Mammalian cells are not synchronized in G1‐phase by starvation or inhibition: considerations of the fundamental concept of G1‐phase synchronization

Abstract

Synchronization of mammalian cells by starvation‐refeeding or by inhibition‐release are among the most commonly used techniques for division cycle analysis. An alternative analysis—in the form of a Gedanken or thought experiment—is presented, casting doubt on the utility of this synchronization method. Arresting cell growth produces a culture where all cells contain a G₁ amount of DNA. However, these cells are not arrested at a particular point in the G₁‐phase. Analysis of ‘G₁ arrested cells’ suggests that, upon resumption of growth, the cells are not synchronized.