Fig. 4. Release of sds22 Ts^– mutants from alpha-factor arrest. Wild-type, sds22-5 and sds22-6 cells were synchronized in G1 using alpha-factor and released at either 26°C or 37°C. Cell density and % budded cells were monitored and the DNA content measured by FACS analysis. At 37° C the mutant cells budded and replicated their DNA, but proliferation ceased after an approximately twofold increase in cell density. , wild-type (SAY306); , sds22-5 (SAY302); , sds22-6 (SAY304).