Use of interplasmid recombination to generate stable selectable markers for yeast transformation: application to studies of actin gene control

Genome ◽  
1990 ◽  
Vol 33 (5) ◽  
pp. 696-706 ◽  
Author(s):  
Andrew V. Hubberstey ◽  
Alan G. Wildeman
Keyword(s):  
Blot Analysis ◽  
Actin Gene ◽  
Multicopy Plasmid ◽  
Recombinant Plasmids ◽  
Leu2 Gene ◽  
Recombination System ◽  
Plasmid Recombination ◽  
Intact Gene ◽  
Multiple Copies ◽  
2 Μm Plasmid

A plasmid recombination system has been developed that relies upon interplasmid exchanges for yeast cell viability. Two types of plasmids, one carrying the LEU2 allele inserted within yeast actin gene sequences and the other carrying 2-μm plasmid DNA and an intact actin gene, were constructed. Neither plasmid alone yielded transformants in the haploid Leu− strain AH22, but when cotransformed, a number of colonies were obtained. Southern blot analysis revealed that transformants arose because of recombination events within the homologous actin sequences that transferred the LEU2 gene to the actin gene on the 2-μm plasmid. The recombinant plasmids could be recovered, and sequence analysis of one recombination site revealed that the exchange event was faithful at the nucleotide level. The resulting recombinant plasmids carried a defective actin gene and presumably arose because of a double-crossover event. Deletion mutations that prevented actin gene expression on one donor plasmid enabled the recovery at a high frequency of transformants resulting primarily from single-crossover events between the two plasmids. This was presumably because such events no longer generated an intact actin gene on a multicopy plasmid. Infrequently a transformant from a plasmid with an intact gene was recovered, but in these cases the plasmid was not present in multiple copies. These cells exhibited a slower growth rate, and Northern blot analysis revealed an elevated level of actin mRNA.Key words: homologous recombination, regulation, gene disruption, tranformation, actin.

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 Cloning and characterization of FAD1, the structural gene for flavin adenine dinucleotide synthetase of Saccharomyces cerevisiae.

1995 ◽  
Vol 15 (1) ◽  
pp. 264-271 ◽  
Author(s):  
M Wu ◽  
B Repetto ◽  
D M Glerum ◽  
A Tzagoloff
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Flavin Adenine Dinucleotide ◽  
Genomic Library ◽  
Sequence Similarity ◽  
Complementation Group ◽  
Flavin Mononucleotide ◽  
Synthetase Activity ◽  
Multicopy Plasmid ◽  
Multiple Copies ◽  
Extragenic Suppression

The FAD1 gene of Saccharomyces cerevisiae has been selected from a genomic library on the basis of its ability to partially correct the respiratory defect of pet mutants previously assigned to complementation group G178. Mutants in this group display a reduced level of flavin adenine dinucleotide (FAD) and an increased level of flavin mononucleotide (FMN) in mitochondria. The restoration of respiratory capability by FAD1 is shown to be due to extragenic suppression. FAD1 codes for an essential yeast protein, since disruption of the gene induces a lethal phenotype. The FAD1 product has been inferred to be yeast FAD synthetase, an enzyme that adenylates FMN to FAD. This conclusion is based on the following evidence. S. cerevisiae transformed with FAD1 on a multicopy plasmid displays an increase in FAD synthetase activity. This is also true when the gene is expressed in Escherichia coli. Lastly, the FAD1 product exhibits low but significant primary sequence similarity to sulfate adenyltransferase, which catalyzes a transfer reaction analogous to that of FAD synthetase. The lower mitochondrial concentration of FAD in G178 mutants is proposed to be caused by an inefficient exchange of external FAD for internal FMN. This is supported by the absence of FAD synthetase activity in yeast mitochondria and the presence of both extramitochondrial and mitochondrial riboflavin kinase, the preceding enzyme in the biosynthetic pathway. A lesion in mitochondrial import of FAD would account for the higher concentration of mitochondrial FMN in the mutant if the transport is catalyzed by an exchange carrier. The ability of FAD1 to suppress impaired transport of FAD is explained by mislocalization of the synthetase in cells harboring multiple copies of the gene. This mechanism of suppression is supported by the presence of mitochondrial FAD synthetase activity in S. cerevisiae transformed with FAD1 on a high-copy-number plasmid but not in mitochondrial of a wild-type strain.

scholarly journals Organization and expression of multiple actin genes in the sea urchin.

