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