scholarly journals Industrial yeasts display tandem gene iteration at the CUP1 region.

1983 ◽  
Vol 3 (8) ◽  
pp. 1353-1361 ◽  
Author(s):  
J W Welch ◽  
S Fogel ◽  
G Cathala ◽  
M Karin

The gene copy number at the CUP1 locus and the resistance level to external copper was directly correlated in five wild-type commercial Saccharomyces strains. An increased copy number of the CUP1 gene leads to increased accumulation of chelatin mRNA, which codes for a low-molecular-weight, copper-binding protein. The enhanced production of this rapidly inducible protein mediates resistance of the cell to copper. Industrial yeasts exhibit homologies to the amplified copper resistance repeat unit found in laboratory strains. However, the extent of tandem iteration is strain dependent, and the repetitious unit is either 1.7 or 1.5 kilobases in length compared with the 2.0-kilobase unit in laboratory strains. Strain 522 (Montrachet) contains two chromosome VIII segments distinguishable by their numbers of repeat units (2 and 11) and the size of the units (1.5 and 1.7 kilobases). Distillers yeast 513 carries a 1.5-kilobase repeat unit on each homologous chromosome, although they contain nine and five iterations, respectively.

1983 ◽  
Vol 3 (8) ◽  
pp. 1353-1361
Author(s):  
J W Welch ◽  
S Fogel ◽  
G Cathala ◽  
M Karin

The gene copy number at the CUP1 locus and the resistance level to external copper was directly correlated in five wild-type commercial Saccharomyces strains. An increased copy number of the CUP1 gene leads to increased accumulation of chelatin mRNA, which codes for a low-molecular-weight, copper-binding protein. The enhanced production of this rapidly inducible protein mediates resistance of the cell to copper. Industrial yeasts exhibit homologies to the amplified copper resistance repeat unit found in laboratory strains. However, the extent of tandem iteration is strain dependent, and the repetitious unit is either 1.7 or 1.5 kilobases in length compared with the 2.0-kilobase unit in laboratory strains. Strain 522 (Montrachet) contains two chromosome VIII segments distinguishable by their numbers of repeat units (2 and 11) and the size of the units (1.5 and 1.7 kilobases). Distillers yeast 513 carries a 1.5-kilobase repeat unit on each homologous chromosome, although they contain nine and five iterations, respectively.


2016 ◽  
Author(s):  
Todd A. Gaines ◽  
Abigail L. Barker ◽  
Eric L. Patterson ◽  
Philip Westra ◽  
Eric P. Westra ◽  
...  

AbstractGlyphosate-resistant (GR) Kochia scoparia has evolved in dryland chemical fallow systems throughout North America and the mechanism involves 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene duplication. Sugarbeet fields in four states were surveyed for K. scoparia in 2013 and tested for glyphosate-resistance level and EPSPS gene copy number. Glyphosate resistance was confirmed in K. scoparia populations collected from sugarbeet fields in Colorado, Wyoming, and Nebraska. The GR samples all had increased EPSPS gene copy number, with median population values up to 11. An empirical model was developed to estimate the level of glyphosate-resistance in K. scoparia based on EPSPS gene copy number. The results suggested that glyphosate susceptibility can be accurately diagnosed using EPSPS gene copy number, and further increases in EPSPS gene copy number could increase resistance levels up to 8-fold relative to susceptible K. scoparia. These trends suggest that continued glyphosate selection pressure is selecting for higher EPSPS copy number and higher resistance levels in K. scoparia. By including multiple K. scoparia samples lacking EPSPS gene duplication, our empirical model provides a more realistic estimate of fold-resistance due to EPSPS gene copy number compared to methods that do not account for normal variation of herbicide response in susceptible biotypes.


2019 ◽  
Author(s):  
Ryan Hull ◽  
Michelle King ◽  
Grazia Pizza ◽  
Felix Krueger ◽  
Xabier Vergara ◽  
...  

Extrachromosomal circular DNA (eccDNA) facilitates adaptive evolution by allowing rapid and extensive gene copy number variation, and is implicated in the pathology of cancer and ageing. Here, we demonstrate that yeast aged under environmental copper accumulate high levels of eccDNA containing the copper resistance gene CUP1. Transcription of CUP1 causes CUP1 eccDNA accumulation, which occurs in the absence of phenotypic selection. We have developed a sensitive and quantitative eccDNA sequencing pipeline that reveals CUP1 eccDNA accumulation on copper exposure to be exquisitely site specific, with no other detectable changes across the eccDNA complement. eccDNA forms de novo from the CUP1 locus through processing of DNA double-strand breaks (DSBs) by Sae2 / Mre11 and Mus81, and genome-wide analyses show that other protein coding eccDNA species in aged yeast share a similar biogenesis pathway. Although abundant we find that CUP1 eccDNA does not replicate efficiently, and high copy numbers in aged cells arise through frequent formation events combined with asymmetric DNA segregation. The transcriptional stimulation of CUP1 eccDNA formation shows that age-linked genetic change varies with transcription pattern, resulting in gene copy number profiles tailored by environment.


