Global regulators of ribosome biosynthesis in yeast.
Three abundant ubiquitous DNA-binding protein factors appear to play a major role in the control of ribosome biosynthesis in yeast. Two of these factors mediate the regulation of transcription of ribosomal protein genes (rp-genes) in yeasts. Most yeast rp-genes are under transcriptional control of Rap1p (repressor-activator protein), while a small subset of rp-genes is activated through Abf1p (ARS binding factor). The third protein, designated Reb1p (rRNA enhancer binding protein), which binds strongly to two sites located upstream of the enhancer and the promoter of the rRNA operon, respectively, appears to play a crucial role in the efficient transcription of the chromosomal rDNA. All three proteins, however, have many target sites on the yeast genome, in particular, in the upstream regions of several Pol II transcribed genes, suggesting that they play a much more general role than solely in the regulation of ribosome biosynthesis. Furthermore, some evidence has been obtained suggesting that these factors influence the chromatin structure and creat a nucleosome-free region surrounding their binding sites. Recent studies indicate that the proteins can functionally replace each other in various cases and that they act synergistically with adjacent additional DNA sequences. These data suggest that Abf1p, Rap1p, and Reb1p are primary DNA-binding proteins that serve to render adjacent cis-acting elements accessible to specific trans-acting factors.
Planta
R J
RJ
Department of Biochemistry and Molecular Biology, BioCentrum Amsterdam Vrije Universiteit, The Netherlands.
Gonçalves
P M
PM
Mager
W H
WH
D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000502:physiology*; D005656:Fungal Proteins / Q000502:physiology*; D019204:GTP-Binding Proteins / Q000502:physiology; D008969:Molecular Sequence Data; D012270:Ribosomes / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000502:physiology; D020668:rap GTP-Binding Proteins
C061886:ABF1 protein, S cerevisiae; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C065681:REB1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D019204:GTP-Binding Proteins; D020668:rap GTP-Binding Proteins