gel retardation

[WANZ at QUCDN.QueensU.CA]

Do you always expect one-band shift when you use gel retardation
to analyze drug-induced DNA-binding protein appearence (either
existing protein being modified or de novo protein being
synthesized)?
What are your comments on protein concentration caused multiple
band appearence?  When I changed total protein concentration only
2 to 3 fold, I saw multiply band appeared.  Is this caused by
protein polymerization or non-specific DNA binding by other
proteins since I didnot adjust poly(dI-dC) concentration accordingly.
Your comments to this account is greatly appreciated.  Thank you.
Zhiwei Wang