Meeting Abstract

P3.170  Tuesday, Jan. 6  Evolution of the vertebrate CRF system: molecular cloning and characterization of CRF-like peptides, receptors and binding protein in the lizard, Anolis carolinensis SVANCARA, Kevin; BOORSE, Graham *; Arizona State University, West Campus; Arizona State University, West Campus graham.boorse@asu.edu

Corticotropin-releasing factor (CRF)-like peptides modulate an organism’s endocrine, autonomic, and behavioral responses to stress by binding and activating either of two G protein-coupled receptors (CRF₁ and CRF₂). At least four paralogous lineages of CRF-like peptides exist in vertebrates. Previous studies have characterized the CRF stress system across different vertebrate taxa (e.g. fish, amphibians, bird and mammals). However, no studies have characterized the CRF system of squamates (e.g. lizards and snakes). The stress system likely serves important roles in underlying common lizard behaviors such as dominance and territoriality. By analyzing the A. carolinensis genome, we have identified genes involved in the CRF system. Using molecular cloning techniques, we have successfully isolated cDNAs for lizard CRF, urocortin 3 (UCN3), CRF₁, CRF₂ and CRF-binding protein (CRFBP). The deduced amino acid sequence of each molecule shares considerable sequence similarity with its human ortholog: CRF mature peptide (100%), UCN3 mature peptide (90%), CRF₁ (75%), CRF₂ (70%), and CRFBP (77%). An additional cDNA encoding a mature peptide that shares 61% identity with human CRF and 40% with human urocortin 1 (UCN1) was also identified. Using molecular phylogenetic analyses in conjunction with synteny mapping we have tentatively identified this molecule as lizard UCN1 rather than CRF. Tissue distribution of these genes via RT-PCR and binding affinity studies are currently underway.