8182
The multiple biologic activities of retinoic acid ( RA ) are mediated through RAR and retinoid X receptor ( RXR ) nuclear receptors that interact with specific DNA target sequences as heterodimers ( RXR-RAR ) or homodimers ( RXR-RXR ).
 ( protein: heterodimers, None) , ( protein: homodimers, None) , ( protein: retinoid X receptor ( RXR ) nuclear receptors, None) , ( protein: RXR-RAR, None) , ( protein: RXR-RXR, None) , ( protein: RXR, None) , ( protein: RAR, None) , ( DNA: DNA target sequences, None) 
Locate the role in the text that participated in the event based on the event type and return it in the event list. 
 Option: Event type: RNA,cell type,protein,cell line,DNA, Arguments type: . 
Text: {0} 
Answer:
 ( protein: heterodimers, None) , ( protein: homodimers, None) , ( protein: retinoid X receptor ( RXR ) nuclear receptors, None) , ( protein: RXR-RAR, None) , ( protein: RXR-RXR, None) , ( protein: RXR, None) , ( protein: RAR, None) , ( DNA: DNA target sequences, None) 