Cell-to-cell movement of the CAPRICE protein in Arabidopsis root epidermal cell differentiation
Cell-to-cell movement of the CAPRICE protein in Arabidopsis root epidermal cell differentiation
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DOI：
10.1242/dev.02139
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发表时间：
2005-12-01
期刊：
影响因子：
4.6
通讯作者：
Wada, T
中科院分区：
文献类型：
--
作者：
Kurata, T;Ishida, T;Wada, T
CAPRICE（CPC）是一种小的R3型Myb样蛋白，是拟南芥根毛发育的正调控因子。CPC的细胞间运动对于表皮细胞分化为毛母细胞（根毛细胞）是重要的。CPC从其表达的成毛细胞（无毛细胞）转运到成毛细胞，并且通常在其细胞核中积累。使用与GFP融合的CPC的截短版本，我们确定了CPC细胞到细胞运动所必需且足够的信号域。该结构域包括N-末端区域和Myb结构域的一部分。氨基酸取代实验表明，W76和M78在Myb结构域是至关重要的靶向运输，W76是至关重要的CPC：GFP的核积累。为了评估CPC运动的组织特异性，CPC：GFP使用SHR启动子在中柱中表达，使用EGL 3启动子在成毛细胞中表达。CPC：GFP能够从毛原细胞移动到无毛原细胞，但无法从中柱中退出，这表明组织特异性调节因子参与了CPC的细胞间运动。分析与分泌抑制剂，布雷菲德菌素A，并与rhd 3突变体在根表皮分泌过程中的缺陷表明，细胞间CPC运动介导的胞间连丝。此外，CPC与串联GFP的融合定义了CPC增加胞间连丝的尺寸排阻极限的能力。
CAPRICE (CPC), a small, R3-type Myb-like protein, is a positive regulator of root hair development in Arabidopsis. Cell-to-cell movement of CPC is important for the differentiation of epidermal cells into trichoblasts (root hair cells). CPC is transported from atrichoblasts (hairless cells), where it is expressed, to trichoblasts, and generally accumulates in their nuclei. Using truncated versions of CPC fused to GFP, we identified a signal domain that is necessary and sufficient for CPC cell-to-cell movement. This domain includes the N-terminal region and a part of the Myb domain. Amino acid substitution experiments indicated that W76 and M78 in the Myb domain are critical for targeted transport, and that W76 is crucial for the nuclear accumulation of CPC:GFP. To evaluate the tissue-specificity of CPC movement, CPC:GFP was expressed in the stele using the SHR promoter and in trichoblasts using the EGL3 promoter. CPC:GFP was able to move from trichoblasts to atrichoblasts but could not exit from the stele, suggesting the involvement of tissue-specific regulatory factors in the intercellular movement of CPC. Analyses with a secretion inhibitor, Brefeldin A, and with an rhd3 mutant defective in the secretion process in root epidermis suggested that intercellular CPC movement is mediated through plasmodesmata. Furthermore, the fusion of CPC to tandem-GFPs defined the capability of CPC to increase the size exclusion limit of plasmodesmata.