Cloning of a cDNA encoding an Artemia franciscana Na/K ATPase α-subunit

Abstract Clones of cDNA that code for an isoform of the Artemia franciscana Na/K ATPase α subunit (NaKAa) have been isolated. The sequence of the longest of these clones (pArATNa136) is 3595 nucleotides; it codes for a 1004-amino acid protein whose sequence is identical to that of two previously sequenced Artemia NaKAa peptides. The encoded protein is over 73 % identical to Drosophila melanogaster and vertebrate NaKAαs, and 73.8% identical to another Artemia NaKAα isoform previously described (named a2850 in this article). The two Artemia cDNA clones code for mRNAs of different size; the clone pArATNa136 codes for a 4.5-kb mRNA while the a2850 clone codes for a 3.6-kb mRNA. The degree of homology and the different size of the mRNAs encoded by both cDNAs suggest that they code for two different isoforms of the protein.