title: Rejoinder: whole-culture synchronization cannot, and does not, synchronize cells.
abstract: There have been numerous proposals suggesting that whole-culture methods - in which all cells in a growing culture are treated identically - can synchronize cells. An explicit defense of these methods has been presented (Spellman and Sherlock, this issue, pp. 270-273, ). Here, this defense of whole-culture 'synchronization' is subjected to a critical evaluation leading to the conclusion that whole-culture synchronization cannot synchronize cells - at all. Whole-culture methods cannot produce a set of cells that reflects the size and genome composition of cells of any particular cell-cycle age during the normal cell cycle. Thus, in addition to the well-recognized problem of artifacts, it is proposed that experiments using whole-culture treatments (usually starvation or inhibition methods) are not suitable for cell-cycle analysis because these methods do not produce a synchronized culture.
authors.affiliation: Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor MI 48109-0620, USA. cooper@umich.edu
authors.forename: Stephen
authors.initials: S
authors.lastname: Cooper
mesh_terms: D002453:Cell Cycle / Q000235:genetics / Q000502:physiology*; D002455:Cell Division / Q000235:genetics / Q000502:physiology; D005057:Eukaryotic Cells / Q000502:physiology*; D020869:Gene Expression Profiling; D020411:Oligonucleotide Array Sequence Analysis; D013997:Time Factors