+------------SUBJ:V-N------------+                                    
      +-------COMP:N-N(of)-------+     +----------COMP:V-N(in)---------+    
      |           +-MOD_ATT:N-ADJ+     |              +--MOD_ATT:N-ADJ-+    
      |           |       +MOD_AT+     |              |         +MOD_AT+    
      |           |       |      |     |              |         |      |    
 Expression of __SP__ __NODE__ mRNA occurs in undifferentiated thp 1 cells .
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,cell)
MOD_ATT:N-ADJ (cell,undifferentiated)
MOD_ATT:N-N (cell,thp)