  Non-abelian horizontal symmetry has been considered to solve potentially SUSY
flavor problem, but simple models are suffering from various problems. In this
talk, we point out that (anomalous) U(1)_A gauge symmetry solves all the
problems in a natural way, especially, in the E_6 grand unified theories.
Combining the GUT scenario with anomalous U(1)_A gauge symmetry, in which
doublet-triplet splitting and natural gauge coupling unification are realized,
and realistic quark and lepton mass matrices are obtained including bi-large
neutrino mixings, complete E_6* SU(3)_H (or E_6*SU(2)_H) GUTs can be obtained,
in which all the three generation quarks and leptons are unified into a single
multiplet (27,3) (or two multiplets (27,2+1)). This talk is based on Ref.[1].
