_____ occurs when transcription factors decrease rates of transcription.

_____ occurs when transcription factors decrease rates of transcription.

• A. Down-regulation
• B. Up-regulation
• C. Inhibition
• D. Enhancement

Answer: (A)

Down-regulation is the process where transcriptional output drops in response to regulatory cues, such as transcription factors acting to repress gene expression. When a repressor binds to DNA, or chromatin becomes less accessible, the promoter activity falls and fewer mRNA molecules are produced. This decrease in transcription rate is exactly what down-regulation describes. Up-regulation would mean an increase in transcription, which is the opposite. Enhancement implies boosting transcription, not reducing it. Inhibition is a broader term for suppression, but in the context of transcription factors specifically decreasing transcription rates, the standard term used is down-regulation.

Down-regulation is the process where transcriptional output drops in response to regulatory cues, such as transcription factors acting to repress gene expression. When a repressor binds to DNA, or chromatin becomes less accessible, the promoter activity falls and fewer mRNA molecules are produced. This decrease in transcription rate is exactly what down-regulation describes.

Up-regulation would mean an increase in transcription, which is the opposite. Enhancement implies boosting transcription, not reducing it. Inhibition is a broader term for suppression, but in the context of transcription factors specifically decreasing transcription rates, the standard term used is down-regulation.