Functional Interaction of NF-Y and Sp1 Is Required for Type A Natriuretic Peptide Receptor Gene Transcription

• Published in: The Journal of biological chemistry 2001-01, Vol.276 (2), p.1516-1522
• Main Authors: Liang, Faquan, Schaufele, Fred, Gardner, David G.
• Format: Article
• Language: English
• Subjects: Animals; Aorta - metabolism; Base Sequence; beta-Galactosidase - genetics; beta-Galactosidase - metabolism; Binding Sites; CCAAT-Binding Factor - metabolism; Cell Line; Cell Nucleus - metabolism; Drosophila; Gene Expression Regulation; Genes, Reporter; Guanylate Cyclase - genetics; Muscle, Smooth, Vascular - metabolism; Mutagenesis, Site-Directed; natriuretic peptide receptor; NF-Y protein; Promoter Regions, Genetic; Protein Subunits; Rats; Receptors, Atrial Natriuretic Factor - genetics; Recombinant Fusion Proteins - metabolism; Sp1 Transcription Factor - metabolism; Transcription, Genetic; Transfection
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M006350200

The vasorelaxant and anti-mitogenic activities of the atrial and brain natriuretic peptides depend upon their binding to the type A natriuretic peptide receptor (NPR-A) expressed on the surface of vascular cells. Intervention strategies aimed at controlling NPR-A expression are limited by the paucity of studies in this area. Here we identify a sequence CCAAT between −141 and −137 of the NPR-A promoter that, when mutated, reduces promoter activity by 90% in rat aortic smooth muscle (RASM) cells. Protein/DNA cross-linking and immunoperturbation of electrophoretically shifted complexes formed between RASM nuclear extracts and an oligonucleotide surrounding the CCAAT sequence indicates that the heterotrimeric transcription factor NF-Y binds specifically to the wild-type, but not mutated, CCAAT element. Cotransfection of a dominant negative mutant of the NF-YA subunit results in a concentration-dependent decrease in the activity of the NPR-A promoter in RASM cells confirming that endogenous NF-Y is an activator of the promoter. Mutation of the CCAAT element, in conjunction with mutation of all three Sp1 sites previously shown to be involved in NPR-A promoter regulation, virtually eliminates NPR-A promoter activity in RASM cells. Coexpression of all three NF-Y subunits together with Sp1 in Drosophila cells deficient in these factors indicates that NF-Y and Sp1 act synergistically to reconstitute NPR-A promoter activity. A direct physical association between NF-Y and Sp1 can be demonstrated both in vitro by glutathione S-transferase pull-down assay and in the intact cell by coimmunoprecipitation and functional studies. Together, these studies show that NPR-A promoter activity is dominantly regulated through functional, and possibly physical, interactions of NF-Y and Sp1.