Dahmann C, Futcher B
Cold Spring Harbor Laboratory, New York 11724, USA.
Genetics. 1995 Jul;140(3):957-63. doi: 10.1093/genetics/140.3.957.
The CLB1, CLB2, and CLB3 genes encode B-type cyclins important for mitosis in Saccharomyces cerevisiae, while a fourth B-type cyclin gene, CLB4, has no clear role. The effects of homozygous clb mutations on meiosis were examined. Mutants homozygous for clb1 clb3, or for clb1 clb4, gave high levels of sporulation, but produced mainly two-spored asci instead of four-spored asci. The cells had completed meiosis I but not meiosis II, producing viable diploid ascospores. CLB1 and CLB4 seem to be much more important for meiosis than for mitosis and may play some special role in meiosis II. In contrast, CLB2 is important for mitosis but not meiosis. The level of Cdc28-Clb activity may be important in determining whether meiosis II will occur.
CLB1、CLB2和CLB3基因编码对酿酒酵母有丝分裂很重要的B型细胞周期蛋白，而第四个B型细胞周期蛋白基因CLB4则没有明确作用。研究了纯合clb突变对减数分裂的影响。clb1 clb3或clb1 clb4纯合突变体产生高水平的孢子形成，但主要产生双孢子的子囊而不是四孢子的子囊。细胞完成了减数分裂I但未完成减数分裂II，产生了有活力的二倍体子囊孢子。CLB1和CLB4对减数分裂似乎比对有丝分裂重要得多，可能在减数分裂II中发挥一些特殊作用。相比之下，CLB2对有丝分裂很重要，但对减数分裂不重要。Cdc28-Clb活性水平可能在决定减数分裂II是否会发生方面很重要。
