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: RXRalpha / RARalpha heterodimers and HNF - 4 homodimers bind to DR - 1 motifs on elements B and I4 , respectively .
A:
HNF - 4