摘要
MYB 蛋白质在真核细胞的有机体起重要作用。在植物， R1R2R3 类型 MYB 蛋白质在房间周期控制工作。然而， R2R3 类型 MYB 蛋白质是否也涉及房间部门过程，仍然保持未知。这里，我们报导那 R2R3 类型抄写因素基因， AtMYB59，涉及房间周期前进和根生长的规定。AtMYB59 蛋白质在洋葱的原子核是局部性的表皮的房间并且 transactivation 活动。在酵母房间的 AtMYB59 的表示压制房间增长，和 transformants 与更长的房间有更多的原子核和更高的 aneuploid DNA 内容。在 AtMYB59 的保存领域的变化在酵母细胞生长上废除它的效果。在同步 Arabidopsis 房间暂停， AtMYB59 基因明确地在房间周期前进期间在 S 阶段被表示。表示和 promoter-GUS 分析表明 AtMYB59 基因富有地在根被表示。转基因的植物 overexpressing AtMYB59 更短的根与野类型的植物(Arabidopsis 就职 Col-0 ) 相比，并且在在根尖端的有丝分裂的房间的一半附近在中期。相反地，空变异的 myb59-1 比关口在中期让更长的根和更少有丝分裂的房间，建议那 AtMYB59 可以由扩大有丝分裂的房间的中期禁止根生长。AtMYB59 调整许多下游的基因，包括 CYCB1； 1 基因，可能通过到 MYB 应答的元素的绑定。这些结果在细胞周期规定和植物根生长为 AtMYB59 支持一个角色。
MYB proteins play important roles in eukaryotic organisms. In plants, the R1R2R3-type MYB proteins function in cell cycle control. However, whether the R2R3-type MYB protein is also involved in the cell division process remains unknown. Here, we report that an R2R3-type transcription factor gene, AtMYB59, is involved in the regulation of cell cycle progression and root growth. The AtMYB59 protein is localized in the nuclei of onion epidermal cells and has transactivation activity. Expression of AtMYB59 in yeast cells suppresses cell proliferation, and the transfor- mants have more nuclei and higher anenpioid DNA content with longer cells. Mutation in the conserved domain of AtMYB59 abolishes its effects on yeast cell growth. In synchronized Arabidopsis cell suspensions, the AtMYB59 gene is specifically expressed in the S phase during cell cycle progression. Expression and promoter-GUS analysis reveals that the AtMYB59 gene is abundantly expressed in roots. Transgenic plants overexpressing AtMYB59 have shorter roots compared with wild-type plants （Arabidopsis accession Col-0）, and around half of the mitotic cells in root tips are at metaphase. Conversely, the null mutant myb59-1 has longer roots and fewer mitotic cells at metaphase than Col, suggesting that AtMYB59 may inhibit root growth by extending the metaphase of mitotic cells. AtMYB59 regulates many downstream genes, including the CYCB1;1 gene, probably through binding to MYB-responsive elements. These results support a role forAtMYB59 in cell cycle regulation and plant root growth.
