title: The TunicateCIONA: A Model System for Understanding the Relationship Between Regeneration and Aging.
abstract: The use of the tunicateCiona intestinalisas a model system to study the relationship between regeneration and aging is reviewed.Cionahas powerful regeneration capacities, which fade with age. Some additional benefits are-, a relatively short life span, the ability to study regenerationin vitro, the close phylogenetic relationship between tunicates and vertebrates, and the host of molecular tools already established in this system. The neural complex (NC), the oral siphon (OS), and the oral siphon pigment organs (OPO) have high capacities for regeneration. However, these organs show an inverse relationship between rate of regeneration and age. The ability to regenerate a complete OS disappears in the oldest animals of a natural population, probably due to the inability to form a blastema at the wound site. Effects on blastema formation could also be involved in the reduction of NC regeneration capacity. The fidelity of OPO restoration is also compromised by excess differentiation of precursor cells in local siphon niches in the oldest animals. TheCionamodel provides a pathway to understand the molecular basis of these phenomena.
authors.affiliation: Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA 02543 USA.
authors.forename: William R
authors.initials: WR
authors.lastname: Jeffery
keywords: Ciona intestinalis; neural complex; oral siphon; oral siphon sensory organs