A Single Base-Pair Change (ATG → ATC) Nullifies the Activity of Cytosolic Fumarase in Saccharomyces cerevisiae

1995 ◽  
Vol 215 (2) ◽  
pp. 578-590 ◽  
Author(s):  
M. Wu ◽  
S.M. Wong ◽  
H.M. Tan ◽  
R. Ting
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Base Pair ◽  
Single Base ◽  
Single Base Pair ◽  
Single Base Pair Change

scholarly journals Point mutations implicate repeated sequences as essential elements of the CYC7 negative upstream site in Saccharomyces cerevisiae.

1985 ◽  
Vol 5 (11) ◽  
pp. 2951-2958 ◽  
Author(s):  
C F Wright ◽  
R S Zitomer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Sequences ◽  
Base Pair ◽  
Point Mutations ◽  
Regulatory Elements ◽  
Upstream Site ◽  
Single Base ◽  
Negative Element ◽  
Single Base Pair ◽  
Single Base Pair Change

The transcription of the CYC7 gene of Saccharomyces cerevisiae, encoding the iso-2-cytochrome c protein, is controlled by two upstream regulatory elements, a positive element and a negative element. The nature of the DNA sequences in the negative element were investigated in a two-part approach. The first involved the construction of a CYC7-galK fusion gene which placed the coding sequence of the Escherichia coli galactokinase gene under the regulation of the CYC7 upstream sequences. This fusion allowed the quantitation by galactokinase enzyme assays of the effects on gene expression of a variety of previously isolated deletion mutations within the negative site. The results suggested that the negative site contained three related sequences. This hypothesis was tested in the second part of these studies, the selection of point mutations within the region of the negative site which led to increased CYC7 expression. Point mutations were introduced by a technique which induced mutations within a localized region at high efficiency. All but one of the mutations involved more than a single base-pair change. The mutations followed the pattern that multiple base-pair changes occurred in one repeat or single base-pair changes occurred in two repeats, with the exception of one mutant, which had a single base-pair change in one repeat. This pattern of mutations and the base pairs that were altered strongly supported the hypothesis that the repeats are integral elements of the negative site.

Point mutations implicate repeated sequences as essential elements of the CYC7 negative upstream site in Saccharomyces cerevisiae

1985 ◽  
Vol 5 (11) ◽  
pp. 2951-2958
Author(s):  
C F Wright ◽  
R S Zitomer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Sequences ◽  
Base Pair ◽  
Point Mutations ◽  
Regulatory Elements ◽  
Upstream Site ◽  
Single Base ◽  
Negative Element ◽  
Single Base Pair ◽  
Single Base Pair Change

The transcription of the CYC7 gene of Saccharomyces cerevisiae, encoding the iso-2-cytochrome c protein, is controlled by two upstream regulatory elements, a positive element and a negative element. The nature of the DNA sequences in the negative element were investigated in a two-part approach. The first involved the construction of a CYC7-galK fusion gene which placed the coding sequence of the Escherichia coli galactokinase gene under the regulation of the CYC7 upstream sequences. This fusion allowed the quantitation by galactokinase enzyme assays of the effects on gene expression of a variety of previously isolated deletion mutations within the negative site. The results suggested that the negative site contained three related sequences. This hypothesis was tested in the second part of these studies, the selection of point mutations within the region of the negative site which led to increased CYC7 expression. Point mutations were introduced by a technique which induced mutations within a localized region at high efficiency. All but one of the mutations involved more than a single base-pair change. The mutations followed the pattern that multiple base-pair changes occurred in one repeat or single base-pair changes occurred in two repeats, with the exception of one mutant, which had a single base-pair change in one repeat. This pattern of mutations and the base pairs that were altered strongly supported the hypothesis that the repeats are integral elements of the negative site.

Host resistance to a fungal tomato pathogen lost by a single base-pair change in an avirulence gene

Nature ◽  
1994 ◽  
Vol 367 (6461) ◽  
pp. 384-386 ◽  
Author(s):  
Matthieu H. A. J. Joosten ◽  
Ton J. Cozijnsen ◽  
Pierre J. G. M. De Wit
Keyword(s):  
Host Resistance ◽  
Base Pair ◽  
Avirulence Gene ◽  
Single Base ◽  
Single Base Pair ◽  
Tomato Pathogen ◽  
Single Base Pair Change

scholarly journals A Single Base-Pair Change in 2009 H1N1 Hemagglutinin Increases Human Receptor Affinity and Leads to Efficient Airborne Viral Transmission in Ferrets

PLoS ONE ◽  
2011 ◽  
Vol 6 (3) ◽  
pp. e17616 ◽  
Author(s):  
Akila Jayaraman ◽  
Claudia Pappas ◽  
Rahul Raman ◽  
Jessica A. Belser ◽  
Karthik Viswanathan ◽  
...  
Keyword(s):  
Base Pair ◽  
Viral Transmission ◽  
Single Base ◽  
Receptor Affinity ◽  
2009 H1n1 ◽  
Single Base Pair ◽  
Single Base Pair Change ◽  
Human Receptor

