Expression of cyclin A in human leukemia cell lines HL-60 and K-562 at the level of light and electron microscope by...

In this study subcellular localization of cyclin A in the human promyelocytic leukemia cell line HL-60 and the human erythroleukemic K-562 cell line was examined by immunocytochemical methods. Studies were based on light and electron microscope evaluations. Cyclin A at the level of light microscope was present in 48% of the cells in HL-60 cell line and in 40% of the cells in K-562 line. Streptavidin-gold method was used for localization of cyclin A at the ultrastructural level. There was expression of cyclin A in the nucleus and in the cytoplasm. In the nucleus gold particles were seen to be associated with the condensed chromatin of the both leukemia cell lines. In the cytoplasm cyclin A was concentrated at a low level and was associated with ribosomes. Controls of the leukemia cells incubated with normal mouse serum showed no labeling at the light and electron microscope level.