Identification of atrial natriuretic factor gene transcripts in the central nervous system of the rat.

Abstract

Atrial natriuretic factor (ANF) gene transcripts have been identified in the hypothalamus, brainstem, and cerebral cortex of the rat. The hypothalamic transcripts are similar in overall size (.apprxeq. 1100 nucleotides), 5'' terminus, 3'' terminus, and nucleotide sequence to their counterparts synthesized in the cardiac atria. The 5'' terminus of the hypothalamic transcripts, determined by both S1 nuclease and primer-extension analysis, was located .apprxeq. 20 nucleotides downstream from the TATAAAA sequence that is thought to dictate the start of transcription. Similar 5'' tremini were identified in RNA from the brainstem and cerebral cortex. The 3'' termini of the hypothalamic transcripts mapped .apprxeq. 10 nucleotides downstream from each of two successive AATAAAA sequences that are believed to provide the cleavage signal required for subsequent polyadenylylation. The same 3'' termini were present in atrial, ventricular, lung, and pituitary RNA. To confirm the identity of the hypothalamic gene transcript, a partial-length cDNA clone encoding ANF was isolated from a hypothalamic cDNA library and sequenced. This hypothalamic clone was identical to an analogous atrial cDNA clone at each of its 612 nucleotide positions. These findings suggest that ANF peptides, previously identified in specific loci of the hypothalamus and pontine tegmentum, are synthesized locally in these tissues and support a role for this peptide in the central regulation of cardiovascular physiology.