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