+-----------------SUBJ:V-N-----------------+                   
      +-----------COMP:N-N(of)-----------+       |                   
      |           +-----MOD_ATT:N-ADJ----+       |                   
      |           |      +-MOD_ATT:N-ADJ-+       +-COMP:V-N(in)-+    
      |           |      |       +MOD_ATT+       |        +MOD_A+    
      |           |      |       |       |       |        |     |    
 Expression of mature __SP__ __NODE__ protein occurs in HepG2 cells .
COMP:N-N(of) (expression,protein)
MOD_ATT:N-ADJ (protein,mature)
MOD_ATT:N-ADJ (protein,__SP__)
MOD_ATT:N-ADJ (protein,__NODE__)
SUBJ:V-N (occur,expression)
COMP:V-N(in) (occur,cell)
MOD_ATT:N-N (cell,HepG2)