Answer:
Negative control
Explanation:
When a protein binds to specific sites at DNA and serves to reduce the rate of gene expression, the protein is said to exert negative control. These proteins may be transcription factors that down-regulate the gene expression. One of the examples is the lac repressor encoded by the lac I gene of the lac operon. Binding of repressor protein to the operator sequence prevents RNA polymerase to transcribe the genes. This is called negative control of lac operon.
