+----------------SUBJ:V-N----------------+             
                +-------COMP:N-N(of)-------+             |             
                |           +-MOD_ATT:N-ADJ+             |             
     +MOD_ATT:N-+           |       +MOD_AT+        +-NEG+COMP:V-N+    
     |          |           |       |      |        |    |        |    
 Circadian expression of __SP__ __NODE__ mRNA does not occur in liver .
MOD_ATT:N-N (expression,circadian)
COMP:N-N(of) (expression,mRNA)
MOD_ATT:N-ADJ (mRNA,__SP__)
MOD_ATT:N-ADJ (mRNA,__NODE__)
SUBJ:V-N (occur,expression)
NEG (occur,not)
COMP:V-N(in) (occur,liver)