+------------------SUBJ:V-N-----------------+                 
      +-------------COMP:N-N(of)------------+     |                 
      |           +------MOD_ATT:N-ADJ------+     |                 
      |           |       +--MOD_ATT:N-ADJ--+     +COMP:V-N(in)+    
      |           |       |         +MOD_ATT+     |       +MOD_+    
      |           |       |         |       |     |       |    |    
 Expression of __SP__ __NODE__ [__NODE__] mRNA occurs in Mef cells .
COMP:N-N(of) (expression,mRNA)
MOD_ATT:N-ADJ (mRNA,__SP__)
MOD_ATT:N-ADJ (mRNA,__NODE__)
MOD_ATT:N-N (mRNA,[__NODE__])
SUBJ:V-N (occur,expression)
COMP:V-N(in) (occur,cell)
MOD_ATT:N-N (cell,Mef)