[rt-users] email address with _ in LHS flagged as invalid

[amy.rich at tufts.edu]

We have a user who's email address contains the underscore character in the
LHS.  RT is incorrectly flagging this as an invalid address when I try to
modify it via the GUI.  Could someone tell me where the regex that defines
what constitutes a valid email address is located so I can go modify it?

Thanks...