A novel guanylyl cyclase-A isoform: rat GC-A1 identification and mRNA localization to renal papilla and adrenal.

Natriuretic peptides modulate systemic blood pressure, diuresis and natriuresis through the stimulation of cGMP production by guanylyl cyclase-coupled natriuretic peptide receptor-A and -B (GC-A and GC-B). A novel isoform of GC-A, GC-A1, has been identified which is the result of differential splicing of a new exon, 5a. This 9 bp sequence is predicted to add proline-cysteine-glutamine to the extracellular juxtamembrane region of the receptor protein. Transcripts for GC-A1 are expressed primarily in the renal papilla and adrenal. In these tissues, its abundance relative to GC-A was 1-2.5% as assessed by quantitative PCR.