Identification of rat γ atrial natriuretic polypeptide and characterization of the cDNA encoding its precursor

Abstract

Diuretic and smooth muscle-relaxing peptides, designated atrial natriuretic peptides (ANPs), have been identified in human^1–3 and rat^4–10 atrial tissues and implicated in the control of fluid volume and vascular function^11,12. Recently, cDNAs encoding the human² and rat^13–15 ANP precursors have been sequenced. We previously isolated from human tissue a natriuretic peptide of molecular weight (MW) 13,000 (γ-hANP) comprising 126 amino acid residues, the largest natriuretic peptide so far identified, and showed that it is directly derived from the 151-residue human ANP precursor by the removal of a signal peptide^2,3. We now report the isolation and sequence analysis of a novel rat atrial natriuretic peptide (γ-rANP) of MW 13,000, which derives from the rat ANP precursor. We also report the molecular cloning and nucleotide sequence analysis of the cDNA of the 152-residue rat ANP precursor, which is remarkably similar to the human 151-residue precursor (pre-hANP) except at the C-terminus. Differences in the rat and human precursor nucleotide sequences around the termination codons lead to a difference in processing pattern.