The ABF1 factor is the transcriptional activator of the L2 ribosomal protein genes in Saccharomyces cerevisiae

1990 ◽  
Vol 10 (5) ◽  
pp. 2437-2441
Author(s):  
F Della Seta ◽  
S A Ciafré ◽  
C Marck ◽  
B Santoro ◽  
C Presutti ◽  
...  

The same factor, ABF1, binds to the promoters of the two gene copies (L2A and L2B) coding for the ribosomal protein L2 in Saccharomyces cerevisiae. In vitro binding experiments and in vivo functional analysis showed that the different affinities of the L2A and L2B promoters for the ABF1 factor are responsible for the differential transcriptional activities of the two gene copies. The presence of ABF1-binding sites in front of many housekeeping genes suggests a general role for ABF1 in the regulation of gene activity.


1990 ◽  
Vol 10 (5) ◽  
pp. 2437-2441 ◽  
Author(s):  
F Della Seta ◽  
S A Ciafré ◽  
C Marck ◽  
B Santoro ◽  
C Presutti ◽  
...  

The same factor, ABF1, binds to the promoters of the two gene copies (L2A and L2B) coding for the ribosomal protein L2 in Saccharomyces cerevisiae. In vitro binding experiments and in vivo functional analysis showed that the different affinities of the L2A and L2B promoters for the ABF1 factor are responsible for the differential transcriptional activities of the two gene copies. The presence of ABF1-binding sites in front of many housekeeping genes suggests a general role for ABF1 in the regulation of gene activity.



1993 ◽  
Vol 13 (4) ◽  
pp. 2091-2103
Author(s):  
S Türkel ◽  
P J Farabaugh

Transcription of the Ty2-917 retrotransposon of Saccharomyces cerevisiae is modulated by a complex set of positive and negative elements, including a negative region located within the first open reading frame, TYA2. The negative region includes three downstream repression sites (DRSI, DRSII, and DRSIII). In addition, the negative region includes at least two downstream activation sites (DASs). This paper concerns the characterization of DASI. A 36-bp DASI oligonucleotide acts as an autonomous transcriptional activation site and includes two sequence elements which are both required for activation. We show that these sites bind in vitro the transcriptional activation protein GCN4 and that their activity in vivo responds to the level of GCN4 in the cell. We have termed the two sites GCN4 binding sites (GBS1 and GBS2). GBS1 is a high-affinity GCN4 binding site (dissociation constant, approximately 25 nM at 30 degrees C), binding GCN4 with about the affinity of a consensus UASGCN4, this though GBS1 includes two differences from the right half of the palindromic consensus site. GBS2 is more diverged from the consensus and binds GCN4 with about 20-fold-lower affinity. Nucleotides 13 to 36 of DASI overlap DRSII. Since DRSII is a transcriptional repression site, we tested whether DASI includes repression elements. We identify two sites flanking GBS2, both of which repress transcription activated by the consensus GCN4-specific upstream activation site (UASGCN4). One of these is repeated in the 12 bp immediately adjacent to DASI. Thus, in a 48-bp region of Ty2-917 are interspersed two positive and three negative transcriptional regulators. The net effect of the region must depend on the interaction of the proteins bound at these sites, which may include their competing for binding sites, and on the physiological control of the activity of these proteins.



1991 ◽  
Vol 11 (5) ◽  
pp. 2723-2735 ◽  
Author(s):  
C M Moehle ◽  
A G Hinnebusch

An amino acid limitation in bacteria elicits a global response, called stringent control, that leads to reduced synthesis of rRNA and ribosomal proteins and increased expression of amino acid biosynthetic operons. We have used the antimetabolite 3-amino-1,2,4-triazole to cause histidine limitation as a means to elicit the stringent response in the yeast Saccharomyces cerevisiae. Fusions of the yeast ribosomal protein genes RPL16A, CRY1, RPS16A, and RPL25 with the Escherichia coli lacZ gene were used to show that the expression of these genes is reduced by a factor of 2 to 5 during histidine-limited exponential growth and that this regulation occurs at the level of transcription. Stringent regulation of the four yeast ribosomal protein genes was shown to be associated with a nucleotide sequence, known as the UASrpg (upstream activating sequence for ribosomal protein genes), that binds the transcriptional regulatory protein RAP1. The RAP1 binding sites also appeared to mediate the greater ribosomal protein gene expression observed in cells growing exponentially than in cells in stationary phase. Although expression of the ribosomal protein genes was reduced in response to histidine limitation, the level of RAP1 DNA-binding activity in cell extracts was unaffected. Yeast strains bearing a mutation in any one of the genes GCN1 to GCN4 are defective in derepression of amino acid biosynthetic genes in 10 different pathways under conditions of histidine limitation. These Gcn- mutants showed wild-type regulation of ribosomal protein gene expression, which suggests that separate regulatory pathways exist in S. cerevisiae for the derepression of amino acid biosynthetic genes and the repression of ribosomal protein genes in response to amino acid starvation.



