Expression of the Even-Skipped (Eve) Gene in Early Drosophila Embryos

Multiple Choice

Expression of the Even-skipped (Eve) gene in early Drosophila embryos is under the control of several transcription regulators. In one example, one of the Eve stripes is positioned near the anterior region of the embryo, and its regulatory module contains binding sites for Bicoid and Hunchback (activators) as well as Giant and Krüppel (inhibitors) such that the gene is expressed only in the region where concentrations of the two activators are high and the concentrations of the two inhibitors are low. A reporter gene can be placed under the control of this module, and it can be shown to form a stripe in the same place in the embryo as the corresponding stripe of Eve. Answer the following question(s) based on these findings.
-In the Eve regulatory modules, the binding sites for Giant and Krüppel are usually close to, or even overlapping with, those of Bicoid and Hunchback. This implies that Eve expression is regulated by … between the activators and regulators.

A) Feedback regulation
B) Cooperation
C) Competition
D) Feed-forward regulation