N-terminal region is required for functions of the HAM family member
N-terminal region is required for functions of the HAM family member
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DOI：
10.1080/15592324.2021.1940001
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发表时间：
2021-06-23
影响因子：
2.9
通讯作者：
Zhou, Yun
中科院分区：
文献类型：
--
作者：
Geng, Yuan;Zhou, Yun
茎分生组织含有干细胞，它们维持陆地植物地上组织的生长和发育。HAIRY MERISTEM（HAM）家族基因编码GRAS结构域转录调控因子，在控制几种开花植物茎分生组织发育和干细胞稳态中起重要作用。与其他GRAS蛋白类似，HAM家族蛋白在陆地植物中的C-末端区域是保守的，包含定义GRAS结构域的特征基序。相比之下，HAM家族蛋白的N-末端区域在序列和长度上显示出实质性的差异。HAM蛋白的保守功能是否需要可变的和发散的N-末端是未知的。我们最近的工作表明，CrHAM -蕨类植物Ceratopteris richardii中的HAM同源物能够取代拟南芥中II型HAM基因的作用，维持已建立的茎顶端分生组织并促进新的干细胞小生境的启动。在这里，我们提供了额外的信息，并表明，CrHAM包含一个更长的N-末端区域相比，拟南芥HAM蛋白，这是保守的不同蕨类HAM同系物。该区域的缺失在很大程度上损害了CrHAM在茎分生组织中替代拟南芥HAM蛋白的功能的能力。这些新的数据与以前的结果一起表明，虽然缺乏来自不同植物谱系的HAM同源物之间的序列保守性，但N-末端对于HAM家族蛋白的保守功能是重要的。
Shoot meristems contain stem cells, and they sustain growth and development of the above-ground tissues in land plants. The HAIRY MERISTEM (HAM) family genes, encoding GRAS-domain transcriptional regulators, play essential roles in the control of shoot meristem development and stem cell homeostasis in several flowering plants. Similar to other GRAS proteins, the C-terminal regions of HAM family proteins across land plants are conserved, containing signature motifs that define the GRAS domain. In contrast, the N-terminal regions of HAM family proteins display substantial divergence in sequence and length. Whether the variable and divergent N-termini are required for the conserved functions of HAM proteins is unknown. Our recent work showed that CrHAM - the HAM homolog in the fern Ceratopteris richardii was able to replace the role of type-II HAM genes in Arabidopsis, maintaining established shoot apical meristems and promoting the initiation of new stem cell niches. Here, we provide additional information and show that CrHAM contains a much longer N-terminal region compared to Arabidopsis HAM proteins, which is conserved among different fern HAM homologs. The deletion of this region largely compromises the ability of CrHAM to replace the function of Arabidopsis HAM proteins in shoot meristems. These new data together with previous results suggest that, although lacking the sequence conservation among HAM homologs from different plant lineages, the N-termini are important for the conserved functions of HAM family proteins.