内耳毛细胞静纤毛高度调控分子机制

内耳毛细胞(hair cell)是动物感知听觉和平衡信息的感受器细胞，负责将机械能信号转换为电信号(即机械-电转换，简称为MET)，因位于其上表面的细胞突起——纤毛束(hair bundle)而得名。每个毛细胞的纤毛束包括一根以微管蛋白为骨架的动纤毛(kinocilium)和多根以肌动蛋白为骨架的静纤毛(stereocilia)。动纤毛在纤毛束的发育过程中发挥重要作用，而静纤毛对于机械-电转换必不可少。每个毛细胞中的静纤毛组织成多排高度不同的阶梯状结构，其发育和维持受到严格调控。近年来，随着蛋白质组学、转录组学、超高分辨显微镜等技术的发展，人们对静纤毛高度调控分子机制的认识越来越深入，但仍有很多问题亟待回答。文章对目前已知的静纤毛高度调控的分子机制进行简要介绍。

Overview on the origin of land plants

The transition of the algal ancestor of land plants from fresh water to land is important in the study of plant evolutionarybiology, which has also changed the terrestrial ecosystem of the earth but the evolutionary mechanism of plant terrestrializationremains unknown. The recent report of high-quality reference genomes of several streptophyte algae and one hornwort sheds light onthis major event. Based on these studies, we can draw the following conclusions: ①Zygnematophyceae was found to be the closestsister group to the common ancestor of land plants found so far; ②The acquisition of GRAS and PYL genes from soil bacteria viahorizontal gene transfer plays an important role in driving the adaptive process of plant terrestrialization; ③The terrestrialization ofplant ancestors is an asymptotic evolutionary process, and the genetic material has gone through a series of pre-adaptation processes,which many gene families previously thought to be unique to land plants exist in more primitive green algae; ④Genomics is animportant method for studying terrestrialization and its reversibility process (such as some aquatic angiosperms). The molecularmechanism of the adaptive process of plant terrestrialization is still one of the current research hotspots, including artificial designof “experimental evolution”, horizontal gene transfer, a natural transgenic engineering event, and its key role in plant evolution andadaptation.