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Updated: Aug 13, 2026
12:19
Analysis of Cell Cycle Position in Mammalian Cells
Published on: January 21, 2012
Cell cycle dependent growth factor regulation of gene expression
1Department of Cell Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
Journal of Cellular Physiology
|December 1, 1989
Summary
Proto-oncogene expression, including c-fos and c-myc, is crucial for fibroblast cell cycle progression. This study reveals differential regulation of c-fos and c-myc mRNA by growth factors and cell cycle phase.
Area of Science:
- Molecular Biology
- Cell Biology
- Oncogenesis
Background:
- Proto-oncogenes c-fos and c-myc are rapidly expressed in fibroblasts upon growth factor stimulation.
- The precise role of c-fos and c-myc gene products in cell cycle progression remains unclear.
- Understanding these early gene responses is key to deciphering growth factor signaling pathways.
Purpose of the Study:
- To investigate the differential regulation of c-fos and c-myc mRNA expression in fibroblasts.
- To determine the influence of platelet-derived growth factor (PDGF) and plasma on proto-oncogene expression.
- To elucidate the cell cycle-dependent and growth factor-dependent roles of c-fos and c-myc in Balb/c 3T3 murine fibroblasts.
Main Methods:
- Utilized density-dependent and metabolic inhibition to synchronize Balb/c 3T3 fibroblasts in S phase.
- Examined c-fos and c-myc mRNA expression in response to platelet-derived growth factor (PDGF) and platelet-poor plasma.
- Analyzed gene expression across different cell cycle phases (G0, G1, S, G2).
Main Results:
- c-fos mRNA induction by PDGF was cell cycle-independent, occurring in G0, S, and G2 phases.
- c-myc mRNA expression was both growth factor and cell cycle dependent.
- PDGF was essential for c-myc induction in G0 cells and for maintaining elevated levels during G1 transit.
Conclusions:
- c-fos and c-myc exhibit distinct regulatory patterns in response to growth factors and cell cycle status.
- PDGF plays a critical role in regulating c-myc expression throughout the cell cycle.
- These findings provide insights into the complex mechanisms controlling proto-oncogene expression during cell proliferation.
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