Abstract

Its is generally accepted that development and differentiation are mediated by growth factors. Imbalance in embryonic tissue growth may result in development abnormalities as manifested by malformations in organs of progeny from diabetic pregnancies in humans and in mice, which are considered to occur during organogenesis. Insulin-like growth factor I (IGF-I) and IGF-11 are polypeptide growth factors which are mitogenic and bring about differentiation in cultured cells of embryonic origin. They are considered to be important growth factors in fetal and post-natal development and are thought to act through a paracrine and/or autocrine mechanism in concert with platelet derived growth factor (PDGF). The expression of the genes for IGFs have been studied in human and rodent fetal organs after organogenesis. We propose to study by in situ hybridization the timing and pattern of the expression of the above genes during early mouse embryogenesis from day 5 to day 10 post coitum (p.c.), during organogenesis, when the genes controlling differentiation and morphogenesis of organs are gradually brought into play. The expression of the IGFs and PDGF B chain will also be followed by in situ hybridization in early mouse embryos from experimentally induced diabetic mothers. Early embryos of both human and rodent diabetic mothers are known to be growth retarded. The involvement of these genes in the development of the decidua as well as extra embryonic structures in normal and diabetic pregnancies will be analyzed. The possibility of development and tissue specific expression utilizing different processing or different promoters of IGF-II will be followed by in situ hybridization as well as RNA blot analysis using unique probes for the 5' untranslated region specific to placenta or to adult liver cDNA. We will determine the pattern and timing of production of IGFs during early development by immunocytochemistry in sections of embryos from normal pregnant mice as well as from mice rendered diabetic prior to pregnancy. The mechanism by which diabetes brings about elevated expression of IGFs in human placenta will be investigated by incubating human placental explants in different concentrations of glucose, hPL and HCG. The alteration in the rate of transcription will be followed by """"""""run-on"""""""" nuclear assays and the role of specific mRNA degradation will be followed by pulse- experiments.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
2R01HD018271-04
Application #
3315283
Study Section
Endocrinology Study Section (END)
Project Start
1985-08-01
Project End
1991-11-30
Budget Start
1988-12-01
Budget End
1989-11-30
Support Year
4
Fiscal Year
1989
Total Cost
Indirect Cost

  Institution

Name
Case Western Reserve University
Department
Type
Schools of Medicine
DUNS #
077758407
City
Cleveland
State
OH
Country
United States
Zip Code
44106

  Publications

Trojan, J; Naval, X; Johnson, T et al. (1995) Expression of serum albumin and of alphafetoprotein in murine normal and neoplastic primitive embryonic structures. Mol Reprod Dev 42:369-78
Chernicky, C L; Redline, R W; Tan, H Q et al. (1994) Expression of insulin-like growth factors I and II in conceptuses from normal and diabetic mice. Mol Reprod Dev 37:382-90
Trojan, J; Johnson, T R; Rudin, S D et al. (1994) Gene therapy of murine teratocarcinoma: separate functions for insulin-like growth factors I and II in immunogenicity and differentiation. Proc Natl Acad Sci U S A 91:6088-92
Lustig, O; Ariel, I; Ilan, J et al. (1994) Expression of the imprinted gene H19 in the human fetus. Mol Reprod Dev 38:239-46
Johnson, T R; Trojan, J; Anthony, D D et al. (1994) Gene therapy of rat brain glioblastoma by an episome-based transcriptional cassette expressing antisense IGF-I cDNA. Indian J Biochem Biophys 31:1-13
Redline, R W; Chernicky, C L; Tan, H Q et al. (1993) Differential expression of insulin-like growth factor-II in specific regions of the late (post day 9.5) murine placenta. Mol Reprod Dev 36:121-9
Trojan, J; Johnson, T R; Rudin, S D et al. (1993) Treatment and prevention of rat glioblastoma by immunogenic C6 cells expressing antisense insulin-like growth factor I RNA. Science 259:94-7
Daimon, M; Johnson, T R; Ilan, J et al. (1992) The third IGF-II promoter specifies transcription of three transcripts out of five in human placenta. Mol Reprod Dev 33:413-7
Trojan, J; Blossey, B K; Johnson, T R et al. (1992) Loss of tumorigenicity of rat glioblastoma directed by episome-based antisense cDNA transcription of insulin-like growth factor I. Proc Natl Acad Sci U S A 89:4874-8
Johnson, T R; Rudin, S D; Blossey, B K et al. (1991) Newly synthesized RNA: simultaneous measurement in intact cells of transcription rates and RNA stability of insulin-like growth factor I, actin, and albumin in growth hormone-stimulated hepatocytes. Proc Natl Acad Sci U S A 88:5287-91

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