Submitted to: Comparative Endocrinology International Congress Abstracts
Publication Type: Proceedings
Publication Acceptance Date: 4/10/2005
Publication Date: 5/15/2005
Citation: Leder, E.H., Silverstein, J. 2005. The proopiomelanocortin genes in rainbow trout (oncorhynchus mykiss): multiple genesand differential expression. Comparative Endocrinology International Congress Abstracts. Abstract 7.3, Boston, MA 5/23 - 5/28/2005.
Technical Abstract: The pro-opiomelanocortin gene (POMC) is a precursor for several important peptide hormones involved in a variety of functions ranging from stress response to energy homeostasis. In mammals and fish, the POMC-derived peptide melanocyte stimulating hormone (MSH) is known to be involved in appetite suppression through its interaction with melanocortin-4 receptors. The details of energy homeostasis in fishes are beginning to be elucidated and many of the genes involved in mammalian neuroendocrine signaling pathways are being discovered in fish. In salmonid fishes such as the rainbow trout, genome duplication has added another degree of complexity when trying to determine gene function and homology with other vertebrates. This is true of the POMC gene. Two copies of the POMC gene have been identified, A and B, presumably resulting from the salmonid duplication. However, while investigating POMC for its role in the feeding response of rainbow trout, three distinct cDNA transcripts were identified for POMC-A. One of these transcripts is a splice-variant, but the other two appear to be separate genes. This novel POMC was more similar to POMC-A than POMC-B, but the deduced amino acid sequence of the coding sequence had 39 amino acid differences, 5 deleted amino acids, and 5 inserted amino acids. Real-time PCR assays were developed for the different POMC genes and transcripts, and relative expression was examined in a variety of tissues. Relative expression of POMC transcripts was also examined during larval development and in response to food deprivation.