Gene expression is influenced by various factors, including:
- Chemicals in the body: This refers to hormones, nutrients, and other signaling molecules that can affect gene expression.
- Senescence: As cells age, their gene expression patterns can change, often leading to altered functionality and cellular responses.
- Protein synthesis: The products of gene expression, proteins, are synthesized based on the instructions encoded in the genes, and their levels can feedback to regulate further gene expression.
- The brain: Signals from the brain, including neurotransmitters and hormones, can influence gene expression in various tissues.
Overall, while all of the items you listed can influence gene expression, chemicals in the body and signaling interactions are typically the most direct factors.