+------------SUBJ:V-N------------+---------COMP:V-N(in)--------+    
      +-------COMP:N-N(of)-------+     |         +---MOD_ATT:N-ADJ---+    
      |           +-MOD_ATT:N-ADJ+     |         |      +MOD_ATT:N-AD+    
      |           |       +MOD_AT+     |         |      |     +MOD_AT+    
      |           |       |      |     |         |      |     |      |    
 Expression of __SP__ __NODE__ mRNA occurs in normal __SP__ heart tissue .
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,toilet)
MOD_ATT:N-ADJ (toilet,normal)
MOD_ATT:N-ADJ (toilet,__SP__)
MOD_ATT:N-N (toilet,heart)