The yeast rad18 mutator specifically increases G.C----T.A transversions without reducing correction of G-A or C-T mismatches to G.C pairs

1991 ◽  
Vol 11 (1) ◽  
pp. 218-225
Author(s):  
B A Kunz ◽  
X L Kang ◽  
L Kohalmi
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Synthesis ◽  
Dna Sequence ◽  
Base Pair ◽  
Mutation Frequency ◽  
Wild Type ◽  
Sequence Context ◽  
Single Base ◽  
Mutator Effect ◽  
Single Base Pair

Inactivation of the Saccharomyces cerevisiae RAD18 gene confers a mutator phenotype. To determine the specificity of this effect, a collection of 212 spontaneous SUP4-o mutants arising in a rad18 strain was characterized by DNA sequencing. Comparison of the resulting mutational spectrum with that for an isogenic wild-type (RAD18) strain revealed that the rad18 mutator specifically enhanced the frequency of single base pair substitutions. Further analysis indicated that an increase in the frequency of G.C----T.A transversions accounted for the elevated SUP4-o mutation frequency. Thus, rad18 is the first eucaryotic mutator found to generate only a particular base pair substitution. The majority of G.C pairs that were not mutated in the rad18 background were at sites where G.C----T.A events can be detected in SUP4-o, suggesting that DNA sequence context influences the rad18 mutator effect. Transformation of heteroduplex plasmid DNAs into the two strains demonstrated that the rad18 mutator did not reduce the efficiency of correcting G-A or C-T mismatches to G.C pairs or preferentially correct the mismatches to A.T pairs. We propose that the RAD18 gene product might contribute to the fidelity of DNA replication in S. cerevisiae by involvement in a process that serves to limit the formation of G-A and C-T mismatches at template guanine and cytosine sites during DNA synthesis.

scholarly journals A single base pair dominates over the novel identity of an Escherichia coli tyrosine tRNA in Saccharomyces cerevisiae.

1991 ◽  
Vol 11 (5) ◽  
pp. 2744-2751 ◽  
Author(s):  
V Trézéguet ◽  
H Edwards ◽  
P Schimmel
Keyword(s):  
Escherichia Coli ◽  
Saccharomyces Cerevisiae ◽  
Base Pair ◽  
Major Determinant ◽  
The Novel ◽  
Single Base ◽  
E Coli ◽  
Single Base Pair

The Escherichia coli su+3 tyrosine tRNA was shown recently to be a leucine-specific tRNA in Saccharomyces cerevisiae. This finding raises the possibility that some determinants for tRNA identity in E. coli may be different in S. cerevisiae. To investigate whether the fungal system is sensitive to the major determinant for alanine acceptance in E. coli, a single G3 . U70 base pair was introduced into the acceptor helix of the su+3 tyrosine tRNA. This substitution converts the identity of the E. coli suppressor in S. cerevisiae from leucine to alanine. Thus, as in E. coli, G3 . U70 is a strong determinant for alanine acceptance that can dominate over other features in a tRNA that might be recognized by alternative charging enzymes.

scholarly journals The yeast rad18 mutator specifically increases G.C----T.A transversions without reducing correction of G-A or C-T mismatches to G.C pairs.

1991 ◽  
Vol 11 (1) ◽  
pp. 218-225 ◽  
Author(s):  
B A Kunz ◽  
X L Kang ◽  
L Kohalmi
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Synthesis ◽  
Dna Sequence ◽  
Base Pair ◽  
Mutation Frequency ◽  
Wild Type ◽  
Sequence Context ◽  
Single Base ◽  
Mutator Effect ◽  
Single Base Pair

Inactivation of the Saccharomyces cerevisiae RAD18 gene confers a mutator phenotype. To determine the specificity of this effect, a collection of 212 spontaneous SUP4-o mutants arising in a rad18 strain was characterized by DNA sequencing. Comparison of the resulting mutational spectrum with that for an isogenic wild-type (RAD18) strain revealed that the rad18 mutator specifically enhanced the frequency of single base pair substitutions. Further analysis indicated that an increase in the frequency of G.C----T.A transversions accounted for the elevated SUP4-o mutation frequency. Thus, rad18 is the first eucaryotic mutator found to generate only a particular base pair substitution. The majority of G.C pairs that were not mutated in the rad18 background were at sites where G.C----T.A events can be detected in SUP4-o, suggesting that DNA sequence context influences the rad18 mutator effect. Transformation of heteroduplex plasmid DNAs into the two strains demonstrated that the rad18 mutator did not reduce the efficiency of correcting G-A or C-T mismatches to G.C pairs or preferentially correct the mismatches to A.T pairs. We propose that the RAD18 gene product might contribute to the fidelity of DNA replication in S. cerevisiae by involvement in a process that serves to limit the formation of G-A and C-T mismatches at template guanine and cytosine sites during DNA synthesis.

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