title: Attribution of vascular phenotypes of the murine Egfl7 locus to the microRNA miR-126.
abstract: Intronic microRNAs have been proposed to complicate the design and interpretation of mouse knockout studies. The endothelial-expressed Egfl7/miR-126 locus contains miR-126 within Egfl7 intron 7, and angiogenesis deficits have been previously ascribed to Egfl7 gene-trap and lacZ knock-in mice. Surprisingly, selectively floxed Egfl7(Delta) and miR-126(Delta) alleles revealed that Egfl7(Delta/Delta) mice were phenotypically normal, whereas miR-126(Delta/Delta) mice bearing a 289-nt microdeletion recapitulated previously described Egfl7 embryonic and postnatal retinal vascular phenotypes. Regulation of angiogenesis by miR-126 was confirmed by endothelial-specific deletion and in the adult cornea micropocket assay. Furthermore, miR-126 deletion inhibited VEGF-dependent Akt and Erk signaling by derepression of the p85beta subunit of PI3 kinase and of Spred1, respectively. These studies demonstrate the regulation of angiogenesis by an endothelial miRNA, attribute previously described Egfl7 vascular phenotypes to miR-126, and document inadvertent miRNA dysregulation as a complication of mouse knockout strategies.
authors.affiliation: Division of Hematology, Department of Medicine, Stanford University School of Medicine, CCSR 1155, 269 Campus Drive, Stanford, CA 94305, USA.
authors.forename: Frank
authors.initials: F
authors.lastname: Kuhnert
authors.forename: Michael R
authors.initials: MR
authors.lastname: Mancuso
authors.forename: Jessica
authors.initials: J
authors.lastname: Hampton
authors.forename: Kryn
authors.initials: K
authors.lastname: Stankunas
authors.forename: Tomoichiro
authors.initials: T
authors.lastname: Asano
authors.forename: Chang-Zheng
authors.initials: CZ
authors.lastname: Chen
authors.forename: Calvin J
authors.initials: CJ
authors.lastname: Kuo
mesh_terms: D000818:Animals; D001483:Base Sequence; D002135:Calcium-Binding Proteins; D017931:DNA Primers / Q000235:genetics; D066255:EGF Family of Proteins; D018507:Gene Expression Regulation, Developmental; D007438:Introns; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008817:Mice, Mutant Strains; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000235:genetics*; D010641:Phenotype; D011506:Proteins / Q000235:genetics* / Q000378:metabolism; D012171:Retinal Vessels / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D017384:Sequence Deletion
chemical_list: D002135:Calcium-Binding Proteins; D017931:DNA Primers; D066255:EGF Family of Proteins; C479627:Egfl7 protein, mouse; D035683:MicroRNAs; D011506:Proteins