stable cell line characterization and validation - (Feb/23/2007 )

Dear all,

After a stable cell line harboring promoter+luciferase construct was established, what are the essential steps to characterize the cell line? I have some listed below, would you please advice on which is/are required?

Western blot (looks for luciferase protein)
Real time-PCR (check the no. of integrated construct)
RT-PCR (check luciferase expression level)
luciferase assay

If the stable cell line will be used for high-throughput screening, how to validate the cell line?

Charles