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