FIG. 2.

Growth characteristics of the rfc2 mutant at restrictive temperatures. YVN3 (RFC2) and YVN4 (rfc2-1) cells grown at 25°C were divided and incubated either at 25 or 37°C. An aliquot of cell suspension was withdrawn every hour, the number of cells was counted, and total amount of DNA, cell viability, and cell morphology were assessed. (A) Growth rate of yeast cells at 25 and 37°C was measured with an automated Coulter counter. (B) DNA synthesis in rfc2 cells at 25 and 37°C was measured as described in Materials and Methods. (C) Viability of the rfc2 mutant at 25 and 37°C was determined by plating diluted cell suspension onto YPD medium at 25°C. (D) Cell morphology (unbudded cell, small-budded cell, and large-budded [dumbbell-shaped]) was monitored with a microscope.