Identification of a warm-temperature acclimation-associated 65-kDa protein encoded by a temperature- and infection-responsive gene in the Kumgang fat minnow Rhynchocypris kumgangensis

Water temperature is one of the most important factors in fish physiology; thus, it is important to identify genes that respond to changes in water temperature. In this study, we identified a warm- temperature acclimation-associated 65-kDa protein (Wap65) in the Kumgang fat minnow Rhynchocypris kumgangensis, a small, cold-freshwater fish species endemic to Korea. Kumgang fat minnow Wap65-1 (kmWap65-1) was cloned using polymerase chain reaction (PCR)-based strategies, and was found to be highly homologous with teleost Wap65-1 and mammalian hemopexin, a heme-binding protein that transfers plasma heme into hepatocytes. kmWap65-1 mRNA was expressed mainly in the liver and its expression levels were significantly increased by both short- and long-term exposure to high temperature, which was evaluated by real-time quantitative PCR. Furthermore, the expression levels of kmWap65-1 were highly elevated by exposure to bacterial lipopolysaccharide. These results indicate that kmWap65-1 expression is associated with environmental stresses such as increases in water temperature and bacterial infection. J. Exp. Zool. 325A:65-74, 2016. © 2015 Wiley Periodicals, Inc.