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.

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.

scholarly journals The phasmid as a tool for plasmid genetics: II. Isolation of point mutations that affect replication of a ColE1-related plasmid

1982 ◽  
Vol 40 (3) ◽  
pp. 233-247 ◽  
Author(s):  
Gianni Cesareni ◽  
Luisa Castagnoli ◽  
Sydney Brenner
Keyword(s):  
Copy Number ◽  
Point Mutations ◽  
Plasmid Replication ◽  
Single Base ◽  
Lambdoid Phage ◽  
Copy Number Plasmid ◽  
High Copy Number Plasmid ◽  
Single Base Pair ◽  
Related Plasmid ◽  
Single Base Pair Change

SUMMARYThe insertion of a high-copy-number plasmid into a lambdoid phage chromosome which lacks a functional repressor gene confers on the hybrid ‘phasmid’ the capacity to grow on an immune lysogen. This was found to be due to titration of repressor because of plasmid replication. We have exploited this property in order to isolate mutants that affect plasmid replication. These mutants have been mapped in a region that was previously characterized as necessary for plasmid replication and incompatibility properties. Some of the mutations could revert at frequencies characteristic of single-base-pair change mutations.

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

scholarly journals Saturation mutagenesis of twenty disease-associated regulatory elements at single base-pair resolution

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Martin Kircher ◽  
Chenling Xiong ◽  
Beth Martin ◽  
Max Schubach ◽  
Fumitaka Inoue ◽  
...  
Keyword(s):  
Base Pair ◽  
Regulatory Elements ◽  
Saturation Mutagenesis ◽  
Single Base ◽  
Single Base Pair

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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