Transferring chromosome DNA fragments from multiple donor cells into a host strain for yeast strain improvement

2012 ◽  
Vol 58 (6) ◽  
pp. 760-766 ◽  
Author(s):  
Xian’ai Shi ◽  
Hang Wang ◽  
Hao Wang ◽  
Zhiming Wang ◽  
Chun Meng
Keyword(s):  
Strain Improvement ◽  
Temperature Tolerance ◽  
Host Strain ◽  
Dna Fragments ◽  
Chromosomal Dna ◽  
Donor Cells ◽  
Donor Chromosome ◽  
Novel Method ◽  
Multiple Strains ◽  
Positive Traits

Based on a common biological phenomenon — homologous recombination — a novel method was developed by transferring chromosome DNA fragments extracted from multiple donor cells into a host strain. Through this method of transferring DNA fragments, foreign DNA fragments are introduced into one host cell and multiple positive traits from multiple strains may be integrated into the host strain. We first confirmed its feasibility in both prokaryotic and eukaryotic cells by selecting reverse mutants to prototrophy from auxotrophic strains through receiving chromosomal DNA fragments of wild-type parental strains. We then applied this method to Saccharomyces cerevisiae to improve its ethanol and temperature tolerance. We introduced donor chromosome DNA fragments from different S. cerevisiae strains with improvements in ethanol or temperature tolerance into a common strain S. cerevisiae and obtained a strain with much superior ethanol and temperature tolerance. The results showed that the Transferring DNA Fragments method provides a new way for strain breeding.

Effects of mutation position on frequency of marker rescue by homologous recombination

1992 ◽  
Vol 12 (8) ◽  
pp. 3609-3613
Author(s):  
L Jiang ◽  
A Connor ◽  
M J Shulman
Keyword(s):  
Homologous Recombination ◽  
Normal Function ◽  
Constant Region ◽  
Dna Fragments ◽  
Wild Type ◽  
End Effect ◽  
Chromosomal Dna ◽  
Base Pairs ◽  
Marker Rescue ◽  
Immunoglobulin Mu

Homologous recombination between transferred and chromosomal DNA can be used for mapping mutations by marker rescue, i.e., by identifying which segment of wild-type DNA can recombine with the mutant chromosomal gene and restore normal function. In order to define how much the fragments should overlap each other for reliable mapping, we have measured how the frequency of marker rescue is affected by the position of the chromosomal mutation relative to the ends of the transferred DNA fragments. For this purpose, we used several DNA fragments to effect marker rescue in two mutant hybridomas which bear mutations 673 bp apart in the exons encoding the second and third constant region domains of the immunoglobulin mu heavy chain. The frequency of marker rescue decreased greatly when the mutation was located near one of the ends of the fragments, the results indicating that fragments should be designed to overlap by at least several hundred base pairs. Possible explanations for this "end effect" are considered.

Development of a fungal transformation system based on selection of sequences with promoter activity

1987 ◽  
Vol 7 (9) ◽  
pp. 3297-3305
Author(s):  
B G Turgeon ◽  
R C Garber ◽  
O C Yoder
Keyword(s):  
Genomic Dna ◽  
Pathogenic Fungus ◽  
Low Frequency ◽  
Hygromycin B ◽  
Fungal Transformation ◽  
Dna Fragments ◽  
Transformation System ◽  
Chromosomal Dna ◽  
General Utility ◽  
Novel Strategy

