Chapter 34 - Cell Cycle Analysis by Flow and Laser-Scanning Cytometry

Abstract

The cytometric methods for cell cycle analysis can be grouped into three categories. The first comprises methods that rely on a single time point measurement of the cell population. The second category is the methods that combine time-lapse measurements of populations of cells synchronized in the cycle or whose progression through the cycle was perturbed. Methods of the third category rely on analysis of DNA replication concurrent with measurement of DNA content. The time-lapse measurements of the cohort of 5’-bromo-2’-deoxyuridine (BrdUrd)-labeled cells allows one to estimate their rate of progression through different points of the cell cycle. Apoptotic cells often have fractional DNA content due to the fact that the fragmented (low MW) DNA undergoes extraction during the staining procedure. Some cells may also lose DNA (chromatin) by shedding apoptotic bodies. Only a fraction of DNA thus remains within apoptotic cells. The expression of proliferation-associated proteins often varies during the cell cycle, as well as is different in cycling and quiescent cells.