1966 ◽  
Vol 12 (6) ◽  
pp. 1157-1165 ◽  
Author(s):  
A. von Seefried ◽  
D. C. Jordan

Paromomycin (Humatin, Parke Davis & Co.), a broad-spectrum aminoglycosidic antibiotic, inhibits the incorporation of amino acids into the trypsinsoluble protein fraction of Staphylococcus aureus 257. Protein synthesis is inhibited immediately, but the synthesis of cell-wall mucopeptide and alcohol-soluble proteins and lipids is not affected for approximately 35 min after antibiotic addition to actively growing cells. Paromomycin, at the ribosomal level, prevents the attachment of amino acyl-s-RNA and causes accumulation of m-RNA.Divalent cations (Ca++ and Mg++) antagonize the bactericidal action of paromomycin and interfere with the in vivo binding of the antibiotic on both the cell surface and the intracellular binding sites. In vitro binding to free ribosomes can be prevented and reversed by both monovalent and divalent cations.Using a "cylinder-plate" method, involving the displacement of antibiotic from cellular fractions by 0.2 M MgCl2, the antibiotic can be recovered from the ribosomes, cytoplasm, and the cell wall of paromomycin-sensitive S. aureus cells, but is not found in any of these fractions isolated from paromomycin-resistant cells developed from the sensitive parent strain. The resistant mutants apparently have lost the ability to adsorb and transport the antibiotic into the cell.



1988 ◽  
Vol 8 (11) ◽  
pp. 4792-4798 ◽  
Author(s):  
A Lucioli ◽  
C Presutti ◽  
S Ciafrè ◽  
E Caffarelli ◽  
P Fragapane ◽  
...  

In Saccharomyces cerevisiae, the genes coding for the ribosomal protein L2 are present in two copies per haploid genome. The two copies, which encode proteins differing in only a few amino acids, contribute unequally to the L2 mRNA pool: the L2A copy makes 72% of the mRNA, while the L2B copy makes only 28%. Disruption of the L2B gene (delta B strain) did not lead to any phenotypic alteration, whereas the inactivation of the L2A copy (delta A strain) produced a slow-growth phenotype associated with decreased accumulation of 60S subunits and ribosomes. No intergenic compensation occurred at the transcriptional level in the disrupted strains; in fact, delta A strains contained reduced levels of L2 mRNA, whereas delta B strains had almost normal levels. The wild-type phenotype was restored in the delta A strains by transformation with extra copies of the intact L2A or L2B gene. As already shown for other duplicated genes (Kim and Warner, J. Mol. Biol. 165:79-89, 1983; Leeret al., Curr. Genet. 9:273-277, 1985), the difference in expression of the two gene copies could be accounted for via differential transcription activity. Sequence comparison of the rpL2 promoter regions has shown the presence of canonical HOMOL1 boxes which are slightly different in the two genes.



1993 ◽  
Vol 13 (4) ◽  
pp. 2586-2592 ◽  
Author(s):  
F Messenguy ◽  
E Dubois

ARGRI, ARGRII, and ARGRIII regulatory proteins control the expression of arginine anabolic and catabolic genes in Saccharomyces cerevisiae. We have shown that MCM1 is part of the ARGR regulatory complex, by in vitro binding experiments, at the ARGR5,6 promoter. The participation of MCM1 in the regulation of arginine metabolism is confirmed by the behavior of an mcm1-gcn4 mutant, which is affected in the repression of arginine anabolic genes. In this mcm1 mutant, synthesis of the catabolic enzymes is rather constitutive, but this derepression requires the integrity of the ARGR system and of the target sequences of these proteins in the CAR1 promoter. Our in vitro binding experiments confirm the presence of MCM1 in the protein complex interacting with the promoters of the catabolic CAR1 and CAR2 genes. This is the first in vivo transcription role ascribed to MCM1 other than its role in the transcription of cell-type-specific genes.



