Transcription factor substitution during the evolution of fungal ribosome regulation.
Coordinated ribosomal protein (RP) gene expression is crucial for cellular viability, but the transcriptional network controlling this regulon has only been well characterized in the yeast Saccharomyces cerevisiae. We have used whole-genome transcriptional and location profiling to establish that, in Candida albicans, the RP regulon is controlled by the Myb domain protein Tbf1 working in conjunction with Cbf1. These two factors bind both the promoters of RP genes and the rDNA locus; Tbf1 activates transcription at these loci and is essential. Orthologs of Tbf1 bind TTAGGG telomeric repeats in most eukaryotes, and TTAGGG cis-elements are present upstream of RP genes in plants and fungi, suggesting that Tbf1 was involved in both functions in ancestral eukaryotes. In all Hemiascomycetes, Rap1 substituted Tbf1 at telomeres and, in the S. cerevisiae lineage, this substitution also occurred independently at RP genes, illustrating the extreme adaptability and flexibility of transcriptional regulatory networks.
Hogues
Hervé
H
Biotechnology Research Institute, National Research Council, Montreal, QC H4P 2R2, Canada.
Lavoie
Hugo
H
Sellam
Adnane
A
Mangos
Maria
M
Roemer
Terry
T
Purisima
Enrico
E
Nantel
André
A
Whiteway
Malcolm
M
D001483:Base Sequence; D002176:Candida albicans / Q000235:genetics / Q000378:metabolism; D019295:Computational Biology; D004275:DNA, Ribosomal / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D016681:Genome, Fungal; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D018085:Regulon; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D000089804:Shelterin Complex; D016615:Telomere / Q000378:metabolism; D034501:Telomere-Binding Proteins / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
C481542:CBF1 protein, Candida albicans; D004275:DNA, Ribosomal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C474965:RAP1 protein, Candida albicans; C440829:RAP1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D000089804:Shelterin Complex; C079376:TBF1 protein, S cerevisiae; D034501:Telomere-Binding Proteins; D014157:Transcription Factors