Determining the role of Toll-7 in the embryonic development of Drosophila melanogaster through RNAi

Cassandra Kleve
California State University, Long Beach

Since the discovery of Toll there have been 8 additional Toll-related receptors found in Drosophila melanogaster??Toll-2 (18-wheeler) through Toll-9. Toll-like receptors (TLRs) have been found in mammals and are involved in innate immunity by mediating a response to distinct microbial patterns. Cell signaling is particularly important in multicellular organisms since the behaviors of each individual cell must be regulated to meet the needs of the entire organism. During embryogenesis in Drosophila, Toll-like genes are expressed in a tissue specific manner indicating they are likely to have a developmental role. We have carried out a detailed analysis of the Toll-7 expression pattern. Toll-7 is expressed dynamically beginning during germ band extension and continuing throughout embryogenesis. We have chosen to study the role of Toll-7 through RNAi and have cloned an inverted repeat of a 635 base pair fragment of Toll-7 from the extracellular region of Toll-7 into the P-element vector pWIZ (constructed by Lee and Carthew) and have generated several transformant lines each with an independent insertion of pWIZ. Transcription of the inverted repeat is activated by GAL4, which is normally absent in Drosophila. Using lines that produce GAL4 in a tissue specific way should allow us to study the effects of Toll-7 deficiencies in particular tissues.