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Expression of transforming growth factor-beta s 1-4 in chicken embryo chondrocytes and myocytes
S B Jakowlew1, P J Dillard, T S Winokur
1Laboratory of Chemoprevention, National Cancer Institute, Bethesda, Maryland 20892.
Abstract:
cDNA probes and antibodies for TGF-beta s 1, 2, 3, and 4 were used to study the expression of these different TGF-beta isoforms in cultured chicken embryo chondrocytes and cardiac myocytes, as well as in developing cartilage and heart tissues. TGF-beta s 2, 3, and 4 mRNAs, but not TGF-beta 1 mRNA, were detected in cultured chondrocytes and myocytes. Expression of TGF-beta s 2 and 4 mRNAs increased with age, while expression of TGF-beta 3 mRNA was independent of age in chondrocytes cultured from 12- to 17-day-old embryos. In contrast, expression of TGF-beta s 2, 3, and 4 mRNAs was constitutive in myocytes cultured from 7- to 9-day-old embryonic hearts; expression of TGF-beta s 3 and 4 mRNAs increased, while expression of TGF-beta 2 mRNA remained unchanged in myocytes from 10-day-old embryos. Immunoprecipitation studies demonstrated expression of TGF-beta in both the conditioned media and the cell lysates of metabolically labeled chondrocyte and myocyte cell cultures. Immunohistochemical staining of cultured chondrocytes and myocytes and of cartilage and heart tissues of developing chicken embryos with antibodies specific for each TGF-beta isoform showed immunoreactive TGF-beta s 1, 2, 3, and 4. Our results demonstrate coordinate expression of these four TGF-beta isoforms in chicken embryo chondrocytes and myocytes, both in vitro and in vivo, with expression of TGF-beta s 2, 3, and 4 mRNA and protein more prominent than that of TGF-beta 1.
Insights
This study investigated transforming growth factor-beta (TGF-beta) isoforms in chicken embryos. TGF-beta 2, 3, and 4 were more prominent than TGF-beta 1 in chondrocytes and cardiac myocytes, both in vitro and in vivo.
Area of Science:
- Developmental Biology
- Cell Biology
- Molecular Biology
Background:
- Transforming growth factor-beta (TGF-beta) signaling is crucial for embryonic development.
- Multiple TGF-beta isoforms exist, but their specific roles in early development are not fully elucidated.
- Understanding TGF-beta expression patterns in distinct cell types is key to deciphering developmental processes.
Purpose of the Study:
- To investigate the expression patterns of four TGF-beta isoforms (1, 2, 3, and 4) in chicken embryo chondrocytes and cardiac myocytes.
- To compare the expression of TGF-beta isoforms in cultured cells versus developing tissues.
- To determine age-dependent changes in TGF-beta isoform expression during embryonic development.
Main Methods:
- Utilized cDNA probes and antibodies for TGF-beta isoforms 1-4.
- Analyzed gene expression in cultured chondrocytes and myocytes from chicken embryos.
- Performed immunoprecipitation and immunohistochemical staining on cell cultures and embryonic tissues.
- Investigated age-dependent expression in cells from 7- to 17-day-old embryos.
Main Results:
- TGF-beta 2, 3, and 4 mRNAs were detected in cultured chondrocytes and myocytes, while TGF-beta 1 mRNA was not.
- Expression of TGF-beta 2 and 4 mRNAs increased with embryo age in chondrocytes; TGF-beta 3 mRNA expression was age-independent.
- In myocytes, TGF-beta 2, 3, and 4 mRNAs were constitutive, with increased expression of TGF-beta 3 and 4 and unchanged TGF-beta 2 with age.
- Immunoprecipitation confirmed TGF-beta expression in cell lysates and conditioned media.
- Immunohistochemistry revealed TGF-beta 1, 2, 3, and 4 proteins in cultured cells and embryonic tissues.
- Expression of TGF-beta 2, 3, and 4 (mRNA and protein) was more prominent than TGF-beta 1.
Conclusions:
- Demonstrated coordinate expression of all four TGF-beta isoforms in chicken embryo chondrocytes and myocytes.
- Highlighted differential expression patterns of TGF-beta isoforms in these cell types during development.
- Suggests a more significant role for TGF-beta 2, 3, and 4 compared to TGF-beta 1 in chicken embryonic cartilage and heart development.