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Yeast Homologue (yeast + homologue)

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Life Sciences100%

Selected Abstracts

Ebp2p, yeast homologue of a human protein that interacts with Epstein,Barr virus Nuclear Antigen 1, is required for pre-rRNA processing and ribosomal subunit assembly

GENES TO CELLS, Issue 7 2000
Rota Tsujii
Background A defect in the secretory pathway causes the transcriptional repression of both rRNA and ribosomal protein genes in Saccharomyces cerevisiae, suggesting a coupling of ribosome synthesis and plasma membrane synthesis. Rrs1p, an essential nuclear protein, is required for the secretory response. Results EBP2, encoding the yeast homologue of a human protein that interacts with Epstein,Barr virus Nuclear Antigen 1, was cloned in a two-hybrid screen using RRS1 as a bait. The rrs1-1 mutation, which produces Rrs1p without the C-terminal half and causes a defect in the secretory response, almost abolished the interaction with Ebp2p. Ebp2p is essential for growth and is mainly localized in the nucleolus. The effects of Ebp2p depletion on ribosome biogenesis is quite similar to that of Rrs1p depletion; in the Ebp2p-depleted cells, the rate of pre-rRNA processing is slower, and significantly less mature 25S rRNA is produced compared to those in wild-type cells. The polysome pattern indicates that Ebp2p-depletion causes a decrease of 80S monosomes and polysomes, an accumulation of 40S subunits, and the appearance of half-mer polysomes. Conclusions Ebp2p is required for the maturation of 25S rRNA and 60S subunit assembly. Ebp2p may be one of the target proteins of Rrs1p for executing the signal to regulate ribosome biogenesis. [source]

Snf1-independent, glucose-resistant transcription of Adr1-dependent genes in a mediator mutant of Saccharomyces cerevisiae

MOLECULAR MICROBIOLOGY, Issue 2 2009
Elton T. Young
Summary Glucose represses transcription of a network of co-regulated genes in Saccharomyces cerevisiae, ensuring that it is utilized before poorer carbon sources are metabolized. Adr1 is a glucose-regulated transcription factor whose promoter binding and activity require Snf1, the yeast homologue of the AMP-activated protein kinase in higher eukaryotes. In this study we found that a temperature-sensitive allele of MED14, a Mediator middle subunit that tethers the tail to the body, allowed a low level of Adr1-independent ADH2 expression that can be enhanced by Adr1 in a dose-dependent manner. A low level of TATA-independent ADH2 expression was observed in the med14 -truncated strain and transcription of ADH2 and other Adr1-dependent genes occurred in the absence of Snf1 and chromatin remodeling coactivators. Loss of ADH2 promoter nucleosomes had occurred in the med14 strain in repressing conditions and did not require ADR1. A global analysis of transcription revealed that loss of Med14 function was associated with both up- and down- regulation of several groups of co-regulated genes, with ADR1 -dependent genes being the most highly represented in the upregulated class. Expression of most genes was not significantly affected by the loss of Med14 function. [source]

When machines get stuck,obstructed RNA polymerase II: displacement, degradation or suicide

BIOESSAYS, Issue 9 2002
Vincent van den Boom
The severe hereditary progeroid disorder Cockayne syndrome is a consequence of a defective transcription-coupled repair (TCR) pathway. This special mode of DNA repair aids a RNA polymerase that is stalled by a DNA lesion in the template and ensures efficient DNA repair to permit resumption of transcription and prevent cell death. Although some key players in TCR, such as the Cockayne syndrome A (CSA) and B (CSB) proteins have been identified, the exact molecular mechanism still remains illusive. A recent report provides new unexpected insights into TCR in yeast.1 The identification and characterisation of a novel protein co-purifying with the yeast homologue of CSB (Rad26) imposes reassessment of our current understanding of TCR in yeast. What about humans? BioEssays 24:780,784, 2002. © 2002 Wiley Periodicals, Inc. [source]

Parallel analysis of mutant human glucose 6-phosphate dehydrogenase in yeast using PCR colonies,

BIOTECHNOLOGY & BIOENGINEERING, Issue 5 2005
Joshua Merritt
Abstract We demonstrate a highly parallel strategy to analyze the impact of single nucleotide mutations on protein function. Using our method, it is possible to screen a population and quickly identify a subset of functionally interesting mutants. Our method utilizes a combination of yeast functional complementation, growth competition of mutant pools, and polymerase colonies. A defined mutant human glucose-6-phosphate-dehydrogenase library was constructed which contains all possible single nucleotide missense mutations in the eight-residue glucose-6-phosphate binding peptide of the enzyme. Mutant human enzymes were expressed in a zwf1 (gene encoding yeast homologue) deletion strain of Saccharomyces cerevisiae. Growth rates of the 54 mutant strains arising from this library were measured in parallel in conditions selective for active hG6PD. Several residues were identified which tolerated no mutations (Asp200, His201 and Lys205) and two (Ile199 and Leu203) tolerated several substitutions. Arg198, Tyr202, and Gly204 tolerated only 1-2 specific substitutions. Generalizing from the positions of tolerated and non-tolerated amino acid substitutions, hypotheses were generated about the functional role of specific residues, which could, potentially, be tested using higher resolution/lower throughput methods. © 2005 Wiley Periodicals, Inc. [source]