Answer: a regulatory protein binds to DNA and shuts down transcription
Step-by-step explanation:
Cells have the ability to control their level of gene expression, known as gene regulation. This is a process where genes can be turned on and of (like a kitchen tap) to ensure that genes are expressed at the right time and are the right genes being "created."
For example, a regulatory protein will bind to the DNA's promoter region to stop transcription. This expression prevents any further production of mRNA (messenger RNA).