4148
The 1 . 9 - kb C mu RNA contains the 3 ' sequence characteristic of secreted mu chain , whereas the longer species bear that of membrane - bound mu chin .
 C mu, mu chain, mu
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 C mu, mu chain, mu