+--------------SUBJ:V-N-------------+                 
      +--------COMP:N-N(of)-------+       +COMP:V-N(in)+    
      |           +-MOD_ATT:N-ADJ-+       |      +MOD_A+    
      |           |       +MOD_ATT+       |      | +MOD+    
      |           |       |       |       |      | |   |    
 Expression of __SP__ __NODE__ protein occurs in R + cells .
COMP:N-N(of) (expression,protein)
MOD_ATT:N-ADJ (protein,__SP__)
MOD_ATT:N-ADJ (protein,__NODE__)
SUBJ:V-N (occur,expression)
COMP:V-N(in) (occur,cell)
MOD_ATT:N-N (cell,R)
MOD_ATT:N-ADJ (cell,+)