Meeting Abstract

66.3  Friday, Jan. 6  Exploring the evolutionary loss of regeneration: a comparative genomics study in planarians SIKES, JM*; NEWMARK, PA; Univ. of Illinois, Champaign-Urbana; Howard Hughes Medical Institute

Planarians possess extraordinary abilities to regenerate complete animals from small tissue fragments. However, in contrast to most flatworm species, the planarian Procotyla fluviatilis is limited in its ability to restore lost structures, failing to regenerate heads when amputated in posterior tissues. To identify the critical mechanistic failure in P. fluviatilis regeneration, we have compared the early stages of regeneration following amputation in tissues with different regeneration potentials. While the earliest regenerative phases, such as wound healing and cell proliferation, appear to occur normally in regeneration-deficient tissues, wnt/β catenin and FGF signaling as well as the reestablishment of anterior-posterior polarity fail to occur. To examine and contrast global changes in gene expression at this critical time point, we have conducted comparative transcriptomic analyses using RNAseq. Genes upregulated in regeneration-proficient tissues yet not expressed in regeneration-deficient tissues have been identified as candidates with putative functions important to the regeneration process. In an attempt to identify the permisssive and/or inhibitory factors involved in planarian regeneration, we are determining the specific roles of these genes using RNA interference in P. fluviatilis as well as in the related regeneration-competent planarian Schmidtea mediterranea.