The Arabidopsis R2R3 MYB proteins FOUR LIPS and MYB88 restrict divisions late in the stomatal cell lineage
The Arabidopsis R2R3 MYB proteins FOUR LIPS and MYB88 restrict divisions late in the stomatal cell lineage
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DOI：
10.1105/tpc.105.034116
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发表时间：
2005-10-01
期刊：
影响因子：
11.6
通讯作者：
Sack, FD
中科院分区：
文献类型：
--
作者：
Lai, LB;Nadeau, JA;Sack, FD
气孔的两个保卫细胞是在终末分化前通过一次对称分裂产生的。四唇（FLP）基因的隐性突变异常诱导至少四个保卫细胞相互接触。这些图案缺陷是由于前体细胞身份的持续存在导致细胞谱系末端的额外对称分裂。FLP可能是从细胞周期到终末分化过渡的正确时机所必需的。FLP编码一个两重复（R2R3）MYB蛋白，其表达在对称分裂前积累。一个旁系同源基因MYB88与FLP功能重叠，产生正常的气孔图案。两个基因突变的纯合植物表现出比单独flp更严重的缺陷，用基因组MYB88构建体转化flp植物恢复野生型表型。这两个基因组成了一个独特的和相对基础的进化枝的非典型R2R3 MYB蛋白，拥有一个不寻常的模式，在其推定的DNA结合域的氨基酸取代。我们的研究结果表明，两个相关的转录因子共同限制分裂晚期拟南芥气孔细胞系。
The two guard cells of a stoma are produced by a single symmetric division just before terminal differentiation. Recessive mutations in the FOUR LIPS (FLP) gene abnormally induce at least four guard cells in contact with one another. These pattern defects result from a persistence of precursor cell identity that leads to extra symmetric divisions at the end of the cell lineage. FLP is likely to be required for the correct timing of the transition from cell cycling to terminal differentiation. FLP encodes a two-repeat (R2R3) MYB protein whose expression accumulates just before the symmetric division. A paralogous gene, MYB88, overlaps with FLP function in generating normal stomatal patterning. Plants homozygous for mutations in both genes exhibit more severe defects than flp alone, and transformation of flp plants with a genomic MYB88 construct restores a wild-type phenotype. Both genes compose a distinct and relatively basal clade of atypical R2R3 MYB proteins that possess an unusual pattern of amino acid substitutions in their putative DNA binding domains. Our results suggest that two related transcription factors jointly restrict divisions late in the Arabidopsis thaliana stomatal cell lineage.