You are investigating the synthesis of a purple pigment by a soil bacterium you isolated. You observe that small colonies are white but as they grow they get more and more purple. After sequencing the genome, you find an operon that contains genes similar to those involved in pigment production in related bacteria. You also find genes in the pigment synthesis operon that could produce proteins highly similar to LuxR and LuxI. With this information in mind, which of the following best describes how pigment synthesis is regulated in your purple bacterium? a. The Luxl homolog binds DNA upstream of the pigment operon and enhances gene expression.
b. AHL binds a sigma factor which recruits RNA polymerase to the pigment operon.
c. Pigment production is probably regulated by quorum sensing but you don't know yet if the LuxR homolog is a repressor or activator.
d. An AHL binds the LuxR homolog which acls as an activator of the pigment operon.
e. When AHL binds a repressor protein, the LuxR homolog repressor releases the operator and the pigment operon is expressed.