+--COMP:N-N(of)--+    
      +MOD_PRED:N-AD+-COMP:ADJ-N(for)+            +MOD+    
      |             |                |            |   |    
 __NODE__(s) is necessary for differentiation of F9 cells .
MOD_PRED:N-ADJ (__NODE__(s),necessary)
COMP:ADJ-N(for) (necessary,differentiation)
COMP:N-N(of) (differentiation,cell)
MOD_ATT:N-N (cell,F9)