The Arabidopsis Athb-10 (GLABRA2) is an HD-Zip protein required for regulation of root hair development
The Arabidopsis Athb-10 (GLABRA2) is an HD-Zip protein required for regulation of root hair development
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DOI：
10.1046/j.1365-313x.1996.10030393.x
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发表时间：
1996-09-01
期刊：
影响因子：
7.2
通讯作者：
Morelli, G
中科院分区：
文献类型：
--
作者：
Di Cristina, M;Sessa, G;Morelli, G
同源结构域亮氨酸拉链(HD-Zip)蛋白是仅在植物中发现的可能的转录因子。由于同源异型域螺旋-3区序列的保守性，相关的拟南芥同源异型盒基因根据序列相似性分为四个家族。本文报道了属于第四个HD-ZIP家族的747个氨基酸的蛋白AthB-10的特性。研究表明，虽然不那么保守，但在体外DNA结合实验中，AthB-10的亮氨酸拉链可以在功能上取代AthB-2的亮氨酸拉链。基因作图实验和序列比较分析表明，Athb-10与GLABRA2相对应，GLABRA2是参与毛状体发育的同源结构域蛋白。MRMA表达分析表明，Athb-10/GLABRA2不仅在具毛的器官中表达，而且在根中也有表达。对野生型和突变型植株的分析表明，ATSB-10/GLABRA2基因在植株地上部分和根中的表达受到TTG基因突变的影响。对GL2-1突变体的形态分析表明，该基因不仅对毛状体的局部生长是必需的，而且对一组表皮细胞中的根毛发育也是必需的。有趣的是，根毛细胞在通常由非毛细胞占据的位置上的发育取决于GL2-1植物生长的乙烯机制。对GL2-1等位基因的序列分析表明，突变基因编码一个截短的蛋白，该蛋白可能仍然保留部分活性，负责败育毛状体的形成和乙烯依赖的根毛形成调节。
Homeodomain-leucine zipper (HD-Zip) proteins are putative transcription factors identified only in plants. Related Arabidopsis homeobox genes, isolated by virtue of sequence conservation within the helix-3 region of the homeodomain, fall into four families based on sequence similarity. This paper reports the characterization of Athb-10, a 747 amino acid protein belonging to the fourth HD-ZIP family. The studies indicate that, although less conserved, the leucine zipper of Athb-10 can functionally replace that of Athb-2 in an in vitro DNA-binding assay. Gene mapping experiments and sequence comparison analysis revealed that Athb-10 corresponds to GLABRA2, a homeodomain protein involved in trichome development. The mRMA expression analysis revealed that Athb-10/GLABRA2 is expressed not only in trichome-bearing organs, but also in the root. The analysis of wild-type and mutant plants showed that the Athb-10/GLABRA2 gene expression in the aerial part of the plant and in the root is affected by mutations at the TTG locus. Morphological analysis of the gl2-1 mutant revealed that the gene is necessary not only for local outgrowth of the trichome, but also for the regulation of root hair development in a subset of epidermal cells. Interestingly, the development of root hair cells in a position normally occupied by non-hair cells is dependent upon the ethylene regime in which the gl2-1 plants are grown. Sequence analysis of the gl2-1 allele revealed that the mutant gene encodes a truncated protein that might still retain a partial activity responsible for the formation of aborted trichomes and for the ethylene-dependent regulation of root hair formation.