Functional mapping of Saccharomyces cerevisiae Prp45 identifies the SNW domain as essential for viability

J Biochem. 2002 Oct;132(4):557-63. doi: 10.1093/oxfordjournals.jbchem.a003257.

Abstract

The essential gene product Prp45 (379 aa) of Saccharomyces cerevisiae is a highly conserved, but N-terminally abridged, ortholog of the human transcriptional coactivator SKIP, which is involved in TGFbeta, Notch, and steroid hormone signaling. We used a diploid strain harboring PRP45 deletion, which is inviable in the haploid, to test for complementation with the truncated versions of Prp45. The N-terminal half of the protein (aa 1 to 190), denoted as the SNW domain, was found sufficient to support the essential function. Interestingly, substituting the SNW motif itself with AAA was compatible with viability. GFP-tagged Prp45 was localized in nuclear "speckles" over a diffuse nuclear background. We further found that Prp45 activated the transcription of a reporter gene in S. cerevisiae when targeted to DNA. The observed effect relied in part upon the presence of conserved helical repeats and upon the highly charged C-terminal domain (pI = 11.3). Prp45, which lacks most of the binding motifs of the human ortholog, and whose N-terminal half is sufficient for supporting the growth of prp45 cells, might be helpful in elucidating the essential function of SNW/SKIP proteins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Conserved Sequence
  • Gene Expression Regulation, Fungal
  • Genes, Reporter
  • Genetic Complementation Test
  • Humans
  • Microscopy, Fluorescence
  • Molecular Sequence Data
  • Nuclear Proteins / genetics*
  • Nuclear Proteins / metabolism
  • Peptide Mapping
  • Plasmids
  • Protein Structure, Tertiary
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / genetics*
  • Saccharomyces cerevisiae Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Transcriptional Activation
  • Transfection / methods

Substances

  • Nuclear Proteins
  • Proto-Oncogene Proteins
  • Saccharomyces cerevisiae Proteins