scholarly journals Positive regulation of the beta-galactosidase gene from Kluyveromyces lactis is mediated by an upstream activation site that shows homology to the GAL upstream activation site of Saccharomyces cerevisiae.

1987 ◽  
Vol 7 (3) ◽  
pp. 991-997 ◽  
Author(s):  
M Ruzzi ◽  
K D Breunig ◽  
A G Ficca ◽  
C P Hollenberg
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Kluyveromyces Lactis ◽  
Consensus Sequence ◽  
Regulatory Gene ◽  
Lac Operon ◽  
Positive Regulation ◽  
Strong Homology ◽  
Gal Genes ◽  
Beta Galactosidase ◽  
Activation Site

In contrast to the Escherichia coli lac operon, the yeast beta-galactosidase gene is positively regulated. In the 5'-noncoding region of the Kluyveromyces lactis LAC4 gene, we mapped an upstream activation site (UAS) that is required for induction. This sequence, located between positions -435 and -326 from the start of translation, functions irrespective of its orientation and can confer lactose regulation to the heterologous CYC1 promoter. It is composed of at least two subsequences that must act in concert. One of these subsequences showed a strong homology to the UAS consensus sequence of the Saccharomyces cerevisiae GAL genes (E. Giniger, S. M. Varnum, and M. Ptashne, Cell 40:767-774, 1985). We propose that this region of homology located at about position -426 is a binding site for the product of the regulatory gene LAC9 which probably induces transcription of the LAC4 gene in a manner analogous to that of the GAL4 protein.

Positive regulation of the beta-galactosidase gene from Kluyveromyces lactis is mediated by an upstream activation site that shows homology to the GAL upstream activation site of Saccharomyces cerevisiae

1987 ◽  
Vol 7 (3) ◽  
pp. 991-997
Author(s):  
M Ruzzi ◽  
K D Breunig ◽  
A G Ficca ◽  
C P Hollenberg
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Kluyveromyces Lactis ◽  
Consensus Sequence ◽  
Regulatory Gene ◽  
Lac Operon ◽  
Positive Regulation ◽  
Strong Homology ◽  
Gal Genes ◽  
Beta Galactosidase ◽  
Activation Site

In contrast to the Escherichia coli lac operon, the yeast beta-galactosidase gene is positively regulated. In the 5'-noncoding region of the Kluyveromyces lactis LAC4 gene, we mapped an upstream activation site (UAS) that is required for induction. This sequence, located between positions -435 and -326 from the start of translation, functions irrespective of its orientation and can confer lactose regulation to the heterologous CYC1 promoter. It is composed of at least two subsequences that must act in concert. One of these subsequences showed a strong homology to the UAS consensus sequence of the Saccharomyces cerevisiae GAL genes (E. Giniger, S. M. Varnum, and M. Ptashne, Cell 40:767-774, 1985). We propose that this region of homology located at about position -426 is a binding site for the product of the regulatory gene LAC9 which probably induces transcription of the LAC4 gene in a manner analogous to that of the GAL4 protein.

Galactokinase encoded by GAL1 is a bifunctional protein required for induction of the GAL genes in Kluyveromyces lactis and is able to suppress the gal3 phenotype in Saccharomyces cerevisiae

1991 ◽  
Vol 11 (11) ◽  
pp. 5454-5461
Author(s):  
J Meyer ◽  
A Walker-Jonah ◽  
C P Hollenberg
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Kluyveromyces Lactis ◽  
Regulatory Function ◽  
Bifunctional Protein ◽  
Leloir Pathway ◽  
Gal Genes ◽  
Beta Galactosidase ◽  
Gal1 Gene ◽  
Galactokinase Activity ◽  
Negative Mutant

We have analyzed a GAL1 mutant (gal1-r strain) of the yeast Kluyveromyces lactis which lacks the induction of beta-galactosidase and the enzymes of the Leloir pathway in the presence of galactose. The data show that the K. lactis GAL1 gene product has, in addition to galactokinase activity, a function required for induction of the lactose system. This regulatory function is not dependent on galactokinase activity, as it is still present in a galactokinase-negative mutant (gal1-209). Complementation studies in Saccharomyces cervisiae show that K. lactis GAL1 and gal1-209, but not gal1-r, complement the gal3 mutation. We conclude that the regulatory function of GAL1 in K. lactis soon after induction is similar to the function of GAL3 in S. cerevisiae.

scholarly journals Galactokinase encoded by GAL1 is a bifunctional protein required for induction of the GAL genes in Kluyveromyces lactis and is able to suppress the gal3 phenotype in Saccharomyces cerevisiae.

