Meeting Abstract

P3.71  Jan. 6  Spinal cord protein expression is conserved among gymnotiform fishes during adult regeneration. ALBERT, Sara/H*; KATIRA, Kristopher; ALBERT, James/S; UNGUEZ, Graciela/A; Univ. of Louisiana, Lafayette; Univ. of Louisiana, Lafayette; Univ. of Louisiana, Lafayette; New Mexico State University, Las Cruces salbert@louisiana.edu

Gymnotiforms and urodeles are unique among vertebrates in their capacity to regenerate most tissue-types after tail amputation, including spinal cord. Data from urodeles indicate that dedifferentiation of mature cells gives rise to the regeneration blastema (Nye et al., 2003), whereas regeneration studies in the gymnotiform Sternopygus macrurus suggest that stem cells are a major source of blastemal cells (Patterson and Zakon, 1993; Weber and Unguez, 2005). Given that in gymnotiforms the ependyma (i.e., the layer of ciliated epithelial cells lining the spinal cord central canal) forms early within the blastema, we hypothesize that signals from the spinal cord are important in blastema formation. Hence, we have begun to characterize markers of ependymal cells (cytokeratin 8 and vimentin), neuronal precursors (engrailed, Islet 1/2, Pax7, Sox1/2 and Shh), and mature neurons (HuC, SV-2) in adult tails and 2-week blastemas of S. macrurus, Eigenmania virescens and Gymnotus javari. We have detected labeling by antibodies against cytokeratin 8, vimentin, engrailed, Sox1/2 and Shh in cells around the central canal in blastema and adult spinal cords. In contrast, antibodies against Pax7, HuC and SV2 show distinct labeling patterns in adult spinal cord neurons. Further characterization of distinct cell populations by immunohistochemistry, EM, BrdU labeling and tracing studies will allow a more complete identification of correlates of regeneration mechanisms in teleosts. Supported by NSF DEB 0614334 (JSA) and NIH grants RR16480 and S06-GMO8136 (GAU).