Mammalian Metaphase Chromosomes

This chapter describes the method for the isolation of mammalian metaphase chromosomes. This method is also used in the isolation of metaphase chromosomes from HeLa cells, L-cells, Syrian and Chinese hamster cells, mouse and human lymphoblasts, and African green monkey BSC-1 cells. All these cell lines can be grown in suspension and are heteroploid, pseudodiploid, or adapted for long-term growth in culture. As different cell lines vary in their responses to metaphase arrest agents, preliminary studies are performed to determine the concentration of colchicine or vinblastine sulfate necessary to produce maximum metaphase arrest. The purified metaphase chromosomes aggregate tenaciously in most stabilizing buffers. Such aggregates interfere with fractionation according to size classes and, with the uptake of individual chromosomes by recipient cells in gene transfer experiments.