+------SUBJ:V-N------+---COMP:V-N(in)---+       
      +COMP:N-N(of)+       |         +MOD_ATT:+       
      |            |       |         |        |       
 Expression of __NODE__ occurs in __SP__ macrophages .
COMP:N-N(of) (expression,__NODE__)
SUBJ:V-N (occur,expression)
COMP:V-N(in) (occur,macrophage)
MOD_ATT:N-ADJ (macrophage,__SP__)