1981 ◽  
Vol 1 (7) ◽  
pp. 609-628 ◽  
Author(s):  
R H Scheller ◽  
L B McAllister ◽  
W R Crain ◽  
D S Durica ◽  
J W Posakony ◽  
...  
Keyword(s):  
Sea Urchin ◽  
Deoxyribonucleic Acid ◽  
Repetitive Sequences ◽  
Actin Gene ◽  
Protein Coding ◽  
Messenger Ribonucleic Acid ◽  
Repeat Sequences ◽  
Actin Genes ◽  
Early Embryos ◽  
Multiple Copies

A set of at least 11 actin genes has been isolated from genomic recombinant deoxyribonucleic acid libraries of the sea urchin Strongylocentrotus purpuratus. Most of the isolates derive from a library which represents the genome of a single animal. There are at least five distinct types of sea urchin actin gene, some of which are represented by multiple copies in the genome. The actin gene types are distinguished by nonhomologous flanking sequences and intervening sequences, though the protein coding sequences appear in most cases to be quite similar. Eight of the 11 genes isolated have been recovered in lambda recombinants that contain two actin genes, linked at 5- to 9-kilobase distances. Restriction map overlaps suggest that the genome contains an array of at least three of these genes spaced over about 30 kilobases of deoxyribonucleic acid. In the linkage patterns observed, actin genes of diverse types were linked to each other. In early embryos, actin messenger ribonucleic acid (RNA) transcripts of 1.8 and 2.2 kilobases were found, and the longer of these transcripts was more prevalent in the maternal RNA of the egg. From RNA gel blot experiments, we conclude that the two transcripts derive from different actin gene types. Different repetitive sequences were located to either side of most of the actin genes, and in most observed cases the repeat sequences which were adjacent to actin genes of a given type were similar. The repeat sequences flanking the actin genes belonged to families which were transcribed, but those repeats in the neighborhood of the actin genes which have been investigated were not themselves represented in the stable RNAs of eggs or early embryos.

scholarly journals Actin genes in the Mediterranean fruit fly, Ceratitis capitata.

Genetics ◽  
1990 ◽  
Vol 125 (1) ◽  
pp. 155-160
Author(s):  
D S Haymer ◽  
J E Anleitner ◽  
M He ◽  
S Thanaphum ◽  
S H Saul ◽  
...  
Keyword(s):  
Ceratitis Capitata ◽  
Fruit Fly ◽  
Gene Organization ◽  
Mediterranean Fruit Fly ◽  
Actin Gene ◽  
Actin Genes ◽  
Wide Range ◽  
Multiple Copies ◽  
The Mediterranean ◽  
Eukaryotic Organisms

Abstract We have undertaken the study of actin gene organization and expression in the genome of the Mediterranean fruit fly (medfly), Ceratitis capitata. Actin genes have been extensively characterized previously in a wide range of eukaryotic organisms, and they have valuable properties for comparative studies. These genes are typically highly conserved in coding regions, represented in multiple copies per genome and regulated in expression during development. We have isolated a gene in the medfly using the cloned Drosophila melanogaster 5C actin gene as a probe. This medfly gene detects abundant messages present during late larval and late pupal development as well as in thoracic and leg tissue preparations from newly emerged adults. This pattern of expression is consistent with what has been seen for actin genes in other organisms. Using either the D. melanogaster 5C actin gene or the medfly gene as a probe identifies five common cross reacting EcoRI fragments in genomic DNA, but only under less than fully stringent hybridization conditions.

Cloning and analysis of the positively acting regulatory gene amdR from Aspergillus nidulans

1988 ◽  
Vol 8 (8) ◽  
pp. 3532-3541
Author(s):  
A Andrianopoulos ◽  
M J Hynes
Keyword(s):  
Aspergillus Nidulans ◽  
Blot Analysis ◽  
Regulatory Gene ◽  
Regulation Of Gene Expression ◽  
Strong Support ◽  
Cosmid Library ◽  
Loss Of Function ◽  
Structural Genes ◽  
Dna Rearrangements ◽  
Multiple Copies