A novel strategy was used to develop a transformation system for the plant pathogenic fungus Cochliobolus heterostrophus. Sequences capable of driving the expression of a gene conferring resistance to the antibiotic hygromycin B in C. heterostrophus were selected from a library of genomic DNA fragments and used, with the selectable marker, as the basis for transformation. The library of random 0.5- to 2.0-kilobase-pair fragments of C. heterostrophus genomic DNA was inserted at the 5' end of a truncated, promoterless Escherichia coli hygromycin B phosphotransferase gene (hygB) whose product confers resistance to hygromycin B. C. heterostrophus protoplasts were transformed with the library and selected for resistance. Resistant colonies arose at low frequency. Each colony contained a transformation vector stably integrated into chromosomal DNA. When the transforming DNA was recovered from the genome and introduced into C. heterostrophus, resistant colonies appeared at higher frequency. We determined the sequences of two of the C. heterostrophus DNA fragments which had been inserted at the 5' end of hygB in the promoter library and found that both made translational fusions with hygB. One of the two fusions apparently adds 65 and the other at least 86 amino acids to the N-terminus of the hygB product. Plasmids containing hygB-C. heterostrophus promoter fusions can be used unaltered to drive hygB expression in several other filamentous ascomycetes. This approach to achieving transformation may have general utility, especially for organisms with relatively undeveloped genetics.

scholarly journals Measurement of transcribed human X-chromosomal DNA sequences transferred to rodent cells by chromosome-mediated gene transfer.

1982 ◽  
Vol 2 (1) ◽  
pp. 52-65 ◽  
Author(s):  
O W McBride ◽  
A S Olsen ◽  
G S Aulakh ◽  
R S Athwal
Keyword(s):  
Dna Sequences ◽  
Genetic Information ◽  
Hybrid Cell ◽  
Single Copy ◽  
Nucleic Acid Hybridization ◽  
Chromosomal Dna ◽  
Metaphase Chromosomes ◽  
Transfer Event ◽  
Donor Chromosome ◽  
Labeled Probe

Transfer of genetic information can be effected by incubation of cultured eucaryotic cells with isolated metaphase chromosomes. In most cases, a resulting transformed cell contains only a fragment of a donor chromosome. The amount of transferred donor DNA has been quantified in 11 independent mouse A9 transformants by nucleic acid hybridization analysis. Each transformant had been selected for hprt (hypoxanthine phosphoribosyltransferase; EC 2.4.2.8) transfer and contained part of the human X chromosome. A labeled probe of transcribed human X-chromosomal DNA was prepared by hybridization of nick-translated unique-sequence human DNA with whole cellular RNA from a human-mouse hybrid cell line, A9/HRBC2-A, containing a single human chromosome., X. The amount of human X-chromosomal DNA in the transformants was quantitated by comparing the hybridization of this probe with transformant and A9/HRBC2-A DNAs. Two unstable transformants which had a microscopically detectable donor chromosome fragment contained 15% of the human X-chromosomal single-copy DNA. Four other unstable transformants contained 4 to 7% of human X-chromosomal DNA sequences. The transferred DNA was below the level of detection in three other unstable and in all three stable transformants. We conclude that the initial transfer event can introduce a substantial amount of genetic information but only smaller amounts of DNA are stably incorporated by integration.

scholarly journals Development of a fungal transformation system based on selection of sequences with promoter activity.

1987 ◽  
Vol 7 (9) ◽  
pp. 3297-3305 ◽  
Author(s):  
B G Turgeon ◽  
R C Garber ◽  
O C Yoder
Keyword(s):  
Genomic Dna ◽  
Pathogenic Fungus ◽  
Low Frequency ◽  
Hygromycin B ◽  
Fungal Transformation ◽  
Dna Fragments ◽  
Transformation System ◽  
Chromosomal Dna ◽  
General Utility ◽  
Novel Strategy

A novel strategy was used to develop a transformation system for the plant pathogenic fungus Cochliobolus heterostrophus. Sequences capable of driving the expression of a gene conferring resistance to the antibiotic hygromycin B in C. heterostrophus were selected from a library of genomic DNA fragments and used, with the selectable marker, as the basis for transformation. The library of random 0.5- to 2.0-kilobase-pair fragments of C. heterostrophus genomic DNA was inserted at the 5' end of a truncated, promoterless Escherichia coli hygromycin B phosphotransferase gene (hygB) whose product confers resistance to hygromycin B. C. heterostrophus protoplasts were transformed with the library and selected for resistance. Resistant colonies arose at low frequency. Each colony contained a transformation vector stably integrated into chromosomal DNA. When the transforming DNA was recovered from the genome and introduced into C. heterostrophus, resistant colonies appeared at higher frequency. We determined the sequences of two of the C. heterostrophus DNA fragments which had been inserted at the 5' end of hygB in the promoter library and found that both made translational fusions with hygB. One of the two fusions apparently adds 65 and the other at least 86 amino acids to the N-terminus of the hygB product. Plasmids containing hygB-C. heterostrophus promoter fusions can be used unaltered to drive hygB expression in several other filamentous ascomycetes. This approach to achieving transformation may have general utility, especially for organisms with relatively undeveloped genetics.

