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