  This paper is devoted to the study of the effective field theory description
of the probe D1-brane in the background of the system of two stacks of
fivebranes in type IIB theory that intersect on $R^{1,1}$. We study the
properties of the Dirac-Born-Infeld action for D1-brane moving in this
background. We will argue that this action is invariant under an additional
symmetry in the near horizon limit and that this new symmetry is closely
related to the enhanced symmetry of the I-brane background considered recently
in [hep-th/0508025]. We also solve explicitly the equation of motion of
D1-brane in the near horizon limit.
