Meeting Abstract

P2-78   -   The role of HNF-4 in tardigrade gut development Scott, LE*; Smith, FW; Mercer University; University of North Florida Logan.Elizabeth.Scott@live.mercer.edu http://franksmith.domains.unf.edu/

In the field of evolutionary developmental biology, tardigrades are an important species to study due to their miniaturized and simplified body plan, which allows study of how body plan development evolved. We investigated the role of HNF-4 in the tardigrade species Hypsibius exemplaris. The first step of our research was to determine if HNF-4 is conserved in the tardigrade genome. To do this, we identified a candidate HNF-4 sequence by BLAST search and did phylogenetic analyses, which confirmed the identity of our candidate as HNF-4. HNF-4 is a midgut marker in many bilaterian animals. For our next step, we hypothesized that HNF-4 is expressed in the developing midgut region of tardigrade embryos. We tested this hypothesis by in situ hybridization. We found that HNF-4 is expressed in an internal anterior region of the main body axis early in gut development. HNF-4 expression was restricted to the developing midgut later in development. Our results suggest the interesting possibility that cells that give rise to the midgut originate in an anterior region of the main body axis. Our second hypothesis was that HNF-4 controls midgut development of tardigrades. We predicted that when HNF-4 is knocked down using RNA interference, the midgut would not properly develop. We are currently working towards testing this prediction, and have produced double-stranded RNA to target HNF-4 in H. exemplaris.