Madin–Darby canine kidney (MDCK) cells, which do not normally express the proteoglycan (PG) serglycin, were stably transfected with cDNA for human serglycin fused to a polyhistidine tag (His-tag). Clones with differ-ent levels of serglycin mRNA expression were generated. One clone with lower and one with higher serglycin mRNA expression were selected for this study.