Standard and quantitative analysis of cyclin E threshold by cyclin E/DNA multiparameter flow cytometry

Abstract

The threshold of cyclin E expression at G1/S boundary is a characteristic feature of cell cycle progressing. In this study, we tried to develop a quantitative approach to analyze cyclin E threshold by multiparamter flow cytometry. The expression of cyclin E in exponentially growing MOLT-4 cells was detected under different photomultiplier tube (PMT) voltages by cyclin E/DNA multiparameter flow cytometry. Additionally, cyclin E was detected in cells which were treated with caffeine and cycloheximide (CHX) under the same PMT voltage. Moreover, the expression of cyclin E in MOLT-4 cells was compared with that in JURKAT cells. Cyclin E threshold was quantified by formula B²/A×C (A, B, C indicates the minimum, threshold, and maximum of cyclin E fluorescence intensity, respectively). Results showed that in MOLT-4 cells, cyclin E threshold calculated by formula B²/A×C was invariable under different PMT settings. It was decreased in cells treated with caffeine and remained changeless in cells treated with cycloheximide. Cyclin E threshold in JURKAT cells was much lower than that in MOLT-4 cells. It was suggested that Formula B²/A×C we firstly set up could be used to analyze cyclin E expression threshold quantitatively.

Keywords

cyclin E / threshold / quantitative analysis

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