1988 ◽  
Vol 8 (11) ◽  
pp. 4792-4798
Author(s):  
A Lucioli ◽  
C Presutti ◽  
S Ciafrè ◽  
E Caffarelli ◽  
P Fragapane ◽  
...  

In Saccharomyces cerevisiae, the genes coding for the ribosomal protein L2 are present in two copies per haploid genome. The two copies, which encode proteins differing in only a few amino acids, contribute unequally to the L2 mRNA pool: the L2A copy makes 72% of the mRNA, while the L2B copy makes only 28%. Disruption of the L2B gene (delta B strain) did not lead to any phenotypic alteration, whereas the inactivation of the L2A copy (delta A strain) produced a slow-growth phenotype associated with decreased accumulation of 60S subunits and ribosomes. No intergenic compensation occurred at the transcriptional level in the disrupted strains; in fact, delta A strains contained reduced levels of L2 mRNA, whereas delta B strains had almost normal levels. The wild-type phenotype was restored in the delta A strains by transformation with extra copies of the intact L2A or L2B gene. As already shown for other duplicated genes (Kim and Warner, J. Mol. Biol. 165:79-89, 1983; Leeret al., Curr. Genet. 9:273-277, 1985), the difference in expression of the two gene copies could be accounted for via differential transcription activity. Sequence comparison of the rpL2 promoter regions has shown the presence of canonical HOMOL1 boxes which are slightly different in the two genes.



1990 ◽  
Vol 10 (4) ◽  
pp. 1432-1438
Author(s):  
D M Ruden

When the DNA-binding site for the Saccharomyces cerevisiae transcription activator GAL4 is placed upstream of the Schizosaccharomyces pombe ADH1 TATA box, transcription of the ADH1 gene is activated in S. pombe in vivo by an endogenous transcription factor. In vitro studies show that this S. pombe protein, PGA4, binds specifically to DNA containing a GAL4 site and that when two GAL4 sites are present, this protein binds cooperatively. Cooperating binding of PGA4 to DNA is favored if the GAL4 sites are separated by an integral number of turns of the DNA helix.



1994 ◽  
Vol 240 (3) ◽  
pp. 243-255 ◽  
Author(s):  
Engbert A. Kooi ◽  
Carla A. Rutgers ◽  
Monique J. Kleijmeer ◽  
Jan van 't Riet ◽  
Jaap Venema ◽  
...  


Genetics ◽  
1998 ◽  
Vol 150 (4) ◽  
pp. 1429-1441 ◽  
Author(s):  
Jutta Deckert ◽  
Ana Maria Rodriguez Torres ◽  
Soo Myung Hwang ◽  
Alexander J Kastaniotis ◽  
Richard S Zitomer

Abstract Aerobic repression of the hypoxic genes of Saccharomyces cerevisiae is mediated by the DNA-binding protein Rox1 and the Tup1/Ssn6 general repression complex. To determine the DNA sequence requirements for repression, we carried out a mutational analysis of the consensus Rox1-binding site and an analysis of the arrangement of the Rox1 sites into operators in the hypoxic ANB1 gene. We found that single base pair substitutions in the consensus sequence resulted in lower affinities for Rox1, and the decreased affinity of Rox1 for mutant sites correlated with the ability of these sites to repress expression of the hypoxic ANB1 gene. In addition, there was a general but not complete correlation between the strength of repression of a given hypoxic gene and the compliance of the Rox1 sites in that gene to the consensus sequence. An analysis of the ANB1 operators revealed that the two Rox1 sites within an operator acted synergistically in vivo, but that Rox1 did not bind cooperatively in vitro, suggesting the presence of a higher order repression complex in the cell. In addition, the spacing or helical phasing of the Rox1 sites was not important in repression. The differential repression by the two operators of the ANB1 gene was found to be due partly to the location of the operators and partly to the sequences between the two Rox1-binding sites in each. Finally, while Rox1 repression requires the Tup1/Ssn6 general repression complex and this complex has been proposed to require the aminoterminal regions of histones H3 and H4 for full repression of a number of genes, we found that these regions were dispensable for ANB1 repression and the repression of two other hypoxic genes.



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