Upstream regulatory sequences of the yeast RNR2 gene include a repression sequence and an activation site that binds the RAP1 protein

1989 ◽  
Vol 9 (12) ◽  
pp. 5359-5372
Author(s):  
H K Hurd ◽  
J W Roberts

The small subunit of ribonucleotide reductase in Saccharomyces cerevisiae (RNR2) was induced 3- to 20-fold by a variety of DNA-damaging agents. Induction of the RNR2 transcript by at least one of these agents, methyl methanesulfonate, did not require protein synthesis. To identify sequences involved in the regulation of RNR2, we introduced deletions upstream of the transcription start site. Sequences required for induction were contained within a 200-base-pair region that could confer methyl methanesulfonate inducibility on the heterologous CYC1 promoter. This region contained a repression sequence and at least two positive activation sites. One of these activation sites bound RAP1, a protein known to associate with mating-type silencers and the upstream activation sequences of a number of genes. The behavior of deletions of the repression sequence suggests that induction of RNR2 may occur, at least in part, through relief of repression.

1989 ◽  
Vol 9 (12) ◽  
pp. 5359-5372 ◽  
Author(s):  
H K Hurd ◽  
J W Roberts

The small subunit of ribonucleotide reductase in Saccharomyces cerevisiae (RNR2) was induced 3- to 20-fold by a variety of DNA-damaging agents. Induction of the RNR2 transcript by at least one of these agents, methyl methanesulfonate, did not require protein synthesis. To identify sequences involved in the regulation of RNR2, we introduced deletions upstream of the transcription start site. Sequences required for induction were contained within a 200-base-pair region that could confer methyl methanesulfonate inducibility on the heterologous CYC1 promoter. This region contained a repression sequence and at least two positive activation sites. One of these activation sites bound RAP1, a protein known to associate with mating-type silencers and the upstream activation sequences of a number of genes. The behavior of deletions of the repression sequence suggests that induction of RNR2 may occur, at least in part, through relief of repression.


1987 ◽  
Vol 7 (10) ◽  
pp. 3673-3677
Author(s):  
H K Hurd ◽  
C W Roberts ◽  
J W Roberts

We have identified, cloned, and sequenced the gene for the small subunit of ribonucleotide diphosphate reductase of Saccharomyces cerevisiae. The protein and its transcript are induced about 10-fold by the alkylating agent methyl methanesulfonate, a result which suggests that the gene is induced by DNA damage.


1987 ◽  
Vol 7 (10) ◽  
pp. 3673-3677 ◽  
Author(s):  
H K Hurd ◽  
C W Roberts ◽  
J W Roberts

We have identified, cloned, and sequenced the gene for the small subunit of ribonucleotide diphosphate reductase of Saccharomyces cerevisiae. The protein and its transcript are induced about 10-fold by the alkylating agent methyl methanesulfonate, a result which suggests that the gene is induced by DNA damage.


2013 ◽  
Vol 288 (20) ◽  
pp. 13951-13959 ◽  
Author(s):  
Yan Zhang ◽  
Xiuxiang An ◽  
JoAnne Stubbe ◽  
Mingxia Huang

The small subunit (β2) of class Ia ribonucleotide reductase (RNR) houses a diferric tyrosyl cofactor (Fe2III-Y•) that initiates nucleotide reduction in the large subunit (α2) via a long range radical transfer (RT) pathway in the holo-(α2)m(β2)n complex. The C-terminal tails of β2 are predominantly responsible for interaction with α2, with a conserved tyrosine residue in the tail (Tyr356 in Escherichia coli NrdB) proposed to participate in cofactor assembly/maintenance and in RT. In the absence of structure of any holo-RNR, the role of the β tail in cluster assembly/maintenance and its predisposition within the holo-complex have remained unknown. In this study, we have taken advantage of the unusual heterodimeric nature of the Saccharomyces cerevisiae RNR small subunit (ββ′), of which only β contains a cofactor, to address both of these issues. We demonstrate that neither β-Tyr376 nor β′-Tyr323 (Tyr356 equivalent in NrdB) is required for cofactor assembly in vivo, in contrast to the previously proposed mechanism for E. coli cofactor maintenance and assembly in vitro. Furthermore, studies with reconstituted-ββ′ and an in vivo viability assay show that β-Tyr376 is essential for RT, whereas Tyr323 in β′ is not. Although the C-terminal tail of β′ is dispensable for cofactor formation and RT, it is essential for interactions with β and α to form the active holo-RNR. Together the results provide the first evidence of a directed orientation of the β and β′ C-terminal tails relative to α within the holoenzyme consistent with a docking model of the two subunits and argue against RT across the β β′ interface.


