Meeting Abstract

P3.89  Friday, Jan. 6  Evolution and Function of ftz and ftz-f1 in Hemipteroid Assemblage Insects LU, Yong*; PICK, Leslie; University of Maryland; University of Maryland

fushi tarazu (ftz) arose as a duplication of a homeotic gene but functions solely in segmentation in Drosophila melanogaster as a pair-rule gene to direct the development of alternate body segments. Dm-Ftz activity is regulated by interaction with the nuclear receptor Ftz-F1. This switch in function from a homeotic gene to a segmentation gene resulted from changes in both expression pattern and protein function: Dm-Ftz is expressed in seven stripes, while the other homeotic genes are only expressed in a domain of the embryo. Dm-Ftz acquired an LXXLL motif which mediates its interaction with Ftz-F1 necessary for segmentation function, and it lost its ancestral YPWM motif necessary for homeotic function. Recent data suggest that the LXXLL motif was acquired at the stem of holometabolous insects. To understand how ftz’s role in development switched during evolution, we are studying its expression and function in the Hemipteroid assemblage, the sister group of holometabolous insects. Using RACE and modified genomic-walking, we isolated ftz and ftz-f1 from hemipteran insects, including Oncopeltus fasciatus (milkweed bugs), Acyrthosiphon pisum (Aphids), Leptoglossus occidental (Leaf-footed bug) and Halyomorpha halys (Stink bug). Combining this with genome project data reveals that Hemiptera have not acquired the LXXLL motif and many have highly degenerated YPWM motifs. To determine the roles of hemipteran ftz and ftz-f1 genes, we are examining their expression and function in Oncopeltus . Preliminary results suggest that both Of-ftz-f1 and Of-ftz are expressed in non-overlapping stripes during embryogenesis. Of-ftz-f1 parental RNAi blocked oogenesis while Of-ftz RNAi blocked embryogenesis at around one to two days after egg laying. Future studies will analyze phenotypes associated with loss of Of-ftz and Of-ftz-f1 function in embryos to determine their biological roles in this lineage.