Meeting Abstract

S3.3-1  Saturday, Jan. 4 13:30  Using live imaging to probe the cellular basis of annelid regeneration BELY, A. E.*; ZATTARA, E. E.; LI, A.; University of Maryland, College Park; University of Maryland, College Park; University of Maryland, College Park abely@umd.edu

Regeneration, the ability to replace lost body parts, is widespread among animals yet its cellular and molecular basis is poorly understood in all but a few species. Such knowledge gaps severely limit our understanding of the evolution of regeneration. A fundamental challenge to studying the cellular basis of regeneration is that the process typically takes place in moving adult organisms, over long periods of time (days to weeks), and in dense tissues, making it difficult to discern even basic morphogenetic and cellular processes in many groups. We are studying regeneration in annelids (segmented worms), focusing in particular on identifying the cells that are activated following injury and participate in regeneration. Toward this end, we have developed a method for long-duration time-lapse imaging of regeneration, using a selective neurotoxin to immobilize specimens. Using this technique, we can continuously image the entire regeneration process in several species of naidid annelids, a group of small, largely transparent worms. Our ongoing studies indicate that injury triggers a major cell migration response, with large numbers of cells with different morphologies and migration speeds moving both toward and away from the wound site. One type of migratory cell corresponds to a cell type (the neoblast) that has long been suspected of being involved in initiating regeneration and/or providing source cells for regenerated structures in annelids. Ongoing studies are aimed at comparing the cell migration response in regenerative and non-regenerative contexts to identify features of cell migration characteristic of successful regeneration. Ultimately, comparisons of the cellular basis of regeneration in a range of animals will be key to understanding how regeneration has evolved, how it has diversified, and why it fails.