2-Dodecylcyclobutanone Does Not Induce Mutations in the Salmonella Mutagenicity Test or Intrachromosomal Recombination in Saccharomyces cerevisiae†

2004 ◽  
Vol 67 (6) ◽  
pp. 1293-1298 ◽  
Author(s):  
CHRISTOPHER H. SOMMERS ◽  
ROBERT H. SCHIESTL
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Metabolic Activation ◽  
Microtiter Plate ◽  
Laboratory Animals ◽  
Radiolytic Product ◽  
Mutagenicity Test ◽  
Intrachromosomal Recombination ◽  
Irradiated Foods ◽  
Exogenous Metabolic Activation ◽  
His3 Gene

Treatment of foods, such as red meat and poultry, that contain palmitic acid with ionizing radiation leads to the formation of 2-dodecylcyclobutanone (2-DCB), a compound found only in irradiated foods. In this study, the Salmonella mutagenicity test and the yeast DEL assay were used to evaluate the genotoxic potential of 2-DCB. Salmonella Typhimurium tester strains TA98, TA100, TA1535, and TA1537 were exposed to 0, 0.125, 0.25, 0.5, and 1 mg per well of 2-DCB, with and without exogenous metabolic activation (5% S9 fraction), using the microtiter plate–based Miniscreen version of the test. 2-DCB did not induce mutations in the Salmonella mutagenicity test. When Saccharomyces cerevisiae strain RS112, which contains a nonfunctional duplication of the his3 gene that can be induced to form a functional HIS3+ gene by intrachromosomal recombination, was exposed to 0.63, 1.25, 2.5, or 5.0 mg/ml of 2-DCB, no increase in the rate of intrachromosomal (DEL) recombination was observed. The absence of genotoxicity observed in this study using purified 2-DCB agrees with the lack of genotoxic and teratogenic activity observed in previously conducted multigeneration feeding studies of laboratory animals (rats, mice, guinea pigs, and rabbits) that used radiation-sterilized poultry that contained 2-DCB as a unique radiolytic product.

Proline utilization in Saccharomyces cerevisiae: analysis of the cloned PUT2 gene

1983 ◽  
Vol 3 (10) ◽  
pp. 1846-1856
Author(s):  
M C Brandriss
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Recombinant Dna ◽  
Fold Increase ◽  
Activity Levels ◽  
Mrna Levels ◽  
S1 Nuclease ◽  
Proline Utilization ◽  
Cloned Gene ◽  
His3 Gene ◽  
Specific Mrna

The PUT2 gene was isolated on a 6.5-kilobase insert of a recombinant DNA plasmid by functional complementation of a put2 (delta 1-pyrroline-5-carboxylate dehydrogenase-deficient) mutation in Saccharomyces cerevisiae. Its identity was confirmed by a gene disruption technique in which the chromosomal PUT2+ gene was replaced by plasmid DNA carrying the put2 gene into which the S. cerevisiae HIS3+ gene had been inserted. The cloned PUT2 gene was used to probe specific mRNA levels: full induction of the PUT2 gene resulted in a 15-fold increase over the uninduced level. The PUT2-specific mRNA was approximately 2 kilobases in length and was used in S1 nuclease protection experiments to locate the gene to a 3-kilobase HindIII fragment. When delta 1-pyrroline-5-carboxylate dehydrogenase activity levels were measured in strains carrying the original plasmid, as well as in subclones, similar induction ratios were found as compared with enzyme levels in haploid yeast strains. Effects due to increased copy number or position were also seen. The cloned gene on a 2 mu-containing vector was used to map the PUT2 gene to chromosome VIII.

