。him1+在酵母分裂细胞中对DNA复制至关重要，其转录受细胞周期调控，在M期中期至G1后期增加。该蛋白水平在G1期START时较低，在G1/S期边界处升高，并在整个S期维持在高水平。在细胞周期的G1/S到S阶段，以及在核苷酸剥夺引起的早期S期阻滞中，Him1蛋白被过度磷酸化。在cdc7相关激酶的调控亚基中保守的一个基序的缺失，以及在同一基序中存在的三个丝氨酸和苏氨酸残基的丙氨酸替代，导致羟基脲处理通常诱导的检查点调节缺陷。紫外照射和添加甲基甲烷磺酸盐后，丙氨酸突变体也表现出生长迟缓的现象。根据这个结果，数据库搜索表明him1+与rad35+相同。我们的研究结果揭示了Cdc7/ dbf4相关激酶复合物在s期检查点控制以及DNA损伤后的生长恢复中的新功能，以及其在s期起始中的基本功能。
ABSTRACT Saccharomyces cerevisiae CDC7 encodes a serine/threonine kinase required for G1/S transition, and its related kinases are present in fission yeast as well as in higher eukaryotes, including humans. Kinase activity of Cdc7 protein depends on the regulatory subunit, Dbf4, which also interacts with replication origins. We have identified him1+ from two-hybrid screening with Hsk1, a fission yeast homologue of Cdc7 kinase, and showed that it encodes a regulatory subunit of Hsk1. Him1, identical to Dfp1, previously identified as an associated molecule of Hsk1, binds to Hsk1 and stimulates its kinase activity, which phosphorylates both catalytic and regulatory subunits as well as recombinant MCM2 protein in vitro. him1+ is essential for DNA replication in fission yeast cells, and its transcription is cell cycle regulated, increasing at middle M to late G1. The protein level is low at START in G1, increases at the G1/S boundary, and is maintained at a high level throughout S phase. Him1 protein is hyperphosphorylated at G1/S through S during the cell cycle as well as in response to early S-phase arrest induced by nucleotide deprivation. Deletion of one of the motifs conserved in regulatory subunits for Cdc7-related kinases as well as alanine substitution of three serine and threonine residues present in the same motif resulted in a defect in checkpoint regulation normally induced by hydroxyurea treatment. The alanine mutant also showed growth retardation after UV irradiation and the addition of methylmethane sulfonate. In keeping with this result, a database search indicates that him1+ is identical to rad35+ . Our results reveal a novel function of the Cdc7/Dbf4-related kinase complex in S-phase checkpoint control as well as in growth recovery from DNA damage in addition to its predicted essential function in S-phase initiation.
DOI：
10.1073/pnas.94.26.14320
发表时间：
1997-12-23
影响因子：
11.1
作者：
Jiang, W;Hunter, T
通讯作者：
Hunter, T
裂殖酵母 cdc19 基因编码 MCM 复制蛋白家族的成员。
影响因子：
4
作者：
Forsburg,SL;Nurse,P
通讯作者：
Nurse,P
影响因子：
56.9
作者：
Aladjem, MI;Rodewald, LW;Wahl, GM
通讯作者：
Wahl, GM