Horizontal Acquisition of Divergent Chromosomal DNA in Bacteria: Effects of Mutator Phenotypes

Genetics ◽  
2003 ◽  
Vol 164 (1) ◽  
pp. 13-21
Author(s):  
Jeffrey P Townsend ◽  
Kaare M Nielsen ◽  
Daniel S Fisher ◽  
Daniel L Hartl
Keyword(s):  
Amino Acid ◽  
Genetic Variability ◽  
Environmental Dna ◽  
Fold Increase ◽  
Dna Fragments ◽  
Chromosomal Dna ◽  
Bacterial Populations ◽  
E Coli ◽  
Beneficial Effects ◽  
Acid Protein

Abstract We examine the potential beneficial effects of the expanded access to environmental DNA offered by mutators on the adaptive potential of bacterial populations. Using parameters from published studies of recombination in E. coli, we find that the presence of mutators has the potential to greatly enhance bacterial population adaptation when compared to populations without mutators. In one specific example, for which three specific amino acid substitutions are required for adaptation to occur in a 300-amino-acid protein, we found a 3500-fold increase in the rate of adaptation. The probability of a beneficial acquisition decreased if more amino acid changes, or integration of longer DNA fragments, were required for adaptation. The model also predicts that mutators are more likely than nonmutator phenotypes to acquire genetic variability from a more diverged set of donor bacteria. Bacterial populations harboring mutators in a sequence heterogeneous environment are predicted to acquire most of their DNA conferring adaptation in the range of 13–30% divergence, whereas nonmutator phenotypes become adapted after recombining with more homogeneous sequences of 7–21% divergence. We conclude that mutators can accelerate bacterial adaptation when desired genetic variability is present within DNA fragments of up to ∼30% divergence.

The use of male-specific chromosomal DNA fragments to determine the sex of bovine preimplantation embryos

1989 ◽  
Vol 31 (1) ◽  
pp. 95-104 ◽  
Author(s):  
K.R. Bondioli ◽  
S.B. Ellis ◽  
J.H. Pryor ◽  
M.W. Williams ◽  
M.M. Harpold
Keyword(s):  
Preimplantation Embryos ◽  
Dna Fragments ◽  
Chromosomal Dna ◽  
Male Specific

Chromosomol DNA fragments from mouse cells exposed to an intercalating agent contain a 175-kdalton terminal polypeptide

1985 ◽  
Vol 63 (7) ◽  
pp. 780-783 ◽  
Author(s):  
Ray K. Ralph ◽  
Ronald Hancock
Keyword(s):  
Electron Microscopy ◽  
Molecular Mass ◽  
Topoisomerase Ii ◽  
Relative Molecular Mass ◽  
Dna Fragments ◽  
Torsional Stress ◽  
Chromosomal Dna ◽  
Terminal Protein ◽  
Mouse Cells ◽  
Polypeptide Chains

A 175 kdalton (kDa) polypeptide is bound covalently to the chromosomal DNA fragments from mouse cells exposed to the intercalating agent 4′-[(9-acridinyl)-amino]methansulphon-m-anisidide. Electron microscopy shows a terminal protein on the DNA fragments, whose 5′-termini are blocked. Since the relative molecular mass of topoisomerase II polypeptide chains is also about 175 kDa and topoisomerase II inhibitors prevent intercalator-induced DNA fragmentation, we propose that the polypeptide bound covalently to the 5′-terminus of the DNA fragments is a polypeptide derived from frequently integrated topoisomerase II operating to normalize torsional stress resulting from intercalation.

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