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