The positively acting regulatory gene amdR of Aspergillus nidulans coordinately regulates the expression of four unlinked structural genes involved in acetamide (amdS), omega amino acid (gatA and gabA), and lactam (lamA) catabolism. By the use of DNA-mediated transformation of A. nidulans, the amdR regulatory gene was cloned from a genomic cosmid library. Southern blot analysis of DNA from various loss-of-function amdR mutants revealed the presence of four detectable DNA rearrangements, including a deletion, an insertion, and a translocation. No detectable DNA rearrangements were found in several constitutive amdRc mutants. Analysis of the fate of amdR-bearing plasmids in transformants showed that 10 to 20% of the transformation events were homologous integrations or gene conversions, and this phenomenon was exploited in developing a strategy by which amdRc and amdR- alleles can be readily cloned and analyzed. Examination of the transcription of amdR by Northern blot (RNA blot) analysis revealed the presence of two mRNAs (2.7 and 1.8 kilobases) which were constitutively synthesized at a very low level. In addition, amdR transcription did not appear to depend on the presence of a functional amdR product nor was it altered in amdRc mutants. The dosage effects of multiple copies of amdR in transformants were examined, and it was shown that such transformants exhibited stronger growth than did the wild type on acetamide and pyrrolidinone media, indicating increased expression of the amdS and lamA genes, respectively. These results were used to formulate a model for amdR-mediated regulation of gene expression in which the low constitutive level of amdR product sets the upper limits of basal and induced transcription of the structural genes. Multiple copies of 5' sequences from the amdS gene can result in reduced growth on substrates whose utilization is dependent on amdR-controlled genes. This has been attributed to titration of limiting amdR gene product. Strong support for this proposal was obtained by showing that multiple copies of the amdR gene can reverse this phenomenon (antititration).

Plasmid recombination intermediates generated in a Saccharomyces cerevisiae cell-free recombination system

1985 ◽  
Vol 5 (9) ◽  
pp. 2361-2368
Author(s):  
L S Symington ◽  
P Morrison ◽  
R Kolodner
Keyword(s):  
Electron Microscopy ◽  
Saccharomyces Cerevisiae ◽  
Electrophoretic Mobility ◽  
Electrophoretic Analysis ◽  
Individual Band ◽  
Agarose Gels ◽  
Cell Extracts ◽  
Recombination System ◽  
Plasmid Recombination

We have developed an assay utilizing Saccharomyces cerevisiae cell extracts to catalyze recombination in vitro between homologous plasmids containing different mutant alleles of the tet gene. Electrophoretic analysis of product DNA indicated that a number of novel DNA species were formed during the reaction. These species migrated through agarose gels as distinct bands with decreased electrophoretic mobility compared with the substrate DNA. The DNA from each individual band was purified and shown to be enriched 5- to 100-fold for tetracycline-resistant recombinants by using a transformation assay. The structure of the DNA molecules present in these bands was determined by electron microscopy. Recombination between circular substrates appeared to involve the formation and processing of figure-eight molecules, while recombination between circular and linear substrates involved the formation of molecules in which a circular monomer had a monomer-length linear tail attached at a region of homology.

The Saccharomyces cerevisiae ADR1 gene is a positive regulator of transcription of genes encoding peroxisomal proteins

1991 ◽  
Vol 11 (2) ◽  
pp. 699-704 ◽  
Author(s):  
M Simon ◽  
G Adam ◽  
W Rapatz ◽  
W Spevak ◽  
H Ruis
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Glucose Repression ◽  
Northern Hybridization ◽  
Multicopy Plasmid ◽  
Beta Oxidation ◽  
Positive Regulator ◽  
Ethanol Medium ◽  
Genes Encoding ◽  
Multiple Copies ◽  
Regulatory Functions

Expression of the CTA1 gene of Saccharomyces cerevisiae, encoding catalase A, the peroxisomal catalase of this yeast, is sensitive to glucose repression. A DNA fragment cloned as a multicopy plasmid suppressing the glucose repression of CTA1 transcription was demonstrated to contain the ADR1 gene. Multiple copies of ADR1 increased catalase A formation not only on 10% glucose, but also on ethanol medium and in the presence of oleic acid, an inducer of peroxisome proliferation. Compared with wild-type cells, adr1 null mutants produced by disruption of the gene exhibit reduced CTA1 expression. This demonstrates that ADR1 is a true positive regulator of CTA1. Further experiments showed that it acts directly on CTA1. Alcohol dehydrogenase II, which is under ADR1 control, was excluded as a mediator of the effect on CTA1; deletion of bases -123 to -168 of CTA1 reduces expression and eliminates the response to the ADR1 multicopy plasmid without eliminating fatty acid induction; and gel retardation experiments demonstrated that ADR1 binds to a CTA1 upstream fragment (-156 to -184) with limited similarity to the ADR1 binding site of ADH2. Northern hybridization experiments further demonstrated that expression of two genes encoding enzymes of peroxisomal beta-oxidation (beta-ketothiolase, trifunctional enzyme) and of a gene involved in peroxisome assembly (PAS1) is also negatively affected by the adr1 null mutation. These findings demonstrate that the ADR1 protein has much broader regulatory functions than previously recognized.

scholarly journals Cloning and analysis of the positively acting regulatory gene amdR from Aspergillus nidulans.

