Final answer:
Signal transduction translates extracellular signals into intracellular actions that influence gene expression via activation of transcription factors. These factors bind to DNA regulatory sequences, acting as enhancers or silencers of transcription. Chromatin changes further regulate gene expression by altering transcription factor accessibility.
Step-by-step explanation:
Signal transduction allows environmental signals to regulate genes at the DNA level by converting extracellular signals into intracellular molecular actions, influencing gene expression. When a signal molecule, such as a hormone, binds to a receptor either inside the cell or on the cell surface, it initiates a cascade of molecular events. Inside the cell, signaling pathways, like the MAPK/ERK pathway, frequently involve a chain of phosphorylation events leading to the activation of transcription factors.
These factors can then interact with the DNA in the cell's nucleus, binding to specific regulatory sequences that can either enhance or suppress transcription of target genes. Additionally, the chromatin structure may be altered, effectively changing the accessibility of transcription factors to DNA and thus contributing to the regulation of gene expression.
Chemicals in the extracellular environment, such as nutrients or toxins, can initiate transcription regulation starting with signal transduction. Transcription factors resulting from these pathways can either turn on or off gene expression. Notably, the patterns of gene expression and chromatin configurations are remembered by a cell and passed on to its descendants, allowing for appropriate cellular responses to environmental signals or programmed development cues in eukaryotic organisms.