Suppressors of Saccharomyces cerevisiae his3 promoter mutations lacking the upstream element

1985 ◽  
Vol 5 (8) ◽  
pp. 1901-1909
Author(s):  
M A Oettinger ◽  
K Struhl
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transcriptional Activation ◽  
Tata Box ◽  
Micrococcal Nuclease ◽  
Promoter Element ◽  
Wild Type ◽  
Upstream Promoter ◽  
In The Wild ◽  
Promoter Mutations ◽  
His3 Gene

Transcription of the Saccharomyces cerevisiae his3 gene requires an upstream promoter element and a TATA element. A strain containing his3-delta 13, an allele which deletes the upstream promoter element but contains the TATA box and intact structural gene, fails to express the gene and consequently is unable to grow in medium lacking histidine. In this paper we characterize His+ revertants of his3-delta 13 which are due to unlinked suppressor mutations. Recessive suppressors in three different ope genes allow his3-delta 13 to be expressed at wild-type levels. In all cases, the suppression is due to increased his3 transcription. However, unlike the wild-type his3 gene, whose transcripts are initiated about equally from two different sites (+1 and +12), transcription due to the ope mutations is initiated only from the +12 site, ope-mediated transcription is regulated in a novel manner; it is observed in minimal medium, but not in rich broth. Although ope mutations restore wild-type levels of transcription, his3 chromatin structure, as assayed by micrococcal nuclease sensitivity of the TATA box, resembles that found in the his3-delta 13 parent rather than in the wild-type strain. This provides further evidence that TATA box sensitivity is not correlated with transcriptional activation. ope mutations are pleiotropic in that cells have a crunchy colony morphology and lyse at 37 degrees C in conditions of normal osmolarity. ope mutations are allele specific because they fail to suppress five other his3 promoter mutations. We discuss implications concerning upstream promoter elements and propose some models for ope suppression.

Interchromosomal and intrachromosomal recombination in rad 18 mutants of Saccharomyces cerevisiae

1990 ◽  
Vol 222 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Robert H. Schiestl ◽  
R. Daniel Gietz ◽  
P. J. Hastings ◽  
Ulrike Wintersberger
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Intrachromosomal Recombination

Direction of chromosome rearrangements in Saccharomyces cerevisiae by use of his3 recombinational substrates

1988 ◽  
Vol 8 (10) ◽  
pp. 4370-4380
Author(s):  
M T Fasullo ◽  
R W Davis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Chromosomal Dna ◽  
Yeast Saccharomyces Cerevisiae ◽  
Coding Sequences ◽  
Mutant Strains ◽  
Genetic Techniques ◽  
Orthogonal Field ◽  
His3 Gene ◽  
Tandem Duplications

We used the his3 recombinational substrates (his3 fragments) to direct large interchromosomal (translocations) and intrachromosomal (deletions and tandem duplications) rearrangements in the yeast Saccharomyces cerevisiae. In strains completely deleted for the wild-type HIS3 gene, his3 fragments, one containing a deletion of 5' amino acid coding sequences and the other containing a deletion of 3' amino acid coding sequences, were first placed at preselected sites by homologous recombination. His+ revertants that arose via spontaneous mitotic recombination between the two his3 fragments were selected. This strategy was used to direct rearrangements in both RAD52+ and rad52 mutant strains. Translocations occurred in the RAD52+ genetic background and were characterized by orthogonal field alternating gel electrophoresis of yeast chromosomal DNA and by standard genetic techniques. An unexpected translocation was also identified in which HIS3 sequences were amplified. Two types of tandem duplications of the GAL(7, 10, 1) locus were also directed, and one type was not observed in rad52 mutants. Recombination mechanisms are discussed to account for these differences.

Effect of limited homology on gene conversion in a Saccharomyces cerevisiae plasmid recombination system

1988 ◽  
Vol 8 (6) ◽  
pp. 2442-2448 ◽  
Author(s):  
B Y Ahn ◽  
K J Dornfeld ◽  
T J Fagrelius ◽  
D M Livingston
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Gene Conversion ◽  
Dna Sequences ◽  
Homologous Sequence ◽  
Insertion Mutation ◽  
Base Pairs ◽  
Recombination System ◽  
Plasmid Recombination ◽  
His3 Gene ◽  
Conversion Tract

