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 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.

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