Regulation of gene transcription
- cell growth and differentiation
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- All cells in the body contain the same DNA and genes.
- Just a small fraction of the genes are transcribed in each cell type.
- Different cell types express different genes.
- The human genome: approximately 30,000 genes.
Several signal molecules including hormones, cytokines and growth factors bind receptors on the plasma membrane thereby activating them and regulating gene expression via intracellular signal pathways (second messengers), while the fat soluble growth factors (sterols, fatty acids, vitamin A, D and eicosanoids) regulate gene expression directly, with no second messengers.
Vitamin A-driven transcription regulation is important for:
- Embryonal development
- Growth
- Reproduction
- Differentiation of epithelial tissues
- Immune response