Meeting Abstract
79.3 Tuesday, Jan. 6 Effect of season and territorial aggression on hypothalamic gene expression in song sparrows MUKAI, M.*; REPLOGLE, K.; WANG, G.; WACKER, D.; CLAYTON, D. F.; WINGFIELD, J. C.; Univ. of California, Davis; Univ. of Illinois, Urbana-Champaign; Univ. of Washington, Seattle; Univ. of Washington, Seattle; Univ. of Illinois, Urbana-Champaign; Univ. of California, Davis momukai@ucdavis.edu
Male song sparrows (Melospiza melodia morphna) are territorial year-round with two peaks of aggression in spring and fall. Neuroendocrine responses to a simulated territorial intrusion (STI) differ between breeding (spring) and non-breeding seasons (fall). In spring, STI is followed by increases in luteinizing hormone and testosterone, whereas these hormone inductions are not observed in fall. These observations suggest that there are fundamental differences in mechanisms driving neuroendrocrine responses to STI between seasons. We used spotted cDNA microarrays (SoNG 20K array) to test the hypothesis that gene expression profiles in the hypothalamus after territorial aggression would differ between the seasons. In this study, hypothalami were collected from free-ranging male song sparrows in western Washington after STI experiments, in which a sparrow was exposed to either a conspecific or a control (white-crowned sparrow) male. Our comparisons showed 152 genes that were differentially expressed between spring and fall in the control birds. There were 59 genes that were significantly different between control and STI birds in fall. However, only 14 genes were significantly different between control and STI birds in spring. These results suggest that the regulatory circuit underlying the neuroendocrine response during the breeding season requires fewer genes to be triggered by social interactions. Moreover, the genes identified in this study and their functional analyses significantly advance our basic understanding of the mechanisms that lead to differential neuroendocrine responses to aggressive interactions.
