Molecular mechanisms of regulation of cell division by Myb transcription factors in plants.

植物中 Myb 转录因子调节细胞分裂的分子机制。

基本信息

批准号：
17570032
负责人：
ITO Masaki
金额：
$ 2.3万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17570032/
关键词：
cell cycle plant cell cell proliferation transcriptional regulation Arabidopsis thaliana cytokinesis

项目摘要

Myb transcription factors with three repeats in the Myb domain (3R-Myb) are encoded by a relatively small subfamily in the large Myb gene family in plants. We have previously shown that this type of Myb proteins have important roles in regulation of G2/M-phase genes in tobacco. The 3R-Myb proteins in plants can be divided into 3 classes (A-type, B-type and C-type 3R-Myb) based on their primary sequences. The aim of this research was to elucidate the molecular mechanisms of transcriptional regulation by 3R-Myb and to identify novel factors that regulate activities of 3R-Myb proteins.1. We showed that C-type 3R-Myb proteins act as transcriptional repressors on CYCB1 promoter in tobacco cells.2. The transactivation potential of NtmybA2, a tobacco A-type 3R-Myb protein, is repressed by a regulatory domain located at its C terminus. Deletion of this domain dramatically enhanced its transactivation activity. Our microarray expriments revealed that overexpression of C-terminally deleted version of NtmybA2 resulted in selective upregulation of many G2/M genes that contain MSA elements. The results allowed a genome-wide identification of potential target genes of transcriptianl regulation by NtmybA2 in tobacco cells.3. In another approach, we aimed to identify the mutation that enhances the cytokinesis defect caused by T-DNA insertion mutation of myb3r4, an A-type 3R-Myb gene in Arabidopsis thaliana. We found that one such mutation is present in genome of the wild-type Lansberg. We could map its locus within a 400-kb region located in upper arm of chromosome 3. Further mapping of this locus and complementation experiments would allow us to identify the gene that are responsible for enhancing the cytokinesis defect in myb3r4 background.

Myb 结构域中具有三个重复的 Myb 转录因子 (3R-Myb) 由植物中大型 Myb 基因家族中相对较小的亚家族编码。我们之前已经证明这种类型的 Myb 蛋白在烟草 G2/M 期基因的调节中具有重要作用。植物中的3R-Myb蛋白根据其一级序列可分为3类（A型、B型和C型3R-Myb）。本研究的目的是阐明3R-Myb转录调控的分子机制，并鉴定调节3R-Myb蛋白活性的新因子。1．我们发现C型3R-Myb蛋白在烟草细胞中作为CYCB1启动子的转录抑制因子。2． NtmybA2（一种烟草 A 型 3R-Myb 蛋白）的反式激活潜力受到位于其 C 末端的调节结构域的抑制。该结构域的删除显着增强了其反式激活活性。我们的微阵列实验表明，NtmybA2 C 端缺失版本的过度表达导致许多含有 MSA 元件的 G2/M 基因选择性上调。结果允许在全基因组范围内鉴定烟草细胞中NtmybA2转录调控的潜在靶基因。3．在另一种方法中，我们旨在鉴定增强拟南芥中 A 型 3R-Myb 基因 myb3r4 的 T-DNA 插入突变引起的胞质分裂缺陷的突变。我们发现野生型 Lansberg 的基因组中存在一种这样的突变。我们可以将其基因座定位在位于 3 号染色体上臂的 400 kb 区域内。对该基因座的进一步定位和互补实验将使我们能够识别负责增强 myb3r4 背景中胞质分裂缺陷的基因。