Characterization of uvi15⁺, a stress-inducible gene from Schizosaccharomyces pombe

The uvi15⁺ gene of Schizosaccharomyces pombe is a member of a group of stress-inducible genes transcription levels of which increase in response to DNA-damaging agents or heat shock. It encodes a polypeptide of calculated molecular mass 11641 Da, with no significant sequence similarity to other known heat shock proteins. The steady-state level of the uvi15⁺ gene product of about 12 kDa was increased by heat shock and canavanine, an amino acid analog. This gene also showed a transient increase in expression as cells moved into diauxic shift phase. Although deletion of the uvi15⁺ gene did not affect the mitotic growth or thermotolerance of cells, the mutant cells rapidly lost viability in stationary phase and under starvation conditions. These cells also showed a defect in sporulation ability. These results suggest that the uvi15⁺ gene encodes a stress response protein involved in the maintenance of cell viability during entry into stationary phase or under starvation conditions.