Meeting Abstract
Echinoderms are well known for their ability to regenerate amputated or autotomized body parts. Regeneration in this phylum is still poorly understood at the mechanistic level. A key part of post-traumatic tissue growth is cell proliferation. Here, we characterized the dynamics of cell division in the regenerating arm of the brittle star Ophioderma brevispinum. Over the 30 day-long observation period, O. brevispinum was able to regrow a significant portion of the autotomized arm. The regenerated arm segments fully restored all anatomical components. The peak of cell proliferation in all arm tissues (epidermis, coelom, radial nerve cord, water vascular canal and the mesenchyme) occurred synchronously on day 5 post-injury. The dynamics of cell division determined by S-phase labeling with EdU corresponds to the temporal pattern of cyclin B expression. We conclude that (a) all anatomical components of the regenerating arm originate from the corresponding tissues of the stump rather than from a set-aside population of multipotent pluripotent cells, (b) there must be a signaling mechanism that synchronizes cell proliferation across the tissues of the regenerating arm.
