[Simultaneous measurement of kinetochore protein and DNA by flow cytometry]

We were successful in obtaining simultaneous measurements of kinetochore protein and DNA with flow cytometry using HeLa cells and KM cells; the latter originated with a squamous cell carcinoma of the oral cavity. Kinetochore protein was stained with the serum obtained from a patient with CREST syndrome and FITC-conjugated goat antihuman IgG antibody; the DNA was stained with propidium iodide. The FITC fluorescence of cells with a large DNA index was stronger than in cells with a small DNA index. The FITC intensity increased from G1 phase to G2/M phase. The rate of FITC intensity increase representing the kinetochore protein amount was greater in the early and late S phases than in the other phases. The results suggest that kinetochore protein increases in the interphase as the cell cycle unfolds.