LOVETT, D.L.*; TANNER, C.A.; GLOMSKI, K.; TOWLE, D.W.; The College of New Jersey, Ewing; Mount Desert Island Biological Laboratory, Salsbury Cove, ME; The College of New Jersey, Ewing; Mount Desert Island Biological Laboratory, Salsbury Cove, ME; The College of New Jersey, Ewing; Mount Desert Island Biological Laboratory, Salsbury Cove, ME: Induction of gene expression for Na⁺,K⁺-ATPase and actin during acclimation of the blue crab Callinectes sapidus to dilute seawater

The data presented here confirms and extends the results of previous work on the time-course changes in Na⁺,K⁺-ATPase mRNA in gill epithelium during the acclimation of the blue crab Callinectes sapidus to dilute seawater. The amount of α-subunit of Na⁺,K⁺-ATPase in gill tissue measured in Western blots increased by 5-fold when normalized to the amount of actin in the tissue. The amount of actin per mg protein actually decreased during acclimation. Using quantitative real time PCR; we found a 2.5-fold increase in the relative amount of Na⁺,K⁺-ATPase &alpha:-subunit mRNA, an almost 4-fold increase in actin mRNA, but only a slight increase in the relative amount of arginine kinase mRNA in samples normalized to total RNA content. Arginine kinase mRNA also was selected to normalize the concentrations of mRNA for the other two proteins. When values were normalized to arginine kinase mRNA content, the amount of Na⁺,K⁺-ATPase mRNA increased by 1.5-fold, while the amount of actin increased over 2-fold. The increase in mRNA levels was gradual, and reached a peak between 4 and 8 days after crabs were transferred to dilute seawater. Although the amount of Na⁺,K⁺-ATPase enzyme remained elevated after acclimation to dilute seawater, the increase in mRNA levels was relatively short-termed; by the time the crabs had acclimated to dilute seawater, the Na⁺,K⁺-ATPase mRNA levels had returned to the initial levels measured in crabs acclimated to full-strength seawater. The relative amount of actin mRNA also returned to initial levels by the end of acclimation.