9952
These data will help us to better detail the CXCR4 structural requirements exhibited by different HIV - 1 strains and will direct further mutagenesis efforts aimed at better defining the domains in CXCR4 involved in the HIV - 1 Env - mediated fusion process .
 CXCR4, CXCR4, Env
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: GENE 
Text: {0} 
Answer:
 CXCR4, CXCR4, Env