The expression of proliferating cell nuclear antigen (PCNA) in leukemia cell lines HL-60 and K-562 at the light and...

PCNA antigen was localized at the light and electron microscopes level in two human leukemia cell lines HL-60 and K-562. PCNA expression was used to discriminate cycling from non-cycling cells. PCNA protein at the level of the light microscope was present in 70% of the cell in HL-60 cell line and in 65% of the cells in K-562 line. Streptavidin immunogold method was used for localization of PCNA expression at the ultrastructural level. Positive staining for this protein was seen as granular pattern in the nucleus and in the cytoplasm. In the nucleus the gold particles were seen to be associated with heterochromatin and euchromatin of the leukemia cells. In cytoplasm it was found on the endoplasmic reticulum and associated with ribosomes. Controls of the leukemia cells incubation with normal mouse serum showed no labelling at the light and electron microscope level.