Cytodifferentiation of hair cells during the development of a basal chordate.

Cytodifferentiation of hair cells during the development of a basal chordate.
Hear Res. 2013 Jul 19;
Authors: Gasparini F, Caicci F, Rigon F, Zaniolo G, Burighel P, Manni L
Abstract
Tunicates are unic animals for studying the origin and evolution of vertebrates because they are considered vertebrates' closest living relatives and share the vertebrate body plan and many specific features. Both possess neural placodes, transient thickenings of the cranial ectoderm that give rise to various types of sensory cells, including axonless secondary mechanoreceptors. In vertebrates, these are represented by the hair cells of the inner ear and the lateral line, which have an apical apparatus typically bearing cilia and stereovilli. In tunicates, they are found in the coronal organ, which is a mechanoreceptor located at the base of the oral siphon along the border of the velum and tentacles and is formed of cells bearing a row of cilia and short microvilli. The coronal organ represents the best candidate homolog for the vertebrate lateral line. To further understand the evolution of secondary sensory cells, we analysed the development and cytodifferentiation of coronal cells in the tunicate ascidian Ciona intestinalis for the first time. Here, coronal sensory cells can be identified as early as larval metamorphosis, before tentacles form, as cells with short cilia and microvilli. Sensory cells gradually differentiate, acquiring hair cell features with mic...

Source: Hearing Research - July 19, 2013 Category: Audiology Authors: Gasparini F, Caicci F, Rigon F, Zaniolo G, Burighel P, Manni L Tags: Hear Res Source Type: research