+-------------SUBJ:V-N------------+---------COMP:V-N(in)--------+    
      +----COMP:N-N(of)---+             |            +--MOD_ATT:N-ADJ-+    
      |            +MOD_AT+        +-NEG+            |          +MOD_A+    
      |            |      |        |    |            |          |     |    
 Expression of __NODE__ mRNA does not occur in postconfluent Ob1771 cells .
COMP:N-N(of) (expression,mRNA)
MOD_ATT:N-ADJ (mRNA,__NODE__)
SUBJ:V-N (occur,expression)
NEG (occur,not)
COMP:V-N(in) (occur,cell)
MOD_ATT:N-ADJ (cell,postconfluent)
MOD_ATT:N-N (cell,Ob1771)