1991 ◽  
Vol 11 (11) ◽  
pp. 5454-5461 ◽  
Author(s):  
J Meyer ◽  
A Walker-Jonah ◽  
C P Hollenberg
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Kluyveromyces Lactis ◽  
Regulatory Function ◽  
Bifunctional Protein ◽  
Leloir Pathway ◽  
Gal Genes ◽  
Beta Galactosidase ◽  
Gal1 Gene ◽  
Galactokinase Activity ◽  
Negative Mutant

We have analyzed a GAL1 mutant (gal1-r strain) of the yeast Kluyveromyces lactis which lacks the induction of beta-galactosidase and the enzymes of the Leloir pathway in the presence of galactose. The data show that the K. lactis GAL1 gene product has, in addition to galactokinase activity, a function required for induction of the lactose system. This regulatory function is not dependent on galactokinase activity, as it is still present in a galactokinase-negative mutant (gal1-209). Complementation studies in Saccharomyces cervisiae show that K. lactis GAL1 and gal1-209, but not gal1-r, complement the gal3 mutation. We conclude that the regulatory function of GAL1 in K. lactis soon after induction is similar to the function of GAL3 in S. cerevisiae.

Evolution of moonlighting proteins: insight from yeasts

2014 ◽  
Vol 42 (6) ◽  
pp. 1715-1719 ◽  
Author(s):  
Carlos Gancedo ◽  
Carmen-Lisset Flores ◽  
Juana M. Gancedo
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Present Article ◽  
Catabolite Repression ◽  
Kluyveromyces Lactis ◽  
Approaches To Studying ◽  
Moonlighting Proteins ◽  
Experimental Approaches ◽  
Gal Genes

The present article addresses the possibilities offered by yeasts to study the problem of the evolution of moonlighting proteins. It focuses on data available on hexokinase from Saccharomyces cerevisiae that moonlights in catabolite repression and on galactokinase from Kluyveromyces lactis that moonlights controlling the induction of the GAL genes. Possible experimental approaches to studying the evolution of moonlighting hexose kinases are suggested.

scholarly journals Characterization of a positive regulatory gene, LAC9, that controls induction of the lactose-galactose regulon of Kluyveromyces lactis: structural and functional relationships to GAL4 of Saccharomyces cerevisiae.

1987 ◽  
Vol 7 (3) ◽  
pp. 1111-1121 ◽  
Author(s):  
L V Wray ◽  
M M Witte ◽  
R C Dickson ◽  
M I Riley
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Metal Binding ◽  
Glucose Repression ◽  
Kluyveromyces Lactis ◽  
Regulatory Gene ◽  
Regulatory Protein ◽  
Constitutive Expression ◽  
Functional Relationships ◽  
Functional Implications

Lactose or galactose induces the expression of the lactose-galactose regulon in Kluyveromyces lactis. We show here that the regulon is not induced in strains defective in LAC9. We demonstrate that this gene codes for a regulatory protein that acts in a positive manner to induce transcription. The LAC9 gene was isolated by complementation of a lac9 defective strain. DNA sequence analysis of the gene gave a deduced protein of 865 amino acids. Comparison of this sequence with that of the GAL4 protein of Saccharomyces cerevisiae revealed three regions of homology. One region of about 90 amino acid occurs at the amino terminus, which is known to mediate binding of GAL4 protein to upstream activator sequences. We speculate that a portion of this region, adjacent to the "metal-binding finger," specifies DNA binding. We discuss possible functions of the two other regions of homology. The functional implications of these structural similarities were examined. When LAC9 was introduced into a gal4 defective strain of S. cerevisiae it complemented the mutation and activated the galactose-melibiose regulon. However, LAC9 did not simply mimic GAL4. Unlike normal S. cerevisiae carrying GAL4, the strain carrying LAC9 gave constitutive expression of GAL1 and MEL1, two genes in the regulon. The strain did show glucose repression of the regulon, but repression was less severe with LAC9 than with GAL4. We discuss the implications of these results and how they may facilitate our understanding of the LAC9 and GAL4 regulatory proteins.

scholarly journals Absence of step changes in activity of certain enzymes during the cell cycle of budding and fission yeasts in synchronous cultures

1983 ◽  
Vol 61 (1) ◽  
pp. 339-349
Author(s):  
J. Creanor ◽  
S.G. Elliott ◽  
Y.C. Bisset ◽  
J.M. Mitchison
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Acid Phosphatase ◽  
Kluyveromyces Lactis ◽  
The Other ◽  
Linear Pattern ◽  
Synchronous Cultures ◽  
Asynchronous Control ◽  
Alpha Glucosidase ◽  
Beta Galactosidase

