+----------SUBJ:V-N---------+    
      +----COMP:N-N(in)----+      |    
      +COMP:N-N(of)+       |      |    
      |            |       |      |    
 Expression of IGF 1 in muscle occurs .
COMP:N-N(of) (expression,1)
COMP:N-N(in) (expression,muscle)
SUBJ:V-N (occur,expression)