Primary sequence, tissue specificity and expression of the Na +,K +-ATPase α 1 subunit in the European eel ( Anguilla anguilla)

Abstract

The entire cDNA nucleotide sequence of the Na +,K +-ATPase α 1 isoform was cloned from the gills of the European eel ( Anguilla anguilla) by a PCR based method. The amino acid sequence translated from the sequence shared 89.4 and 85.6% homology respectively with previously published Na +,K +-ATPase α subunit sequences from elasmobranch ( Torpedo californica) and teleost ( Catostomus commersoni) fish. The size of Na +,K +-ATPase α 1 mRNA transcripts in eel tissues was demonstrated to be 3.5 kb, except in the ovary where a 3.7 kb transcript existed. Na +,K +-ATPase α 1 mRNA was present at some level in all tissues investigated with the exception of cardiac and skeletal muscle where no Na +,K +-ATPase α l mRNA was detectable. The level of branchial Na +,K +-ATPase α 1 mRNA increased after the adaptation of freshwater eels to normal or double concentration seawater.