gel retardation

[WANZ at QUCDN.QueensU.CA]

Do you always expect one-band shift when analyze drug-treated cells
using the protocol of gel retardation?  How do you explain the
appearence of multiple bands when you change the total protein
concentration in the assay?  Is that a result of polymerization
of proteins or show up of low abundance DNA-binding proteins?
Direct response to this account is greatly appreciated.  Thank you.
Zhiwei