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Ontogenetic analysis of embryonic palatal type I and type II cAMP-dependent protein kinase isozymes
1Daniel Baugh Institute, Department of Anatomy, Thomas Jefferson University, Philadelphia, PA 19107.
Abstract:
The developmental processes of cell growth and differentiation are important mechanisms regulating tissue and organ formation. These processes appear to be dependent on the ligand-receptor interactions of various hormones, growth factors, and extracellular matrix molecules. In turn, ligand-receptor interactions may elevate intracellular levels of second messengers. Among the second messengers, cyclic AMP (cAMP) is known to activate cAMP-dependent protein kinases (cAMP-dPK) by binding to two major regulatory subunit isoforms, RI and RII, of this enzyme. The present study examined the occurrence of changes in the cAMP-dPK isozyme patterns during the critical period of murine palatal ontogeny between days 12 and 14 of gestation. Cyclic AMP-dPK in cytosolic preparations (27,000 x g) of murine embryonic maxillary and palatal tissue were analyzed by DEAE chromatography and photoaffinity labelling with 8-azido-[32P]cAMP followed by SDS-PAGE and autoradiography. Both techniques indicated shifting patterns of expression of RI (45,000 Mr) and RII (52,000 Mr) regulatory subunits during palatal ontogeny. Immunohistochemical localization of RI and RII revealed more intense fluorescence in the palatal epithelial layer by days 13 and 14 with an apparent greater intensity of immunostaining on the basal aspect of the epithelial layer. These results suggest an important role for cAMP-dPK in epithelial-mesenchymal cell signalling during development of the murine palate.
Insights
Changes in cyclic AMP-dependent protein kinase (cAMP-dPK) isozymes were observed during murine palate development. These shifts in RI and RII regulatory subunits suggest a role in embryonic palatal tissue signaling.
Area of Science:
- Developmental Biology
- Molecular Biology
- Cell Signaling
Background:
- Cell growth and differentiation are crucial for tissue formation, regulated by ligand-receptor interactions.
- These interactions can alter intracellular second messenger levels, such as cyclic AMP (cAMP).
- cAMP activates cAMP-dependent protein kinases (cAMP-dPK) via regulatory subunits RI and RII.
Purpose of the Study:
- To investigate changes in cAMP-dPK isozyme patterns during murine palatal development (gestation days 12-14).
- To understand the role of cAMP-dPK in embryonic palatal tissue formation and signaling.
Main Methods:
- Analysis of cytosolic cAMP-dPK from murine embryonic maxillary and palatal tissue.
- DEAE chromatography and photoaffinity labeling with 8-azido-[32P]cAMP.
- SDS-PAGE, autoradiography, and immunohistochemical localization of RI and RII subunits.
Main Results:
- Shifting expression patterns of RI (45,000 Mr) and RII (52,000 Mr) regulatory subunits were detected during palatal ontogeny.
- Immunohistochemistry showed increased RI and RII fluorescence in the palatal epithelium by days 13-14.
- Enhanced immunostaining was noted on the basal aspect of the epithelial layer.
Conclusions:
- cAMP-dependent protein kinase (cAMP-dPK) isozyme patterns change significantly during murine palatal development.
- These changes indicate a dynamic role for cAMP-dPK in regulating cellular processes during palate formation.
- Results suggest cAMP-dPK is involved in epithelial-mesenchymal signaling critical for murine palate development.