PRIMARY SEQUENCE, TISSUE-SPECIFICITY AND MESSENGER-RNA EXPRESSION OF THE NA-ATPASE BETA-1 SUBUNIT IN THE EUROPEAN EEL (ANGUILLA-ANGUILLA)(,K+)

The entire amino acid coding sequence of the Na+,K+-ATPase beta 1 isof orm was cloned from the gill of the European eel (Anguilla anguilla) b y a PCR based method. The amino acid sequence translated from the nucl eotide sequence shared 61.4 and 56.2% homology respectively with previ ously published Na+,K+ ATPase beta 1 isoform sequences from the clawed toad (Xenopus laevis) and the ray (Torpedo californica) an elasmobran ch fish. The size of the Na+,K+-ATPase beta 1 mRNA transcript in eel t issues was demonstrated to be 2.35 Kb. Detectable levels of Na+,K+-ATP ase beta 1 mRNA were found at some level in all tissues except liver a nd cardiac muscle. The level of branchial Na+,K+-ATPase beta 1 mRNA wa s observed to increase after the adaptation of fresh water eels to nor mal or double concentration sea water.