TARRANT, A.M.*; CORT�S, J.; BEZY, B; JOHANNING, K.J.; CHIANG, T.C.; VARGAS, J.A.; MCLACHLAN, J.A.; Woods Hole Oceanographic Instition, Woods Hole, MA; University of Costa Rica, San Jose; University of Costa Rica, San Jose; University of New Orleans, LA; Tulane University, New Orleans, LA; University of Costa Rica, San Jose; Tulane University, New Orleans, LA: Identification and expression patterns of nuclear receptors in the coral Pocillopora damicornis

Reef-building corals and other cnidarians must regulate diverse physiological processes including intracellular symbiosis, calcification, and synchronous reproduction. These processes are poorly understood at a molecular level, and the potential for signal disruption is unknown. Nuclear receptors are transcription factors that regulate diverse aspects of animal development, differentiation and physiology. In this study, three nuclear receptor cDNAs were cloned from P. damicornis. PdNR1 and PdNR7 are putative homologs of the tailless (subfamily 2E), and COUP-TF genes (subfamily 2F), respectively. The third cDNA, PdNR6 cannot be unambiguously assigned to a known nuclear receptor subfamily. Expression of PdNR1, PdNR6 and PdNR7 transcripts was quantified by real-time qPCR in P. damicornis samples collected from Culebra Bay, Costa Rica in December 2004, June 2004 and March 2005. Expression of all three nuclear receptors and the stress-inducible heat shock protein 70 was elevated in samples collected in March relative to samples collected in December and June. Similar induction was not observed in two housekeeping genes (β-actin and 28S rRNA). Manipulative experiments are in progress to determine the effects of physical stressors on nuclear receptor expression. Future characterization of the function of these nuclear receptors will provide insight into evolution of bioregulatory pathways and a basis for investigation of signal disruption in corals. Funding provided by the Caribbean Marine Research Center CMRC-03-NRAA-01-04A (NOAA/NURP) and the Costa Rica-USA Foundation.