The Schizosaccharomyces pombe DNA repair gene rhp51+ encodes a RecA-like protein with the DNA-dependent ATPase activity required for homologous recombination. The level of the rhp51+ transcript is increased by a variety of DNA-damaging agents. Its promoter has two cis-acting DNA damage-responsive elements (DREs) responsible for DNA damage inducibility. Here we report identification of Rdp1, which regulates rhp51+ expression through the DRE of rhp51+. The protein contains a zinc finger and a polyalanine tract similar to ones previously implicated in DNA binding and transactivation or repression, respectively. In vitro footprinting and competitive binding assays indicate that the core consensus sequences (NGG/TTG/A) of DRE are crucial for the binding of Rdp1. Mutations of both DRE1 and DRE2 affected the damage-induced expression of rhp51+, indicating that both DREs are required for transcriptional activation. In addition, mutations in the DREs significantly reduced survival rates after exposure to DNA-damaging agents, demonstrating that the damage response of rhp51+ enhances the cellular repair capacity. Surprisingly, haploid cells containing a complete rdp1 deletion could not be recovered, indicating that rdp1+ is essential for cell viability and implying the existence of other target genes. Furthermore, the DNA damage-dependent expression of rhp51+ was significantly reduced in checkpoint mutants, raising the possibility that Rdp1 may mediate damage checkpoint-dependent transcription of rhp51+.
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Cell Biology