Cell cycle regulation of cyclin-dependent kinases in tobacco cultivar Bright Yellow-2 cells.
Cell cycle regulation of cyclin-dependent kinases in tobacco cultivar Bright Yellow-2 cells.
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DOI：
10.1104/pp.126.3.1214
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发表时间：
2001-07
期刊：
影响因子：
7.4
通讯作者：
D. Sorrell;M. Menges;J. M. Healy;Y. Deveaux;C. Amano;Ya Su;Hirofumi;Nakagami;A. Shinmyō;J. Doonan;M. Sekine;J. Murray
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文献类型：
--
作者：
D. Sorrell;M. Menges;J. M. Healy;Y. Deveaux;C. Amano;Ya Su;Hirofumi;Nakagami;A. Shinmyō;J. Doonan;M. Sekine;J. Murray
植物具有两大类细胞周期蛋白依赖性激酶（CDK），其具有细胞周期蛋白结合基序PSTAIRE（CDK-a）和PPTA/TLRE（CDK-b）。烟草（Nicotiana tabacum L.）cv Bright Yellow-2）细胞是最高度同步化的植物培养物，但在该系统中没有详细的CDK活性分析的报道。在这里，我们描述了新的PPTALRE CDKs（尼克塔; CdkB 1）从亮黄-2细胞的分离，并提出了详细的分析的mRNA，蛋白质和激酶活性水平的CdkB 1，和PSTAIRE CDKA在生长和细胞周期。CdkA和CdkB 1转录物在指数期细胞中比在稳定期细胞中更丰富，但这两个基因在细胞周期中显示出显著不同的调控。CdkA的mRNA和蛋白质积累在G1期细胞重新进入细胞周期，和免疫沉淀组蛋白H1激酶活性增加在G1/S边界。Aphidicolin同步化的细胞在S-G2期显示出最高的CDKA相关组蛋白H1激酶活性，尽管CdkA mRNA和蛋白水平没有显著调节。与此相反，CdkB 1转录本是在非常低的水平，直到S期和CDKB 1蛋白和激酶活性几乎是不可检测的G1。CdkB 1 mRNA通过S期直至M期积累，其相关激酶活性在G2/M边界达到峰值，证实PPTALRE CDKs的转录受细胞周期调节。我们认为CDKA激酶活性可能在G1/S期边界、S期和G2/M期转变中起作用，而CDKB 1激酶活性仅存在于G2/M期。
Plants possess two major classes of cyclin-dependent kinases (CDK) with cyclin-binding motifs PSTAIRE (CDK-a) and PPTA/TLRE (CDK-b). Tobacco (Nicotiana tabacum L. cv Bright Yellow-2) cells are the most highly synchronizable plant culture, but no detailed analysis of CDK activities has been reported in this system. Here we describe isolation of new PPTALRE CDKs (Nicta;CdkB1) from Bright Yellow-2 cells and present detailed analysis of the mRNA, protein and kinase activity levels of CdkB1, and the PSTAIRE CDKA during the growth and cell cycles. CdkA and CdkB1 transcripts are more abundant in exponential than in stationary phase cells, but the two genes show strikingly different regulation during the cell cycle. CdkA mRNA and protein accumulate during G1 in cells re-entering the cell cycle, and immunoprecipitated histone H1 kinase activity increases at the G1/S boundary. Aphidicolin synchronized cells show the highest CDKA-associated histone H1 kinase activity during S-G2 phases, although CdkA mRNA and protein levels are not significantly regulated. In contrast, CdkB1 transcripts are present at very low levels until S phase and CDKB1 protein and kinase activity is almost undetectable in G1. CdkB1 mRNA accumulates through S until M phase and its associated kinase activity peaks at the G2/M boundary, confirming that transcription of PPTALRE CDKs is cell cycle regulated. We suggest that CDKA kinase activity likely plays roles at the G1/S phase boundary, during S phase, and at the G2/M phase transition, and that CDKB1 kinase activity is present only at G2/M.