  High-energy limits of fixed-angle tree-level stringy scattering amplitudes in
the light-like linear dilaton background are calculated. Treating the time
component of the gradient of light-like dilaton field (V_0) as a moduli
parameter, we show that: (1) there exists a new fixed-point (V_0/E \to \infty)
in the moduli space of the bosonic open string theory, where a new high-energy
symmetry among scattering amplitudes can be identified, (2) this new symmetry
can be interpreted as a deformation of the flat-space high-energy symmetry, as
proposed by D. Gross. Hence, our results give a concrete illustration about the
relation between high-energy stringy symmetry and the background independent
formulation of string theory.
