ISOLATION, MAPPING, AND REGULATED EXPRESSION OF THE GENE ENCODING MOUSE C-TYPE NATRIURETIC PEPTIDE

Genomic sequences encoding mouse C-type natriuretic peptide (CNP) were isolated from bacteriophage libraries and characterized by restrictio n enzyme and sequence analysis. The mouse CNP gene (Nppc) comprised at least two exons and one intron and included several cis-regulatory el ements in the 5'-flanking sequence. The deduced amino acid sequence of mouse CNP-22 was identical to other mammalian CNPs. Analysis of allel e distributions in interspecific back-cross and recombinant inbred str ains assigned Nppc to chromosome 1. CNP transcripts were detected by r ibonuclease protection analysis in brain, ovary, and uterus, with lowe r levels in testes and epididymus. Uterine CNP transcripts and protein were low in sexually immature mice and adults at estrus and increased at proestrus, but similar variations in ovarian CNP expression were n ot statistically significant. Atrial natriuretic peptide and B-type na triuretic peptide transcripts were not detected in mouse ovary or uter us. Thus CNP gene expression is regulated by tissue-specific and induc ible mechanisms in female reproductive organs. Correlations between CN P expression and uterine fluid content suggest that CNP may regulate u terine fluid balance in mice and other mammals.