title: Natriuretic peptide receptor-3 gene (NPR3): nonsynonymous polymorphism results in significant reduction in protein expression because of accelerated degradation.
abstract: BACKGROUND- The primary role of natriuretic peptide receptor-3 (NPR3) or NPR-C is in the clearance of natriuretic peptides that play an important role in modulating intravascular volume and vascular tone. Genetic variation in NPR3 has been associated with variation in blood pressure and obesity. Despite the importance of NPR3, sequence variation in the gene has not been addressed using DNA from different ethnic populations. We set out to identify and functionally characterize genetic variation in NPR3 in 3 ethnic groups. METHODS AND RESULTS- DNA samples from 96 European American, 96 African American, and 96 Han Chinese American healthy subjects were used to resequence NPR3 exons, splice junctions, and flanking regions. We identified 105 polymorphisms, 50 of which were novel, including 8 nonsynonymous single-nucleotide polymorphisms, 7 were novel. Expression constructs were created for the nonsynonymous single-nucleotide polymorphisms. HEK293 cells were transfected with constructs for wild type and variant allozymes; and recombinant proteins were measured by quantitative Western blot analysis. The most significant change in NPR3 protein was observed for the Arg146 variant allozyme, with 20% of wild-type protein, primarily because of autophagy-dependent degradation. NPR3 structural modeling confirmed that the Arg146 variant protein was not compatible with wild-type conformation and could result in protein misfolding or instability. CONCLUSIONS- Multiple novel NPR3 genetic polymorphisms were identified in 3 ethnic groups. The Arg146 allozyme displayed a significant decrease in protein quantity because of degradation mediated predominantly by autophagy. This genetic variation could have a significant effect on the metabolism of natriuretic peptides with potential clinical implications.
authors.affiliation: Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA. pereira.naveen@mayo.edu
authors.forename: Naveen L
authors.initials: NL
authors.lastname: Pereira
authors.forename: Dong
authors.initials: D
authors.lastname: Lin
authors.forename: Linda
authors.initials: L
authors.lastname: Pelleymounter
authors.forename: Irene
authors.initials: I
authors.lastname: Moon
authors.forename: Gail
authors.initials: G
authors.lastname: Stilling
authors.forename: Bruce W
authors.initials: BW
authors.lastname: Eckloff
authors.forename: Eric D
authors.initials: ED
authors.lastname: Wieben
authors.forename: Margaret M
authors.initials: MM
authors.lastname: Redfield
authors.forename: John C
authors.initials: JC
authors.lastname: Burnett
authors.forename: Vivien C
authors.initials: VC
authors.lastname: Yee
authors.forename: Richard M
authors.initials: RM
authors.lastname: Weinshilboum
mesh_terms: D005838:Genotype; D057809:HEK293 Cells; D006239:Haplotypes; D006801:Humans; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015810:Linkage Disequilibrium; D020641:Polymorphism, Single Nucleotide; D059748:Proteolysis; D017461:Receptors, Atrial Natriuretic Factor / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics
chemical_list: D007527:Isoenzymes; D011994:Recombinant Proteins; D017461:Receptors, Atrial Natriuretic Factor; C073616:atrial natriuretic factor receptor C