Absence of centrioles and regenerative potential of planaria

A characteristic feature of animal cells is the centrosome, a cytoplasmic organelle that almost always contains a pair of cylindrical centrioles and an organizing matrix of microtubules. Centrosomes are essential for the development of all animal species described so far. Centrioles with centrioles are essential for cells undergoing differentiation—from oocyte division 2-3 to terminal differentiation. The only exceptions are cells that are in the process of regeneration or total regeneration — for example, planarians, hydra, and the like. In planarians, centrioles assemble only in terminally differentiated ciliated cells via the so-called acentriolar pathway to produce cilia assembly. This unique feature allows for the identification of a large set of conserved proteins required for centriole assembly in animals, as well as centrosome-specific proteins absent from the planarian genome. Of particular interest is how irreversible differentiation occurs in acentric planarian cells. Could it be that the centroidless cells of planaria are only capable of modulation?