Regulation of Na+,K(+)-ATPase. II. Cloning and analysis of the 5'-flanking region of the rat NKAB2 gene encoding the beta 2 subunit.

We cloned a 14.5-kb fragment of genomic DNA spanning at least the first two exons of the rat Na+,K(+)-ATPase (EC 3.6.1.3) beta 2 subunit-encoding gene and 5.5 kb of the 5'-flanking region. The transcription start point (tsp) is located 595 bp upstream from the start codon. The tsp was identical for adult rat brain and spleen, both of which produce the beta 2 isoform. The TATA sequence was found 29 bp upstream from the tsp and Sp1-binding sites at nucleotides (nt) -55 and -147. In addition, multiple consensus binding sites for a wide variety of regulatory proteins were present throughout the upstream and downstream tsp-flanking regions. Conserved sequence elements which may serve for coordinated expression of the alpha and beta subunits were found in the nt sequence of the 5'-flanking region.