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