ALFALFA CYCLINS - DIFFERENTIAL EXPRESSION DURING THE CELL-CYCLE AND IN PLANT ORGANS
ALFALFA CYCLINS - DIFFERENTIAL EXPRESSION DURING THE CELL-CYCLE AND IN PLANT ORGANS
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DOI：
10.1105/tpc.4.12.1531
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发表时间：
1992-12-01
期刊：
影响因子：
11.6
通讯作者：
HEBERLEBORS, E
中科院分区：
文献类型：
--
作者：
HIRT, H;MINK, M;HEBERLEBORS, E
真核细胞的分裂是由有丝分裂促进因子介导的，有丝分裂促进因子由CDC2蛋白激酶和多种有丝分裂周期蛋白组成。我们最近从紫花苜蓿中分离到一个cdc2基因。在此，我们报道了从紫花苜蓿中分离到的两个细胞周期蛋白基因--cycMs1和cycMs2。CycMs2基因与B型细胞周期蛋白有最高的相似性。相反，预测的cycMs1基因的氨基酸序列与所有类型的细胞周期蛋白具有相似的同源性(25%至35%)。这两个基因在分裂的悬浮培养细胞中都有表达，但当细胞进入稳定期时就不再表达了。在同步悬浮培养的紫花苜蓿细胞中，cycMs1和cycMs2的mRNAs在G2期和M期的表达最强。CycMs2的转录本仅在G2和M期细胞中发现，这是Cyclin B基因的典型表达模式，而cycMs1则随着G2的开始而出现。这表明紫花苜蓿cycMs1和cycMs2属于不同类别的细胞周期蛋白。在幼叶中，这两个基因都有较高的表达，而在成熟叶中检测不到转录本，这表明这两个细胞周期蛋白基因在mRNA水平上是真正的细胞分裂标记。在其他器官中，发现了这两个周期蛋白基因更复杂的表达模式。
Cell division in eukaryotes is mediated by the action of the mitosis promoting factor, which is composed of the CDC2 protein kinase and one of the various mitotic cyclins. We have recently isolated a cdc2 gene from alfalfa. Here, we report the isolation of two cyclin genes, cycMs1 and cycMs2, from alfalfa. The cycMs2 gene shows highest similarity to type B cyclins. In contrast, the predicted amino acid sequence of the cycMs1 gene shows similar homology scores to cyclins of all types (25 to 35%). Both genes are expressed in dividing suspension cultured cells but cease to be expressed when the cells enter stationary phase. In synchronized alfalfa suspension cultured cells, the mRNAs of cycMs1 and cycMs2 show maximal expression in the G2 and M phases. Transcripts of cycMs2 are found only in late G2 and M phase cells, an expression pattern typical for cyclin B genes, whereas cycMs1 appears with the onset of G2. This pattern indicates that alfalfa cycMs1 and cycMs2 belong to different classes of cyclins. In young leaves, expression of both genes is high, whereas in mature leaves no transcripts can be detected, indicating that the two cyclin genes are true cell division markers at the mRNA level. In other organs, a more complex expression pattern of the two cyclin genes was found.