Meeting Abstract
P2.156 Monday, Jan. 5 Identification of an Aquaporin and a Facilitative Urea Transporter in Rana sylvatica and Rana pipiens ROSENDALE, A.J.*; COSTANZO, J.P.; LEE JR., R.E.; Miami University; Miami University; Miami University rosendaj@muohio.edu
During periods of osmotic stress, anurans must undergo various physiological changes in order to prevent excessive dehydration. One such physiological change is the reabsorption of water and solutes, such as urea, from the urinary bladder, a process which recent evidence suggests is facilitated by membrane transport proteins. Aquaporins and facilitative urea transporters are two such transport proteins whose importance in the retention of water and urea respectively is not yet fully understood. We used the wood frog, Rana sylvatica, a terrestrial species, to investigate the expression of an aquaporin (AQP-1) and a facilitative urea transporter that were cloned from the urinary bladder. For comparative purposes, we ran parallel experiments on a less terrestrial species, R. pipiens. Both proteins showed a high degree of homology to previously reported anuran transporters, with the aquaporin being homologous to the mammalian AQP-1, and the urea transporter being homologous to the mammalian UT-A2. Quantitative real-time PCR was performed on multiple tissues with the mRNA expression of these transporters being highest in the bladder and kidney. We analyzed the expression of these transporters at the protein level with western blot techniques, using an antibody designed against a known urea transporter (fUT) from R. esculenta and a mammalian AQP-1 antibody. Consistent with our mRNA findings, expression of these transporters was highest in the bladder and kidney. Results of our study confirmed the presence of an aquaporin and facilitative urea transporter in R. sylvatica and R. pipiens and laid the foundation for future studies aimed at elucidating their role in the physiological regulation of water and solute management in amphibians. Supported by NSF grant IAB 0416750.
