definiens: shall mean any cell line that transiently or stably expresses an arrestin protein ( including without limitation a ~-arrestin protein ) and a detectable molecule, but is not a Transfluor - Enabled Cell Line, including but not limited to U20S - rat ~-arrestin2 - RrGFP, U20S - human ~-arrestin1 - RrGFP, U20S - rat ~-arrestin EGFP, U20S - human ~-arrestin EGFP, HEK293 - rat ~-arrestin EGFP, and any other such cell line described in U.S. Patent No . 5,891,646, U.S. Patent No . 6,110,693 or International Patent Application PCTIUS03114581 . ] [ Transfluor - Starter Plasmids . shall mean any plasmid that encodes an arrestin protein ( including without limitation a ~-arrestin protein ) and a detectable molecule, including but not limited to any such plasmid described in U.S. Patent No