1988 ◽  
Vol 8 (8) ◽  
pp. 3532-3541 ◽  
Author(s):  
A Andrianopoulos ◽  
M J Hynes
Keyword(s):  
Aspergillus Nidulans ◽  
Blot Analysis ◽  
Regulatory Gene ◽  
Regulation Of Gene Expression ◽  
Strong Support ◽  
Cosmid Library ◽  
Loss Of Function ◽  
Structural Genes ◽  
Dna Rearrangements ◽  
Multiple Copies

The positively acting regulatory gene amdR of Aspergillus nidulans coordinately regulates the expression of four unlinked structural genes involved in acetamide (amdS), omega amino acid (gatA and gabA), and lactam (lamA) catabolism. By the use of DNA-mediated transformation of A. nidulans, the amdR regulatory gene was cloned from a genomic cosmid library. Southern blot analysis of DNA from various loss-of-function amdR mutants revealed the presence of four detectable DNA rearrangements, including a deletion, an insertion, and a translocation. No detectable DNA rearrangements were found in several constitutive amdRc mutants. Analysis of the fate of amdR-bearing plasmids in transformants showed that 10 to 20% of the transformation events were homologous integrations or gene conversions, and this phenomenon was exploited in developing a strategy by which amdRc and amdR- alleles can be readily cloned and analyzed. Examination of the transcription of amdR by Northern blot (RNA blot) analysis revealed the presence of two mRNAs (2.7 and 1.8 kilobases) which were constitutively synthesized at a very low level. In addition, amdR transcription did not appear to depend on the presence of a functional amdR product nor was it altered in amdRc mutants. The dosage effects of multiple copies of amdR in transformants were examined, and it was shown that such transformants exhibited stronger growth than did the wild type on acetamide and pyrrolidinone media, indicating increased expression of the amdS and lamA genes, respectively. These results were used to formulate a model for amdR-mediated regulation of gene expression in which the low constitutive level of amdR product sets the upper limits of basal and induced transcription of the structural genes. Multiple copies of 5' sequences from the amdS gene can result in reduced growth on substrates whose utilization is dependent on amdR-controlled genes. This has been attributed to titration of limiting amdR gene product. Strong support for this proposal was obtained by showing that multiple copies of the amdR gene can reverse this phenomenon (antititration).

scholarly journals Plasmid recombination intermediates generated in a Saccharomyces cerevisiae cell-free recombination system.

1985 ◽  
Vol 5 (9) ◽  
pp. 2361-2368 ◽  
Author(s):  
L S Symington ◽  
P Morrison ◽  
R Kolodner
Keyword(s):  
Electron Microscopy ◽  
Saccharomyces Cerevisiae ◽  
Electrophoretic Mobility ◽  
Electrophoretic Analysis ◽  
Individual Band ◽  
Agarose Gels ◽  
Cell Extracts ◽  
Recombination System ◽  
Plasmid Recombination

We have developed an assay utilizing Saccharomyces cerevisiae cell extracts to catalyze recombination in vitro between homologous plasmids containing different mutant alleles of the tet gene. Electrophoretic analysis of product DNA indicated that a number of novel DNA species were formed during the reaction. These species migrated through agarose gels as distinct bands with decreased electrophoretic mobility compared with the substrate DNA. The DNA from each individual band was purified and shown to be enriched 5- to 100-fold for tetracycline-resistant recombinants by using a transformation assay. The structure of the DNA molecules present in these bands was determined by electron microscopy. Recombination between circular substrates appeared to involve the formation and processing of figure-eight molecules, while recombination between circular and linear substrates involved the formation of molecules in which a circular monomer had a monomer-length linear tail attached at a region of homology.

scholarly journals GENETIC CONTROL OF CHROMOSOMAL AND PLASMID RECOMBINATION IN STAPHYLOCOCCUS AUREUS

Genetics ◽  
1974 ◽  
Vol 76 (4) ◽  
pp. 681-702
Author(s):  
L Wyman ◽  
R V Goering ◽  
R P Novick
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Genetic Control ◽  
Marked Reduction ◽  
Recombination System ◽  
Plasmid Recombination

ABSTRACT Recombination-deficient mutants of Staphylococcus aureus have been isolated and found to have properties similar to those of recombination-deficient Escherichia coli. In addition, one Rec- mutant was found to be defective in the restriction and modification of DNA. There is a marked reduction (∼ 104-fold) in recombination between penicillinase plasmids in the Rec- mutants suggesting that these elements do not encode an efficient recombination system. There is, however, a demonstrable residuum of interplasmid recombination; evidence is lacking on whether this residuum is a plasmid or host function. In the absence of the generalized host recombination system it has been possible to demonstrate that interplasmid recombination occurs during vegetative bacteriophage growth and is presumably mediated by a phage-determined recombination system.

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