2017 ◽  
Vol 32 (1) ◽  
pp. 27-33 ◽  
Author(s):  
Vipan Kumar ◽  
Joel Felix ◽  
Don Morishita ◽  
Prashant Jha

AbstractGlyphosate-resistant (GR) kochia is an increasing management concern in major cropping systems of the northwestern US. In 2014, we investigated four putative GR kochia accessions (designated as ALA, VAL, WIL, DB) collected from sugar beet fields in eastern Oregon and southwestern Idaho to characterize the level of evolved glyphosate resistance and determine the relationship between the 5-enol-pyruvylshikimate-3-phospate synthase (EPSPS) gene copy number and level of glyphosate resistance. TheEPSPSgene copy number was used as a molecular marker to detect GR kochia in subsequent surveys in 2015 and 2016. Based on LD50values from a whole-plant dose-response study, the four putative GR kochia populations were 2.0- to 9.6-fold more resistant to glyphosate than the glyphosate-susceptible (GS) accession. In anin vivoleaf-disk shikimate assay, leaf disks of GS kochia plants treated with 100-μM glyphosate accumulated 2.4- to 4.0-fold higher amounts of shikimate than the GR plants. The four GR accessions had 2.7 to 9.1 relativeEPSPSgene copies compared with the GS accession (<1EPSPSgene copies), and there was a linear relationship betweenEPSPSgene copy number and glyphosate resistance level (LD50values). The 2015 and 2016 GR kochia survey results indicated that about half of the collected populations from sugar beet fields in eastern Oregon had developed resistance to glyphosate whereas only one population from the Idaho collection was confirmed glyphosate resistant. This is the first confirmation of GR kochia in sugar beet fields in eastern Oregon and southwestern Idaho. Diversified weed control programs will be required to prevent further development and spread of GR kochia in sugar beet-based rotations in this region.


PLoS ONE ◽  
2016 ◽  
Vol 11 (12) ◽  
pp. e0168295 ◽  
Author(s):  
Todd A. Gaines ◽  
Abigail L. Barker ◽  
Eric L. Patterson ◽  
Philip Westra ◽  
Eric P. Westra ◽  
...  

Weed Science ◽  
2018 ◽  
Vol 66 (3) ◽  
pp. 293-300 ◽  
Author(s):  
Shilpa Singh ◽  
Vijay Singh ◽  
Amy Lawton-Rauh ◽  
Muthukumar V. Bagavathiannan ◽  
Nilda Roma-Burgos

AbstractResearch was conducted to determine whether resistance to glyphosate among Palmer amaranth (Amaranthus palmeriS. Watson) populations within the U.S. state of Arkansas was due solely to increasedEPSPSgene copy number and whether gene copy number is correlated with resistance level to glyphosate. One hundred and fifteenA. palmeriaccessions were treated with 840 g ae ha−1glyphosate. Twenty of these accessions, selected to represent a broad range of responses to glyphosate, underwent further testing. Seven of the accessions were controlled with this dose; the rest were resistant. The effective dose to cause 50% injury (ED50) for susceptible accessions ranged from 28 to 207 g ha−1. The glyphosate-resistant (GR) accessions had ED50values ranging from 494 to 1,355 g ha−1, a 3- to 48-fold resistance level compared with the susceptible standard (SS). The 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene relative copy number was determined for 20 accessions, 4 plants accession−1. Resistant plants from five GR accessions (38% of resistant plants tested) did not have increasedEPSPSgene copies. Resistant plants from the remaining eight GR accessions (62% of resistant plants tested) had 19 to 224 moreEPSPSgene copies than the SS. Among the accessions tested, injury declined 4% with every additionalEPSPScopy. ED50values were directly correlated withEPSPScopy number. The highly resistant accession MIS11-B had an ED50of 1,355 g ha−1and 150 gene copies. Partial sequences ofEPSPSfrom GR accessions withoutEPSPSamplification did not contain any of the known resistance-conferring mutations. Nearly 40% of GR accessions putatively harbor non–target site resistance mechanisms. Therefore, elevatedEPSPSgene copy number is associated with glyphosate resistance amongA. palmerifrom Arkansas.


Genes ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 283
Author(s):  
Eyal Seroussi

Determination of the relative copy numbers of mixed molecular species in nucleic acid samples is often the objective of biological experiments, including Single-Nucleotide Polymorphism (SNP), indel and gene copy-number characterization, and quantification of CRISPR-Cas9 base editing, cytosine methylation, and RNA editing. Standard dye-terminator chromatograms are a widely accessible, cost-effective information source from which copy-number proportions can be inferred. However, the rate of incorporation of dye terminators is dependent on the dye type, the adjacent sequence string, and the secondary structure of the sequenced strand. These variable rates complicate inferences and have driven scientists to resort to complex and costly quantification methods. Because these complex methods introduce their own biases, researchers are rethinking whether rectifying distortions in sequencing trace files and using direct sequencing for quantification will enable comparable accurate assessment. Indeed, recent developments in software tools (e.g., TIDE, ICE, EditR, BEEP and BEAT) indicate that quantification based on direct Sanger sequencing is gaining in scientific acceptance. This commentary reviews the common obstacles in quantification and the latest insights and developments relevant to estimating copy-number proportions based on direct Sanger sequencing, concluding that bidirectional sequencing and sophisticated base calling are the keys to identifying and avoiding sequence distortions.


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