Identification of a meristem L1 layer-specific gene in Arabidopsis that is expressed during embryonic pattern formation and defines a new class of homeobox genes
Identification of a meristem L1 layer-specific gene in Arabidopsis that is expressed during embryonic pattern formation and defines a new class of homeobox genes
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DOI：
10.1105/tpc.8.12.2155
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发表时间：
1996-12-01
期刊：
影响因子：
11.6
通讯作者：
ONeill, SD
中科院分区：
文献类型：
--
作者：
Lu, PZ;Porat, R;ONeill, SD
同源异型盒基因是许多真核生物包括植物的主要调控基因，它决定着生物体的生长和发育。（用于拟南芥分生组织L1层），其编码新的同源结构域蛋白，ATML 1蛋白与蝴蝶兰O39和拟南芥GLABRA 2（GL 2）在同源结构域内部和外部都具有高度的序列同源性。同源结构域蛋白，它们一起定义了一类新的含植物同源结构域的蛋白，命名为HD-GLS。ATML 1基因首先在合子第一次不对称分裂后的顶端细胞中表达，并在所有原胚细胞中持续表达，直到8细胞期。在16细胞原胚中，ATML 1基因显示出独特的表达模式，其mRNA变得仅限于原胚层。ATML 1 mRNA完全消失，但随后仅在成熟胚的茎顶端分生组织的L1层中重新出现。萌发后，这种L1层特异性表达模式在营养枝顶端分生组织、花序和花分生组织中保持，最后，ATML 1 mRNA在胚珠原基和珠被的原皮层中积累，并逐渐限制在胚囊周围的内皮中表达。我们认为，ATML 1可能参与了控制细胞特化和图案形成所必需的位置信息的形态发生边界的建立。此外，ATML 1为植物胚胎发生过程中建立顶基和径向模式提供了早期分子标记。
Homeobox genes are master regulatory genes that specify the body plan and control development of many eukaryotic organisms, including plants, We isolated and characterized a cDNA designated ATML1 (for Arabidopsis thaliana meristem L1 layer) that encodes a novel homeodomain protein, The ATML1 protein shares high sequence homology inside and outside of the homeodomain with both the Phalaenopsis O39 and the Arabidopsis GLABRA2 (GL2) homeodomain proteins, which together define a new class of plant homeodomain-containing proteins, designated HD-GLS. The ATML1 gene was first expressed in the apical cell after the first asymmetric division of the zygote and continued to be expressed in all proembryo cells until the eight-cell stage, In the 16-cell proembryo, the ATML1 gene showed a distinct pattern of expression, with its mRNA becoming restricted to the protoderm, In the torpedo stage of embryo development, ATML1 mRNA disappeared altogether but reappeared later only in the L1 layer of the shoot apical meristem in the mature embryo, After germination, this L1 layer-specific pattern of expression was maintained in the vegetative shoot apical meristem, inflorescence, and floral meristems, as well as in the young floral organ primordia, Finally, ATML1 mRNA accumulated in the protoderm of the ovule primordia and integuments and gradually became restricted in its expression to the endothelium surrounding the embryo sac, We propose that ATML1 may be involved in setting up morphogenetic boundaries of positional information necessary for controlling cell specification and pattern formation, In addition, ATML1 provides an early molecular marker for the establishment of both apical-basal and radial patterns during plant embryogenesis.