The primary goal of this research project is to delineate genetic controls of development of the embryonic axis and patterning of the neural tube in mammalian embryos. Genes postulated to play key roles in these processes, including Wnt-1 and 3a; Engrailed-1; nodal: hedgehog; and hepatic nuclear factors alpha and beta, will be disrupted in mouse whole embryo culture during gastrulation and neurulation stages of development using antisense oligonucleotides.
Specific Aims i nclude: 1. To determine the function of Wnt-1 and 3a, engrailed-1, Sonic hedgehog, nodal, and hepatic nuclear factors alpha and beta in axis formation and neural tube patterning. a. Antisense oligonucleotides targeted to each of the genes will be microinjected into the amnion of 3-5 somite stage mouse embryos undergoing the processes of neurulation and gastrulation. Embryos will be grown in whole embryo culture and the effects of the targeted gene disruptions on development will be monitored. b. Functional redundancies between genes and the interaction of genes in signalling pathways responsible for axis formation and neural tube patterning will be determined by targeting 2 or more genes simultaneously. c. Effects of targeted antisense exposures on gene expression will be monitored using quantitative PCR, quantitative in situ hybridization, and immunohistochemical procedures. 2. To determine the morphological alterations at the cell and tissue level that are altered by a targeted gene's disruption and that contribute to the abnormal phenotype. These studies will be completed using detailed histological and scanning electron microscopic techniques. 3. To determine the underlying biological effects produced by targeted gene disruption that may play a role in production of altered phenotypes. These studies will include analysis of cell death and cell proliferation patterns. Together these studies will provide information on the functional roles of these genes during embryogenesis, assist in defining genetic signals responsible for key morphogenic events, and identify cellular processes involved in development at stages when many birth defects are induced. In turn, identification of roles for these genes will provide data that will be important in defining the origins of birth defects, such as spina bifida and caudal dysgenesis.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD029495-07
Application #
2889066
Study Section
Human Embryology and Development Subcommittee 1 (HED)
Program Officer
Henken, Deborah B
Project Start
1992-08-01
Project End
2001-05-31
Budget Start
1999-06-01
Budget End
2000-05-31
Support Year
7
Fiscal Year
1999
Total Cost
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
078861598
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Sadler, T W; Merrill, Alfred H; Stevens, Victoria L et al. (2002) Prevention of fumonisin B1-induced neural tube defects by folic acid. Teratology 66:169-76
Burgoon, Jennifer M; Selhub, Jacob; Nadeau, Marie et al. (2002) Investigation of the effects of folate deficiency on embryonic development through the establishment of a folate deficient mouse model. Teratology 65:219-27
Fisher, M C; Zeisel, S H; Mar, M H et al. (2001) Inhibitors of choline uptake and metabolism cause developmental abnormalities in neurulating mouse embryos. Teratology 64:114-22
Sadler, T W (2000) Susceptible periods during embryogenesis of the heart and endocrine glands. Environ Health Perspect 108 Suppl 3:555-61
Foerst-Potts, L; Sadler, T W (1997) Disruption of Msx-1 and Msx-2 reveals roles for these genes in craniofacial, eye, and axial development. Dev Dyn 209:70-84
Sadler, T W (1997) Mouse embryos in culture: models for understanding diabetes-induced embryopathies and gene function. Int J Dev Biol 41:291-7
Augustine, K A; Liu, E T; Sadler, T W (1995) Antisense inhibition of engrailed genes in mouse embryos reveals roles for these genes in craniofacial and neural tube development. Teratology 51:300-10
Augustine, K A; Liu, E T; Sadler, T W (1995) Interactions of Wnt-1 and Wnt-3a are essential for neural tube patterning. Teratology 51:107-19
Sadler, T W; Liu, E T; Augustine, K A (1995) Antisense targeting of engrailed-1 causes abnormal axis formation in mouse embryos. Teratology 51:292-9
Augustine, K; Liu, E T; Sadler, T W (1993) Antisense attenuation of Wnt-1 and Wnt-3a expression in whole embryo culture reveals roles for these genes in craniofacial, spinal cord, and cardiac morphogenesis. Dev Genet 14:500-20