title: Alteration of limb and brain patterning in early mouse embryos by ultrasound-guided injection of Shh-expressing cells.
abstract: A basic limitation of the study of development in the mouse is the inaccessibility of the embryos, which are encased in the maternal uterus. We demonstrate the first use of ultrasound backscatter microscopy for guiding injections of cells and other agents into early stage mouse embryos. Cells were injected into the mouse neural tube cavity as early as 9.5 days post coitus (E9.5), and into the developing limb buds as early as E10.5. Furthermore, a cell-line engineered to express the secreted factor Sonic Hedgehog (Shh) was injected into early developing mouse brains or limbs. The Shh-expressing cells were found to induce ectopic expression of the Shh target genes Patched and Hnf3beta in the dorsal brain, and to alter digit patterning in the anterior limb bud. These results show that gene misexpression studies can be performed in mouse embryos using ultrasound-guided injection of transfected cells or retroviruses. In combination with the many available mouse mutants, this method offers a new approach for analyzing genetic interactions through gain-of-function studies performed in mutant mouse backgrounds.
authors.affiliation: Skirball Institute of Biomolecular Medicine, New York University Medical Center, 540 First Avenue, New York, NY 10016, USA.
authors.forename: A
authors.initials: A
authors.lastname: Liu
authors.forename: A L
authors.initials: AL
authors.lastname: Joyner
authors.forename: D H
authors.initials: DH
authors.lastname: Turnbull
mesh_terms: D000818:Animals; D001921:Brain / Q000196:embryology*; D002461:Cell Line, Transformed; D017690:Cell Transplantation; D002531:Cerebellum / Q000166:cytology; D004268:DNA-Binding Proteins / Q000235:genetics; D004622:Embryo, Mammalian / Q000737:chemistry / Q000000981:diagnostic imaging; D005314:Embryonic and Fetal Development / Q000502:physiology; D005057:Eukaryotic Cells / Q000166:cytology / Q000378:metabolism; D005121:Extremities / Q000196:embryology*; D005260:Female; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D053823:Hedgehog Proteins; D051542:Hepatocyte Nuclear Factor 3-beta; D047908:Intracellular Signaling Peptides and Proteins; D018878:Limb Buds / Q000254:growth & development / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D009420:Nervous System / Q000196:embryology / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics; D000072079:Patched Receptors; D011247:Pregnancy; D011506:Proteins / Q000235:genetics; D011956:Receptors, Cell Surface; D015534:Trans-Activators; D014157:Transcription Factors; D014463:Ultrasonography
chemical_list: D004268:DNA-Binding Proteins; C496503:Foxa2 protein, mouse; D053823:Hedgehog Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009687:Nuclear Proteins; D000072079:Patched Receptors; D011506:Proteins; D011956:Receptors, Cell Surface; D015534:Trans-Activators; D014157:Transcription Factors; D051542:Hepatocyte Nuclear Factor 3-beta