In this task, you are given a sentence. You are expected to recognize the name of gene or protein. Although there might be several correct answers, you need to write one of them.

Vibrio cholerae iron transport : haem transport genes are linked to one of two sets of tonB , exbB , exbD genes .
exbD genes

A regulatory element of the empty spiracles homeobox gene is composed of three distinct conserved regions that bind regulatory proteins .
empty spiracles

These studies reveal that CREM , a tissue - specific factor , is expressed and regulated by gonadotropins in the ovary , that the predominant CREM transcripts encode the repressor protein ICER , and that ICER is capable of inhibiting cAMP - induced expression of the inhibin alpha - subunit gene .
repressor protein ICER