title: Limb reduction defects in endothelial nitric oxide synthase-deficient mice.
abstract: Nitric oxide synthases are a family of enzymes capable of converting L-arginine to L-citrulline with the subsequent release of nitric oxide (NO). NO has been shown to have multiple biologic effects depending on the isoform responsible for its production and its tissue of origin. Murine endothelial nitric oxide synthase (eNOS) is encoded by Nos3, located on mouse chromosome 5. NO produced from this isoform causes vascular smooth muscle relaxation. Other investigators have shown that the administration of nonspecific inhibitors of nitric oxide synthases to pregnant rats induces limb reduction defects. However, mice deficient in Nos3 have not previously been noted to show such abnormalities. To explore the importance of eNOS during development, we produced mice deficient in eNOS using embryonic stem cell technology. Limb reduction defects were seen in approximately 10% of the null animals. We also observed increased neonatal loss of homozygous deficient pups. One functional copy of Nos3 eliminates the risk of limb defects observed in our mouse strain. These findings have implications for understanding genetic predisposition to sporadic limb reduction defects in humans.
authors.affiliation: Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030, USA.
authors.forename: A R
authors.initials: AR
authors.lastname: Gregg
authors.forename: A
authors.initials: A
authors.lastname: Schauer
authors.forename: O
authors.initials: O
authors.lastname: Shi
authors.forename: Z
authors.initials: Z
authors.lastname: Liu
authors.forename: C G
authors.initials: CG
authors.lastname: Lee
authors.forename: W E
authors.initials: WE
authors.lastname: O'Brien
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000187:drug effects; D017880:Limb Deformities, Congenital / Q000235:genetics*; D051379:Mice; D018345:Mice, Knockout / Q000235:genetics; D019001:Nitric Oxide Synthase / Q000172:deficiency* / Q000235:genetics; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; D010641:Phenotype; D010656:Phenylephrine / Q000494:pharmacology; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D010656:Phenylephrine; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D000109:Acetylcholine