7018
In gel retardation assays , an RCS cell - specific protein and another closely related protein expressed only in RCS cells and primary chondrocytes bound to a 10 - bp sequence within the 18 - mer .
 None
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 None