+----------SUBJ:V-N----------+                  
      +----COMP:N-N(of)----+       +-COMP:V-N(in)+    
      |            +MOD_ATT+       |        +MOD_+    
      |            |       |       |        |    |    
 Expression of __NODE__ protein occurs in Hela cells .
COMP:N-N(of) (expression,protein)
MOD_ATT:N-ADJ (protein,__NODE__)
SUBJ:V-N (occur,expression)
COMP:V-N(in) (occur,cell)
MOD_ATT:N-N (cell,Hela)