This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. A. Specific Aims Specific aims in original proposal: 1: Identify fire ant homologs of bee genes predictive of task behavior. 2: Correlate known social task-specific size changes in brain regions with differences in gene expression. 3: Silence expression of specific genes to test for loss of social behavior. Modification of specific aim 1 in response to critiques in Summary Statement of 8-10-2004: 1. Identify fire ant homologs of bee genes predictive of task behavior, and identify chemical signals used in social communication. B. Studies and Results 1. Genes involved in task behavior and social communication. We attempted to locate the brain region of protein kinase G expression by in situ hybridization, but inconsistent results were obtained. We identified 11 chemosensory protein (CSP) sequences in the Lausanne Fire Ant Library. CSP1 corresponded to a sequence which we previously found to be the major low molecular weight protein in worker antennae. We cloned and expressed recombinant CSP1 in E. coli and purified it by chromatography. The recombinant CSP1 binds to N-phenylnaphthylamine (NPN), as detected by enhancement of NPN fluorescence upon binding. We measured the affinity as about 10 ¿M, which compares with 4 ¿M for NPN binding to locust CSP-sg4. We added extracted cuticular hydrocarbons to the CSP1-NPN complex and found that one or more components of the extract displaced NPN from its binding site on CSP1. Thus, one or more signalling molecules are contained in the cuticular hydrocarbon extract. C. Significance Insect model systems are relevant to human health, and insect model systems have some advantages, including avoidance of experimentation on vertebrates and the simplicity of gene manipulations. D. Plans We will identify the region of expression of PKG in fire ant brains using immunocytochemistry. The CSP1-binding components of the cuticular hydrocarbon extract will be identified. RNAi studies of PKG will be done. E. Publications: none F. Project-generated resources: none