- Transcription factors are proteins that help turn specific genes "on" or "off" by binding to nearby DNA.
- Transcription factors that are activators boost a gene's transcription. Repressors decrease transcription.
- Groups of transcription factor binding sites called enhancers and silencers can turn a gene on/off in specific parts of the body.
- Transcription factors allow cells to perform logic operations and combine different sources of information to "decide" whether to express a gene.
Transcription: The key control point
- If a gene is not transcribed in a cell, it can't be used to make a protein in that cell.
- If a gene does get transcribed, it is likely going to be used to make a protein (expressed). In general, the more a gene is transcribed, the more protein that will be made.
How do transcription factors work?
How is this different from E. coli?
Turning genes on in specific body parts
Example: Modular mouse
Evolution of development
Transcription factors and cellular "logic"
- Activator A is present only in skin cells
- Activator B is active only in cells receiving "divide now!" signals (growth factors) from neighbors
- Repressor C is produced when a cell's DNA is damaged