Change in cell morphogenesis is an important feature for proper development of eukaryotes. It is necessary for cell polarity and asymmetry and is essential for asymmetric cell division. RAM/MOR is a conserved signaling network that coordinates cell polarity determinants important for asymmetric cell division and cell polarity establishment. Mo25 is a scaffold protein that acts as a master regulator of the germinal center kinase (GCK) which triggers the downstream signaling of this network. Little is known about RAM/MOR network or Mo25 protein homologs in plants. Here, we provide a glimpse of the evolutionary gene history of Mo25 in green plants. Our data showed that a duplication of Mo25 occurred at the basis of land plants (Embryophyta), forming the groups Mo25A and Mo25B. Further duplication events occurred in other plant lineages and one subgroup of sequences seemed to be rapidly diverging. This subgroup contained an A. thaliana paralog (AtMo25-1) which lacks intron and is expressed in a similar fashion of retrogenes (i.e. low expression levels and narrow expression breadth), suggesting that this paralog was duplicated by retroposition. We also showed that all AtMo25 proteins are structurally similar to each other and to the human homolog, although differences in residues in the interface between human Mo25 and MST3 are observed in the A. thaliana homologs. Expression profile of AtMo25 homologs suggest that they are required at different developmental contexts, possibly interacting with different partners. Finally, we discuss whether Mo25 duplication in Embryophyta could be an evolutionary novelty important for the terrestrial environment conquest and whether the duplicated paralogs are undergoing neo- or subfunctionalization.

中文翻译：

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植物中 Mo25 基因的进化史，RAM/MOR 信号网络的一个组成部分

细胞形态发生的变化是真核生物正常发育的一个重要特征。它对于细胞极性和不对称性是必需的，对于不对称细胞分裂是必不可少的。RAM/MOR 是一个保守的信号网络，它协调对不对称细胞分裂和细胞极性建立很重要的细胞极性决定因素。Mo25 是一种支架蛋白，作为生发中心激酶 (GCK) 的主要调节因子，可触发该网络的下游信号传导。对植物中的 RAM/MOR 网络或 Mo25 蛋白同源物知之甚少。在这里，我们提供了绿色植物中 Mo25 进化基因历史的一瞥。我们的数据显示，在陆生植物（胚胎植物）的基础上发生了重复的 Mo25，形成了 Mo25A 和 Mo25B 组。在其他植物谱系中发生了进一步的重复事件，一个亚组序列似乎正在迅速分化。该亚组包含一个拟南芥旁系同源物 (AtMo25-1)，它缺乏内含子并以类似逆转录基因的方式表达（即低表达水平和窄表达宽度），表明该旁系同源物通过逆位复制。我们还表明所有 AtMo25 蛋白在结构上彼此相似，并且与人类同源物相似，尽管在拟南芥同源物中观察到人类 Mo25 和 MST3 之间界面上的残基差异。AtMo25 同源物的表达谱表明它们在不同的发育环境中是必需的，可能与不同的伙伴相互作用。最后，