Functional mapping of Saccharomyces cerevisiae Prp45 identifies the SNW domain as essential for viability.
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.
D000595:Amino Acid Sequence; D017124:Conserved Sequence; D015966:Gene Expression Regulation, Fungal; D017930:Genes, Reporter; D005816:Genetic Complementation Test; D006801:Humans; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D010449:Peptide Mapping; D010957:Plasmids; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D015533:Transcriptional Activation; D014162:Transfection / Q000379:methods
D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D029701:Saccharomyces cerevisiae Proteins