The N-terminal and C-terminal domains of RAP1 are dispensable for chromatin opening and GCN4-mediated HIS4 activation in budding yeast.
Repressor activator protein 1 (RAP1) assists GCN4-mediated HIS4 activation by overcoming some repressive aspect of chromatin structure to facilitate GCN4 binding. RAP1 also participates in other nuclear processes, and discrete domains of RAP1 have been shown to have specific properties including DNA binding, DNA bending, transcriptional activation, and silencing and telomere functions. To investigate whether specific domains of RAP1 are required to "open" chromatin and help GCN4 to activate the HIS4 gene, we examined the abilities of different truncated RAP1 proteins to perturb positioned nucleosomes via a nucleosomal RAP1 site in a yeast episome in vivo, and we tested HIS4 activation in yeast strains harboring truncated RAP1 mutants. We found that neither the DNA bending domain nor the putative activation domain of RAP1 is required for its ability to perturb the chromatin structure of a plasmid containing a RAP1 site. Similarly, neither the putative activation domain nor the N-terminal DNA-bending domain was required for GCN4-mediated activation of HIS4. We also used a rap1(ts) mutant to show that continuous occupancy of the HIS4 promoter by RAP1 is required for GCN4-mediated gene activation.
Yu
L
L
Department of Biomedical Sciences, State University of New York at Albany School of Public Health, Albany, New York 12201-2002, USA.
Sabet
N
N
Chambers
A
A
Morse
R H
RH
D000429:Alcohol Oxidoreductases; D000619:Aminohydrolases; D001665:Binding Sites; D002843:Chromatin / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D005838:Genotype; D007700:Kinetics; D009097:Multienzyme Complexes / Q000235:genetics; D009707:Nucleosomes / Q000235:genetics / Q000378:metabolism; D010957:Plasmids; D011494:Protein Kinases / Q000378:metabolism*; D011755:Pyrophosphatases; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D017384:Sequence Deletion; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics*; D015533:Transcriptional Activation; D020827:rap1 GTP-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*
D002843:Chromatin; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D009097:Multienzyme Complexes; D009707:Nucleosomes; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D000429:Alcohol Oxidoreductases; C092116:HIS4 protein, S cerevisiae; D011494:Protein Kinases; D000619:Aminohydrolases; D011755:Pyrophosphatases; D020827:rap1 GTP-Binding Proteins