Molecular and General Genetics MGG

, Volume 255, Issue 2, pp 166–171

The role of cysteine residues in the homeodomain protein Matα2 in mating-type control of Saccharomyces cerevisiae

  • Y. Mukai
  • Y. Ohno-Yamashita
  • Y. Oshima
  • S. Harashima
ORIGINAL PAPER

DOI: 10.1007/s004380050485

Cite this article as:
Mukai, Y., Ohno-Yamashita, Y., Oshima, Y. et al. Mol Gen Genet (1997) 255: 166. doi:10.1007/s004380050485
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Abstract

The Matα2 homeodomain protein plays a pivotal role in the control of cell type in Saccharomyces cerevisiae. The homeodomain in the C-terminal region of Matα2 functions as a DNA-binding domain and the N-terminal region, containing two cysteine residues at positions 33 and 34, is thought to be involved in formation of Matα2 homodimers via disulfide bonds. matα2 mutants, isolated in a previous study, in which haploid-specific genes cannot be repressed by the Mata1-Matα2 heterodimer but a-specific genes can be repressed by the Matα2 homodimer, were found to produce mutant Matα2 with a substitution of tyrosine or phenylalanine for Cys33. To clarify the role of Cys33 and Cys34 in the Matα2 protein, we generated several matα2 mutants by site-directed mutagenesis which had serine residues in place of these Cys residues. Transforming MATa cells with plasmids carrying these matα2 (MATα1+) mutations rendered transformants unable to mate. Northern blot analysis revealed that transcription of the a-specific gene STE2 and the haploid-specific locus RME1 in these transformants is repressed to the same level as in wild-type MATa/MATα cells. We concluded that neither Cys33 nor Cys34 is required for repression of a-specific genes by the Matα2 homodimer or of haploid-specific genes by the Mata1-Matα2 heterodimer, and therefore suggest that Matα2 homodimer formation in vivo is not mediated by disulfide linkage.

Key words Homeodomain proteinMating-type controlMatα2Disulfide bondYeast

Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Y. Mukai
    • 1
  • Y. Ohno-Yamashita
    • 1
  • Y. Oshima
    • 1
  • S. Harashima
    • 1
  1. 1.Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita-shi, Osaka 565, JapanJP