Induction synchrony in the fission yeast Schizosaccharomyces pombe

Abstract

Asynchronous growing cultures of the fission yeast Schizosaccharomyces pombe can be induced to divide synchronously by adding deoxyadenosine (2 mM) and then removing it at the end of 3 h. DNA synthesis is inhibited by this treatment and after the end of it there is a burst of synchronous DNA synthesis followed by a synchronous division. This synchronous division is followed by a second less synchronous division and the time between them is about 60% of the normal cycle time. Although DNA synthesis is inhibited, there is little or no inhibition of RNA synthesis and dry mass increase which continue unaffected through the treatment. As a result, both the mean size of dividing cells and their variation in size are much greater at the first synchronous division than they are in normal asynchronous cultures or after selection synchrony. This method of induction synchrony, when compared with selection synchrony, may provide a useful way of identifying which events in the cycle are closely associated with DNA synthesis and division. A second method of inducing synchrony is to suspend cells from the declining growth phase of a batch culture in fresh medium. It is difficult, however, to repeat and has not been followed up in any detail.