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