The Schizosaccharomyces pombe cdt2⁺ gene, a target of G1-S phase-specific transcription factor complex DSC1, is required for mitotic and premeiotic DNA replication

Yoshida, S.H., Al-Amodi, H., Nakamura, T., McInerny, C.J. and Shimoda, C. (2003) The Schizosaccharomyces pombe cdt2⁺ gene, a target of G1-S phase-specific transcription factor complex DSC1, is required for mitotic and premeiotic DNA replication. Genetics, 164(3), pp. 881-893.

Abstract

We have defined five sev genes by genetic analysis of Schizosaccharomyces pombe mutants, which are defective in both proliferation and sporulation. <i>sev1</i>⁺<i>/cdt2</i>⁺ was transcribed during the G1-S phase of the mitotic cell cycle, as well as during the premeiotic S phase. The mitotic expression of <i>cdt2</i>⁺ was regulated by the MCB-DSC1 system. A mutant of a component of DSC1 affected <i>cdt2</i>⁺ expression in vivo, and a <i>cdt2</i>⁺ promoter fragment containing MCB motifs bound DSC1 in vitro. <i>Cdt2</i> protein also accumulated in S phase and localized to the nucleus. <i>cdt2</i> null mutants grew slowly at 30° and were unable to grow at 19°. These <i>cdt2</i> mutants were also medially sensitive to hydroxyurea, camptothecin, and 4-nitroquinoline-1-oxide and were synthetically lethal in combination with DNA replication checkpoint mutations. Flow cytometry analysis and pulsed-field gel electrophoresis revealed that S-phase progression was severely retarded in <i>cdt2</i> mutants, especially at low temperatures. Under sporulation conditions, premeiotic DNA replication was impaired with meiosis I blocked. Furthermore, overexpression of <i>suc22</i>⁺, a ribonucleotide reductase gene, fully complemented the sporulation defect of <i>cdt2</i> mutants and alleviated their growth defect at 19°. These observations suggest that <i>cdt2</i>⁺ plays an important role in DNA replication in both the mitotic and the meiotic life cycles of fission yeast.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: McInerny, Dr Chris
• Authors: Yoshida, S.H., Al-Amodi, H., Nakamura, T., McInerny, C.J., and Shimoda, C.
• College/School: College of Medical Veterinary and Life Sciences > School of Life Sciences; College of Medical Veterinary and Life Sciences > School of Molecular Biosciences
• Journal Name: Genetics
• ISSN: 0016-6731