Synchronous cultures prepared by selection from an elutriating rotor were used to measure activity changes during the cell cycle of the following enzymes: acid phosphatase in Schizosaccharomyces pombe and Saccharomyces cerevisiae, alpha-glucosidase in S. cerevisiae and beta-galactosidase in Kluyveromyces lactis. There was no sign of step rises in activity in acid phosphatase but there were indications in S. cerevisiae of the linear pattern with rate doublings once per cycle that had been found previously in S. pombe. There was also no sign of step rises in the other two enzymes, in contrast to earlier results using different techniques. Asynchronous control cultures showed little or no perturbations after the first hour.

scholarly journals The signal for glucose repression of the lactose-galactose regulon is amplified through subtle modulation of transcription of the Kluyveromyces lactis Kl-GAL4 activator gene.

1992 ◽  
Vol 12 (5) ◽  
pp. 1924-1931 ◽  
Author(s):  
N Kuzhandaivelu ◽  
W K Jones ◽  
A K Martin ◽  
R C Dickson
Keyword(s):  
Glucose Repression ◽  
Rotational Symmetry ◽  
Kluyveromyces Lactis ◽  
Regulatory Gene ◽  
Regulatory Protein ◽  
Genetic Regulation ◽  
Structural Genes ◽  
Important Principle ◽  
Biological Phenomena ◽  
Beta Galactosidase

Induction of the lactose-galactose regulon is strongly repressed by glucose in some but not all strains of Kluyveromyces lactis. We show here that in strongly repressed strains, two to three times less Kl-GAL4 mRNA is synthesized and that expression of structural genes in the regulon such as LAC4, the structural gene for beta-galactosidase, is down regulated 40-fold or more. Comparative analysis of strains having a strong or weak repression phenotype revealed a two-base difference in the promoter of the Kl-GAL4 (also called LAC9) positive regulatory gene. This two-base difference is responsible for the strong versus the weak repression phenotype. The two base changes are symmetrically located in a DNA sequence having partial twofold rotational symmetry (14 of 21 bases). We hypothesize that this region functions as a sensitive regulatory switch, an upstream repressor sequence (URS). According to our model, the presence of glucose in the culture medium signals, by an unidentified pathway, a repressor protein to bind the URS. Binding reduces transcription of the Kl-GAL4 gene so that the concentration of the Kl-GAL4 protein falls below the level needed for induction of LAC4 and other genes in the regulon. For strains showing weak glucose repression, we hypothesize that the two base changes in the URS reduce repressor binding so that the regulon is not repressed. Our results illustrate an important principle of genetic regulation: a small (2- to 3-fold) change in the concentration of a regulatory protein can produce a large (40-fold or greater) change in expression of structural genes. This mechanism of signal amplification could play a role in many biological phenomena that require regulated transcription.

Characterization of a positive regulatory gene, LAC9, that controls induction of the lactose-galactose regulon of Kluyveromyces lactis: structural and functional relationships to GAL4 of Saccharomyces cerevisiae

1987 ◽  
Vol 7 (3) ◽  
pp. 1111-1121
Author(s):  
L V Wray ◽  
M M Witte ◽  
R C Dickson ◽  
M I Riley
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Metal Binding ◽  
Glucose Repression ◽  
Kluyveromyces Lactis ◽  
Regulatory Gene ◽  
Regulatory Protein ◽  
Constitutive Expression ◽  
Functional Relationships ◽  
Functional Implications

Lactose or galactose induces the expression of the lactose-galactose regulon in Kluyveromyces lactis. We show here that the regulon is not induced in strains defective in LAC9. We demonstrate that this gene codes for a regulatory protein that acts in a positive manner to induce transcription. The LAC9 gene was isolated by complementation of a lac9 defective strain. DNA sequence analysis of the gene gave a deduced protein of 865 amino acids. Comparison of this sequence with that of the GAL4 protein of Saccharomyces cerevisiae revealed three regions of homology. One region of about 90 amino acid occurs at the amino terminus, which is known to mediate binding of GAL4 protein to upstream activator sequences. We speculate that a portion of this region, adjacent to the "metal-binding finger," specifies DNA binding. We discuss possible functions of the two other regions of homology. The functional implications of these structural similarities were examined. When LAC9 was introduced into a gal4 defective strain of S. cerevisiae it complemented the mutation and activated the galactose-melibiose regulon. However, LAC9 did not simply mimic GAL4. Unlike normal S. cerevisiae carrying GAL4, the strain carrying LAC9 gave constitutive expression of GAL1 and MEL1, two genes in the regulon. The strain did show glucose repression of the regulon, but repression was less severe with LAC9 than with GAL4. We discuss the implications of these results and how they may facilitate our understanding of the LAC9 and GAL4 regulatory proteins.

scholarly journals GAL4 of Saccharomyces cerevisiae activates the lactose-galactose regulon of Kluyveromyces lactis and creates a new phenotype: glucose repression of the regulon.

