Meeting Abstract
Lumbriculus variegatus is a freshwater annelid that has robust regenerative capabilities. Previous work in our lab has demonstrated that proper head regeneration is a crucial step for downstream mechanisms that mediate functional recovery of behaviors within the original worm fragment. We describe cellular changes occurring at the head blastema and identify proteins that are changed in their expression within the regenerating head and in segments located just behind the head. Experiments removing thirty-segment fragments from either the anterior or posterior region of the worm, demonstrate that the head always regenerates on the anterior end of the fragment, regardless of which position along the body axis the fragment was removed (n=10). This data suggests that polarity of the injured fragment is maintained. However, when worms are amputated at varying positions along the anterior-posterior axis, asexual fission planes form more readily (n=17; 76.5%) in the anterior 1/3 region in comparison to injury within the posterior 2/3 region. Molecular expression in regenerating head segments was characterized using antibodies raised against Drosophila wingless protein and antigens isolated from regenerating blastemal tissue in planaria. The antibody raised against blastemal antigens (1D9-E11) demonstrated the most unique staining patterns in regenerating head and tail tissue with puncta found throughout each region and along the top of the ventral nerve cord. Immunoblots using the 1D9-E11 antibody identified the presence of 3 positive protein epitopes: one that is 126-129KDa, one that is 103-109KDa, and another that is 87KDa in size. Differential expression of the antigen was detected in regenerating head and tail tissues. Taken together these data demonstrate cellular and molecular events that are specific to head regeneration.
