MITOTIC CHECKPOINT GENES IN BUDDING YEAST AND THE DEPENDENCE OF MITOSIS ON DNA-REPLICATION AND REPAIR
MITOTIC CHECKPOINT GENES IN BUDDING YEAST AND THE DEPENDENCE OF MITOSIS ON DNA-REPLICATION AND REPAIR
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DOI：
10.1101/gad.8.6.652
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发表时间：
1994-03-15
影响因子：
10.5
通讯作者：
HARTWELL, LH
中科院分区：
文献类型：
--
作者：
WEINERT, TA;KISER, GL;HARTWELL, LH
在真核生物中，当染色体复制不完全或受损时，称为检查点的细胞周期控制会导致停滞在 S 或 G2 期。此前，我们在芽殖酵母中证明，RAD9 和 RAD17 是 DNA 损伤后停滞在 G2 期所需的检查点基因。在这里，我们描述了一种遗传策略，该策略确定了在两种途径中发挥作用的四个额外检查点基因。 DNA 损伤后，需要两类基因才能停滞在 G2 期，而当 DNA 复制不完全时，也需要一类基因才能停滞在 S 期。 G2 特异性基因包括 MEC3（用于有丝分裂进入检查点）、RAD9、RAD17 和 RAD24。 S 期和 G2 期途径共有的基因是 MEC1 和 MEC2。 MEC2 基因被证明与 RAD53 基因相同。通过与细胞分裂周期基因 CDC13 的温度敏感等位基因的相互作用来鉴定检查点突变体； cdc13突变体在G2中停滞并在限制温度下存活，而所有cdc13检查点双突变体未能在G2中停滞并在限制温度下迅速死亡。通过将 rad 和 mec 突变等位基因与 10 个 cdc 突变等位基因（在限制温度下停滞在细胞周期的不同阶段）组合，以及 rad 和 mec 突变等位基因对 DNA 损伤剂和羟基脲（一种抑制 DNA 复制的药物）的反应，检查了 RAD 和 MEC 基因的细胞周期作用。我们得出的结论是，芽殖酵母中的检查点由重叠的 S 期和 G2 期途径组成，这些途径对不完整的 DNA 复制和/或 DNA 损伤做出反应，并导致细胞在有丝分裂前停滞。
In eukaryotes a cell-cycle control termed a checkpoint causes arrest in the S or G2 phases when chromosomes are incompletely replicated or damaged. Previously, we showed in budding yeast that RAD9 and RAD17 are checkpoint genes required for arrest in the G2 phase after DNA damage. Here, we describe a genetic strategy that identified four additional checkpoint genes that act in two pathways. Both classes of genes are required for arrest in the G2 phase after DNA damage, and one class of genes is also required for arrest in S phase when DNA replication is incomplete. The G2-specific genes include MEC3 (for mitosis entry checkpoint), RAD9, RAD17, and RAD24. The genes common to both S phase and G2 phase pathways are MEC1 and MEC2. The MEC2 gene proves to be identical to the RAD53 gene. Checkpoint mutants were identified by their interactions with a temperature-sensitive allele of the cell division cycle gene CDC13; cdc13 mutants arrested in G2 and survived at the restrictive temperature, whereas all cdc13 checkpoint double mutants failed to arrest in G2 and died rapidly at the restrictive temperature. The cell-cycle roles of the RAD and MEC genes were examined by combination of rad and mec mutant alleles with 10 cdc mutant alleles that arrest in different stages of the cell cycle at the restrictive temperature and by the response of rad and mec mutant alleles to DNA damaging agents and to hydroxyurea, a drug that inhibits DNA replication. We conclude that the checkpoint in budding yeast consists of overlapping S-phase and G2-phase pathways that respond to incomplete DNA replication and/or DNA damage and cause arrest of cells before mitosis.