The overall objective of this proposal is to understand the relationship between the synthesis of the organic biomacromolecules and the formation of the inorganic phase of the skeletal matrix. Our hypothesis is that calcium mineral plays a dual functional role during normal embryonic skeletogenesis. We postulate that, in addition to directly forming the mineral phase of the skeletal matrix, calcium also regulates the sequential cellular differentiation and the synthesis of organic matrix components by the various cell types of the skeletal element. To test this hypothesis, we propose projects which will utilize an experimental system of calcium-deficient embryonic growth consisting of chick embryos maintained in long-term culture without the eggshell, its major calcium source. This system offers the advantage of permitting experimental modulation of calcium availability to the developing embryonic skeleton. The expression and synthesis of a differentiation-specific biomacromolecule, collagen, will be studied in the skeletal tissues of these embryos with particular attention to collagen genetic type transition which will be correlated to the status of calcium accumulation and skeletal mineralization in the developing embryo.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD017887-03
Application #
3314900
Study Section
Human Embryology and Development Subcommittee 2 (HED)
Project Start
1983-07-01
Project End
1987-04-30
Budget Start
1985-07-01
Budget End
1987-04-30
Support Year
3
Fiscal Year
1985
Total Cost
Indirect Cost
Name
University of Pennsylvania
Department
Type
Schools of Arts and Sciences
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Tuan, R S (1993) Analysis of gene expression in skeletal tissues by in situ hybridization. Bone 14:309-14
San Antonio, J D; Jacenko, O; Yagami, M et al. (1992) Polyionic regulation of cartilage development: promotion of chondrogenesis in vitro by polylysine is associated with altered glycosaminoglycan biosynthesis and distribution. Dev Biol 152:323-35
Gawande, S R; Tuan, R S (1990) Characterization of bone-derived chondrogenesis-stimulating activity on embryonic limb mesenchymal cells in vitro. Cell Tissue Kinet 23:375-90
McDonald, S A; Tuan, R S (1989) Expression of collagen type transcripts in chick embryonic bone detected by in situ cDNA-mRNA hybridization. Dev Biol 133:221-34
Tuan, R S; Lamb, B T; Jesinkey, C B (1988) Mouse placental 57-kDa calcium-binding protein: II. Localization of mRNA in mouse and human placentae by in situ cDNA hybridization. Differentiation 37:198-204
Tuan, R S; Kirwin, J J (1988) Mouse placental 57-kDa calcium-binding protein: I. Cloning of cDNA and characterization of developmental expression. Differentiation 37:98-103
San Antonio, J D; Winston, B M; Tuan, R S (1987) Regulation of chondrogenesis by heparan sulfate and structurally related glycosaminoglycans. Dev Biol 123:17-24
Tuan, R S; Kushner, T (1987) Calcium-activated ATPase of the human placenta: identification, characterization, and functional involvement in calcium transport. Placenta 8:53-64
Tuan, R S; Nguyen, H Q (1987) Cardiovascular changes in calcium-deficient chick embryos. J Exp Med 165:1418-23
Tuan, R S (1987) Mechanism and regulation of calcium transport by the chick embryonic chorioallantoic membrane. J Exp Zool Suppl 1:1-13

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