1987 ◽  
Vol 7 (8) ◽  
pp. 2783-2793
Author(s):  
S J Elledge ◽  
R W Davis

Ribonucleotide reductase catalyzes the first step in the pathway for the production of deoxyribonucleotides needed for DNA synthesis. The gene encoding the small subunit of ribonucleotide reductase was isolated from a Saccharomyces cerevisiae genomic DNA expression library in lambda gt11 by a fortuitous cross-reaction with anti-RecA antibodies. The cross-reaction was due to an identity between the last four amino acids of each protein. The gene has been named RNR2 and is centromere linked on chromosome X. The nucleotide sequence was determined, and the deduced amino acid sequence, 399 amino acids, shows extensive homology with other eucaryotic ribonucleotide reductases. Transplason mutagenesis was used to disrupt the RNR2 gene. A novel assay using colony color sectoring was developed to demonstrate visually that RNR2 is essential for mitotic viability. RNR2 encodes a 1.5-kilobase mRNA whose levels increase 18-fold after treatment with the DNA-damaging agent 4-nitroquinoline 1-oxide. CDC8 was also found to be inducible by DNA damage, but POL1 and URA3 were not inducible by 4-nitroquinoline 1-oxide. The expression of these genes defines a new mode of regulation for enzymes involved in DNA biosynthesis and sharpens our picture of the events leading to DNA repair in eucaryotic cells.


Blood ◽  
1991 ◽  
Vol 78 (6) ◽  
pp. 1589-1595
Author(s):  
L Romao ◽  
L Osorio-Almeida ◽  
DR Higgs ◽  
J Lavinha ◽  
SA Liebhaber

We describe an alpha-thalassemia determinant in which alpha-globin expression is silenced by a deletion located 27 kb 5′ to the transcription start site of the alpha 2-globin gene. This alpha- thalassemic determinant, (alpha alpha)MM, is a member of a newly described group of thalassemic mutations resulting from deletion of locus-controlling sequences critical to globin gene expression.


2018 ◽  
Vol 19 (2) ◽  
Author(s):  
Christoph S Börlin ◽  
Nevena Cvetesic ◽  
Petter Holland ◽  
David Bergenholm ◽  
Verena Siewers ◽  
...  

1994 ◽  
Vol 14 (1) ◽  
pp. 226-237 ◽  
Author(s):  
R W Berroteran ◽  
D E Ware ◽  
M Hampsey

Mutations in the Saccharomyces cerevisiae sua8 gene were found to be suppressors of an aberrant ATG translation initiation codon in the leader region of the cyc1 gene. Analysis of cyc1 transcripts from sua8 mutants revealed that suppression is a consequence of diminished transcription initiation at the normal start sites in favor of initiation at downstream sites, including a site between the aberrant and normal ATG start codons. This effect is not cyc1 gene specific since initiation at other genes, including ADH1, CYC7, and HIS4, was similarly affected, although initiation at HIS3 and SPT15 was unaffected. The SUA8 gene was cloned and partially sequenced, revealing identity to RPB1, which encodes the largest subunit of RNA polymerase II. The sua8 suppressors are the result of single amino acid replacements of highly conserved residues. Three replacements were found either within or immediately preceding homology block D, and a fourth was found adjacent to homology block H, indicating that these regions play a role in defining start sites in vivo. Nearly identical effects on start site selection were observed for sua7 suppressors, which encode altered forms of TFIIB. Synthetic lethality was associated with double sua7 sua8 suppressor mutations, and recessive sua7 mutants failed to fully complement recessive sua8 mutants in heterozygous diploids (nonallelic noncomplementation). These data indicate that the largest subunit of RNA polymerase II and TFIIB are important determinants of transcription start site selection in S. cerevisiae and suggest that this function might be conferred by interaction between these two proteins.


Genetics ◽  
1995 ◽  
Vol 139 (2) ◽  
pp. 523-536 ◽  
Author(s):  
L J Gansheroff ◽  
C Dollard ◽  
P Tan ◽  
F Winston

Abstract Mutations in the SPT7 gene of Saccharomyces cerevisiae originally were identified as suppressors of Ty and delta insertion mutations in the 5' regions of the HIS4 and LYS2 genes. Other genes that have been identified in mutant hunts of this type have been shown to play a role in transcription. In this work we show that SPT7 is also important for proper transcription in vivo. We have cloned and sequenced the SPT7 gene and have shown that it encodes a large, acidic protein that is localized to the nucleus. The SPT7 protein contains a bromodomain sequence; a deletion that removes the bromodomain from the SPT7 protein causes no detectable mutant phenotype. Strains that contain an spt7 null mutation are viable but grow very slowly and have transcriptional defects at many loci including insertion mutations, Ty elements, the INO1 gene and the MFA1 gene. These transcriptional defects and other mutant phenotypes are similar to those caused by certain mutations in SPT15, which encodes the TATA binding protein (TBP). The similarity of the phenotypes of spt7 and spt15 mutants, including effects of spt7 mutations on the transcription start site of certain genes, suggests that SPT7 plays an important role in transcription initiation in vivo.


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