+----------SUBJ:V-N----------+                    
      +----COMP:N-N(of)----+       +--COMP:V-N(in)-+    
      |            +MOD_ATT+       |         +MOD_A+    
      |            |       |       |         |     |    
 Expression of __NODE__ mRNA(s) occurs in __SP__ liver .
COMP:N-N(of) (expression,mRNA(s))
MOD_ATT:N-ADJ (mRNA(s),__NODE__)
SUBJ:V-N (occur,expression)
COMP:V-N(in) (occur,liver)
MOD_ATT:N-ADJ (liver,__SP__)