Cell cycle, DNA damage and heat shock regulate suc22+ expression in fission yeast

Harris, P., Kersey, P.J., McInerny, C.J. and Fantes, P.A. (1996) Cell cycle, DNA damage and heat shock regulate suc22+ expression in fission yeast. Molecular and General Genetics, 252(3), pp. 284-291. (doi: 10.1007/BF02173774)

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The <i>suc22</i><sup>+</sup> gene of Schizosaccharomyces pombe encodes the small subunit of ribonucleotide reductase. Two transcripts that hybridise to <i>suc22</i><sup>+</sup> have previously been described: a constitutive transcript of 1.5 kb, and a transcript of approximately 1.9 kb that is induced when DNA replication is blocked by hydroxyurea. In this paper we show that both transcripts derive from the suc22+ gene, are polyadenylated, and have transcription initiation sites separated by approximately 550 nucleotides. The absence of translation initiation codons and predicted intron splice sites within this 550 nucleotide region suggests strongly that both transcripts encode the same protein. Under normal growth conditions, the larger <i>suc22</i><sup>+</sup> transcript is present at a very low level. This low level expression is periodic during the cell cycle, showing a pattern similar to that of other genes under regulation by MCB elements with a maximum in G1/S phase. Consistent with this, there are MCB elements upstream of the initiation site of the transcript. This pattern of expression contrasts with the continuous expression, at a much higher level, of the smaller <i>suc22</i><sup>+</sup> transcript. The larger <i>suc22</i><sup>+</sup> transcript is induced by exposure of cells to 4-nitroquinoline oxide (4-NQO),a UV-mimetic agent that causes DNA damage. The transcriptional response to 4-NQO is observed in cells previously arrested in G2 by a <i>cdc2</i><sup>ts</sup> mutation, demonstrating that induction can occur outside S phase. We show that the rad1+ gene, part of the mitotic checkpoint, is required for induction of the large transcript. Exposure of cells to heat shock also induces the <i>suc22</i><sup>+</sup> large transcript: a consensus heat shock element has been identified upstream of the large transcript start site.

Item Type:Articles
Glasgow Author(s) Enlighten ID:McInerny, Dr Chris
Authors: Harris, P., Kersey, P.J., McInerny, C.J., and Fantes, P.A.
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:Molecular and General Genetics

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