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