13784
Full activity can be restored by the combined action of recombinant PC4 and the PC4 -depleted USA fraction , thus suggesting a joint requirement for PC4 and another, USA-derived component (s) for optimal function of Oct-1 /OCA-B in the reconstituted system .
 PC4, PC4, Oct-1, PC4, /OCA-B
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: cell line, protein, RNA, DNA, cell type 
Text: {0} 
Answer:
 PC4, PC4, Oct-1, PC4, /OCA-B