Soares Helena, Carmona Bruno, Nolasco Sofia, Viseu Melo Luís
Centro de Química e Bioquímica/Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal.
Escola Superior de Tecnologia da Saúde de Lisboa, Instituto Politécnico de Lisboa, Lisbon, Portugal.
Front Cell Dev Biol. 2019 Oct 18;7:240. doi: 10.3389/fcell.2019.00240. eCollection 2019.
and are highly differentiated unicellular organisms with elaborated cortical patterns showing a regular arrangement of hundreds to thousands of basal bodies in longitudinal rows that extend from the anterior to the posterior region of the cell. Thus both ciliates exhibit a permanent antero-posterior axis and left-right asymmetry. This cell polarity is reflected in the direction of the structures nucleated around each basal body such as the ciliary rootlets. Studies in these ciliates showed that basal bodies assemble two types of cilia, the cortical cilia and the cilia of the oral apparatus, a complex structure specialized in food capture. These two cilia types display structural differences at their tip domain. Basal bodies possessing distinct compositions creating specialized landmarks are also present. Cilia might be expected to express and transmit polarities throughout signaling pathways given their recognized role in signal transduction. This review will focus on how local polarities in basal bodies/cilia are regulated and transmitted through cell division in order to maintain the global polarity and shape of these cells and locally constrain the interpretation of signals by different cilia. We will also discuss ciliates as excellent biological models to study development and morphogenetic mechanisms and their relationship with cilia diversity and function in metazoans.
纤毛虫是高度分化的单细胞生物，具有复杂的皮层模式，显示出数百到数千个基体在纵向排列成行，从细胞的前部延伸到后部。因此，这两种纤毛虫都表现出永久的前后轴和左右不对称性。这种细胞极性反映在围绕每个基体形成的结构（如纤毛小根）的方向上。对这些纤毛虫的研究表明，基体组装两种类型的纤毛，即皮层纤毛和口器纤毛，口器是专门用于捕获食物的复杂结构。这两种纤毛类型在其顶端区域表现出结构差异。还存在具有不同组成并形成特殊标记的基体。鉴于纤毛在信号转导中的公认作用，预计纤毛会在整个信号通路中表达和传递极性。本综述将重点关注基体/纤毛中的局部极性如何通过细胞分裂进行调节和传递，以维持这些细胞的整体极性和形状，并局部限制不同纤毛对信号的解读。我们还将讨论纤毛虫作为研究发育和形态发生机制以及它们与后生动物中纤毛多样性和功能关系的优秀生物学模型。
