+---------SUBJ:V-N--------+                       
      +----COMP:N-N(of)---+     +---COMP:V-N(in)---+    
      |            +MOD_AT+     |          +MOD_ATT+    
      |            |      |     |          |       |    
 Expression of __NODE__ mRNA occurs in M20/168C5 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,M20/168C5)