Meeting Abstract

71.3  Saturday, Jan. 5  Dynamic Hox gene expression during Capitella teleta juvenile development and posterior regeneration DE JONG, D*; CAVACO, N; SEAVER, E; University of Hawaii, Honolulu; University of Hawaii, Honolulu; University of Hawaii, Honolulu

Hox genes encode transcription factors that play essential roles in anterior-posterior patterning during the development of most metazoans. While most research has concentrated on their involvement in body plan specification during development, their role in regeneration following removal of body segments has only recently begun to be investigated. Capitella teleta, a polychaete annelid, displays spatial and temporal co-linearity of Hox genes in both larval and juvenile stages. Capitella is also able to regenerate posterior segments following amputation and continually generates segments from a posterior growth zone throughout its life. We are investigating the role Hox genes play in these processes. We examined expression of 11 of the 12 known Capitella Hox genes in 14 day juveniles and compared them with previously described expression patterns in 3 day juveniles. At both stages, Hox genes are expressed in the ventral nerve cord ganglia in discrete yet overlapping domains along the anterior-posterior axis. However, a subset of patterns differ between 3d and 14d juveniles. Following amputation of 14d juveniles, certain Hox genes show dynamic expression patterns while the expression of others is unchanged. Expression of Hox genes in regenerating tissue is preceded by onset of cell proliferation and expression of various putative stem cell markers, such as vasa, nanos and piwi. This indicates that following initial proliferation and cell specification of precursors, at least some Hox genes are likely involved in patterning the regenerating ventral nerve cord. These and further investigations will not only reveal the importance of the Hox code in Capitella regeneration, but will also shed light on the evolution of patterning during regeneration.