Detailed Instructions: 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.
Q: Such tetranucleotides are common in promoter regions , particularly in activating transcription factor / cyclic AMP response element - binding protein ( ATF / CREB ) and E - box motifs , suggesting that PIF may modulate the transcription of many genes .
A:
activating transcription factor