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