  A scenario of SO(10) grand unified theory (GUT) proposed by one of the
authors is extended to E_6 unification. This gives realistic quark and lepton
mass matrices. In neutrino sector, the model reproduces large mixing angle
(LMA) MSW solution as well as large mixing angle for atmospheric neutrino
anomaly. In this model, right-handed down quark and left-handed lepton of the
first and second generation belong to a single multiplet 27. This causes
natural suppression of flavor changing neutral current(FCNC).
