+------------SUBJ:V-N------------+                   
      +-------COMP:N-N(of)-------+     |                   
      |           +-MOD_ATT:N-ADJ+     +-COMP:V-N(in)-+    
      |           |       +MOD_AT+     |        +MOD_A+    
      |           |       |      |     |        |     |    
 Expression of __SP__ __NODE__ mRNA occurs in Mel57 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-N (cell,Mel57)