Repression of rRNA synthesis due to a secretory defect requires the C-terminal silencing domain of Rap1p in Saccharomyces cerevisiae.
A secretory defect causes specific transcriptional repression of both ribosomal protein and ribosomal RNA genes, suggesting the coupling of plasma membrane and ribosome syntheses. We previously reported that the rap1-17 allele, which produced C-terminally truncated Rap1p, derepressed transcription of ribosomal protein genes when the secretory pathway was blocked. In this paper, we demonstrate that the rap1-17 mutation also leads to significant attenuation of transcriptional repression of rRNA genes due to a secretory defect. In contrast, the rap1-2 temperature-sensitive allele containing a unique missense mutation in the middle of the coding sequence has only a weak effect on repression. These results suggest that the C-terminal silencing domain of Rap1p is required for transcriptional repression of rDNA in response to a secretory defect. We also demonstrated that transcriptional regulation of ribosomal protein genes in response to nitrogen limitation was not affected by the rap1-17 allele, suggesting that the mechanism of nitrogen response is distinct from that of the secretory response.
Miyoshi
K
K
Graduate School of Biosphere Sciences and Graduate School of Advanced Sciences of Matter, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Japan.
Miyakawa
T
T
Mizuta
K
K
D000483:Alleles; D004275:DNA, Ribosomal / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D020868:Gene Silencing; D005800:Genes, Fungal / Q000235:genetics; D009154:Mutation / Q000235:genetics; D009584:Nitrogen / Q000378:metabolism; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D012331:RNA, Fungal / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics; D012335:RNA, Ribosomal / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D000089804:Shelterin Complex; D034501:Telomere-Binding Proteins; D013696:Temperature; D014157:Transcription Factors; D014158:Transcription, Genetic / Q000235:genetics
D004275:DNA, Ribosomal; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C440829:RAP1 protein, S cerevisiae; D012331:RNA, Fungal; D012335:RNA, Ribosomal; D029701:Saccharomyces cerevisiae Proteins; D000089804:Shelterin Complex; D034501:Telomere-Binding Proteins; D014157:Transcription Factors; D009584:Nitrogen