Plasmids containing heteroallelic copies of the Saccharomyces cerevisiae HIS3 gene undergo intramolecular gene conversion in mitotically dividing S. cerevisiae cells. We have used this plasmid system to determine the minimum amount of homology required for gene conversion, to examine how conversion tract lengths are affected by limited homology, and to analyze the role of flanking DNA sequences on the pattern of exchange. Plasmids with homologous sequences greater than 2 kilobases have mitotic exchange rates as high as 2 x 10(-3) events per cell per generation. As the homology is reduced, the exchange rate decreases dramatically. A plasmid with 26 base pairs (bp) of homology undergoes gene conversion at a rate of approximately 1 x 10(-10) events per cell per generation. These studies have also shown that an 8-bp insertion mutation 13 bp from a border between homologous and nonhomologous sequences undergoes conversion, but that a similar 8-bp insertion 5 bp from a border does not. Examination of independent conversion events which occurred in plasmids with heteroallelic copies of the HIS3 gene shows that markers within 280 bp of a border between homologous and nonhomologous sequences undergo conversion less frequently than the same markers within a more extensive homologous sequence. Thus, proximity to a border between homologous and nonhomologous sequences shortens the conversion tract length.

scholarly journals Sequences that regulate the divergent GAL1-GAL10 promoter in Saccharomyces cerevisiae.

1984 ◽  
Vol 4 (8) ◽  
pp. 1440-1448 ◽  
Author(s):  
M Johnston ◽  
R W Davis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nucleotide Sequence ◽  
Base Pair ◽  
Transcription Initiation ◽  
Base Pairs ◽  
Regulation Of Expression ◽  
Notable Feature ◽  
His3 Gene

The GAL1 and GAL10 genes of Saccharomyces cerevisiae are divergently transcribed, with 606 base pairs of DNA separating their transcription initiation sites. These two genes are stringently coregulated: their expression is induced ca. 1,000-fold in cells growing on galactose and is repressed by growth on glucose. The nucleotide sequence of the region of DNA between these genes and the precise sites of transcription initiation are presented here. The most notable feature of the nucleotide sequence of this region is a 108-base-pair guanine-plus-cytosine-rich stretch of DNA located approximately in the middle of the region between GAL1 and GAL10. Analysis of the effects of mutations that alter the region between these two genes, constructed in vitro or selected in vivo, suggest that these guanine-plus-cytosine-rich sequences are required for the expression of both genes. The region of DNA between GAL1 and GAL10 is sufficient for regulation of expression of these genes: fusion of the region to the yeast HIS3 gene places HIS3 under GAL control.

scholarly journals Suppressors of Saccharomyces cerevisiae his3 promoter mutations lacking the upstream element.

1985 ◽  
Vol 5 (8) ◽  
pp. 1901-1909 ◽  
Author(s):  
M A Oettinger ◽  
K Struhl
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Transcriptional Activation ◽  
Tata Box ◽  
Micrococcal Nuclease ◽  
Promoter Element ◽  
Wild Type ◽  
Upstream Promoter ◽  
In The Wild ◽  
Promoter Mutations ◽  
His3 Gene

Transcription of the Saccharomyces cerevisiae his3 gene requires an upstream promoter element and a TATA element. A strain containing his3-delta 13, an allele which deletes the upstream promoter element but contains the TATA box and intact structural gene, fails to express the gene and consequently is unable to grow in medium lacking histidine. In this paper we characterize His+ revertants of his3-delta 13 which are due to unlinked suppressor mutations. Recessive suppressors in three different ope genes allow his3-delta 13 to be expressed at wild-type levels. In all cases, the suppression is due to increased his3 transcription. However, unlike the wild-type his3 gene, whose transcripts are initiated about equally from two different sites (+1 and +12), transcription due to the ope mutations is initiated only from the +12 site, ope-mediated transcription is regulated in a novel manner; it is observed in minimal medium, but not in rich broth. Although ope mutations restore wild-type levels of transcription, his3 chromatin structure, as assayed by micrococcal nuclease sensitivity of the TATA box, resembles that found in the his3-delta 13 parent rather than in the wild-type strain. This provides further evidence that TATA box sensitivity is not correlated with transcriptional activation. ope mutations are pleiotropic in that cells have a crunchy colony morphology and lyse at 37 degrees C in conditions of normal osmolarity. ope mutations are allele specific because they fail to suppress five other his3 promoter mutations. We discuss implications concerning upstream promoter elements and propose some models for ope suppression.

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