RAT GASTRIC H,K-ATPASE BETA-SUBUNIT GENE - INTRON EXON ORGANIZATION, IDENTIFICATION OF MULTIPLE TRANSCRIPTION INITIATION SITES, AND ANALYSIS OF THE 5'-FLANKING REGION

A rat genomic library was screened using a gastric H,K-ATPase β-subunit cDNA probe, and two clones were identified. Restriction endonuclease mapping and Southern hybridization analyses indicated that each of these clones contains the entire H,K-ATPase β-subunit gene. The nucleotide sequence was determined for the 8.75-kb transcription unit and 2.2 kb of the 5′-flanking region. The gene consists of seven exons and shows a high degree of similarity to the Na,K-ATPase β1-subunit gene. Primer extension and S1 nuclease protection analyses identified a major transcription initiation site 23 bases upstream of the translation start site and several minor transcription initiation sites located further upstream. The 5′-flanking region of the gene has two potential TATA sequences, each located 25-30 bases upstream of a transcription initiation site, and a number of potential promoter and regulatory elements. In addition, the 5′-flanking region contains nucleotide sequences that may regulate transcription through the formation of unusual DNA structures. These include a sequence that may form a triple helix and an adjacent sequence with the potential to form Z-DNA. © 1991.