1987 ◽  
Vol 7 (2) ◽  
pp. 780-786 ◽  
Author(s):  
M I Riley ◽  
J E Hopper ◽  
S A Johnston ◽  
R C Dickson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Type Strain ◽  
Wild Type Strain ◽  
Glucose Repression ◽  
Kluyveromyces Lactis ◽  
Galactosidase Activity ◽  
Wild Type ◽  
Fold Induction ◽  
Beta Galactosidase ◽  
Galactokinase Activity

A Kluyveromyces lactis mutant defective in lac9 cannot induce beta-galactosidase or galactokinase activity and is unable to grow on lactose or galactose. When this strain was transformed with the GAL4 positive regulatory gene of Saccharomyces cerevisiae it was able to grow on lactose or galactose as the sole carbon source. Transformants bearing GAL4 exhibited a 4.5-h generation time on galactose or lactose, versus 24 h for the nontransformed lac9 strain. A K. lactis lac9 strain bearing two integrated copies of GAL4 showed 3.5-fold induction of beta-galactosidase activity and 1.8-fold induction of galactokinase activity compared with 15.6-fold and 4.4-fold induction, respectively, for the LAC9 wild-type strain. In transformants bearing 10 integrated copies of GAL4, the induced level of beta-galactosidase was nearly as high as in the LAC9 wild-type strain. In addition to restoring lactose and galactose gene expression, GAL4 in K. lactis lac9 mutant cells conferred a new phenotype, severe glucose repression of lactose and galactose-inducible enzymes. Glucose repressed beta-galactosidase activity 35- to 74-fold and galactokinase activity 14- to 31-fold in GAL4 transformants, compared with the 2-fold glucose repression exhibited in the LAC9 wild-type strain. The S. cerevisiae MEL1 gene was repressed fourfold by glucose in LAC9 cells. In contrast, the MEL1 gene in a GAL4 lac9 strain was repressed 20-fold by glucose. These results indicate that the GAL4 and LAC9 proteins activate transcription in a similar manner. However, either the LAC9 or GAL4 gene or a product of these genes responds differently to glucose in K. lactis.

The signal for glucose repression of the lactose-galactose regulon is amplified through subtle modulation of transcription of the Kluyveromyces lactis Kl-GAL4 activator gene

1992 ◽  
Vol 12 (5) ◽  
pp. 1924-1931
Author(s):  
N Kuzhandaivelu ◽  
W K Jones ◽  
A K Martin ◽  
R C Dickson
Keyword(s):  
Glucose Repression ◽  
Rotational Symmetry ◽  
Kluyveromyces Lactis ◽  
Regulatory Gene ◽  
Regulatory Protein ◽  
Genetic Regulation ◽  
Structural Genes ◽  
Important Principle ◽  
Biological Phenomena ◽  
Beta Galactosidase

Induction of the lactose-galactose regulon is strongly repressed by glucose in some but not all strains of Kluyveromyces lactis. We show here that in strongly repressed strains, two to three times less Kl-GAL4 mRNA is synthesized and that expression of structural genes in the regulon such as LAC4, the structural gene for beta-galactosidase, is down regulated 40-fold or more. Comparative analysis of strains having a strong or weak repression phenotype revealed a two-base difference in the promoter of the Kl-GAL4 (also called LAC9) positive regulatory gene. This two-base difference is responsible for the strong versus the weak repression phenotype. The two base changes are symmetrically located in a DNA sequence having partial twofold rotational symmetry (14 of 21 bases). We hypothesize that this region functions as a sensitive regulatory switch, an upstream repressor sequence (URS). According to our model, the presence of glucose in the culture medium signals, by an unidentified pathway, a repressor protein to bind the URS. Binding reduces transcription of the Kl-GAL4 gene so that the concentration of the Kl-GAL4 protein falls below the level needed for induction of LAC4 and other genes in the regulon. For strains showing weak glucose repression, we hypothesize that the two base changes in the URS reduce repressor binding so that the regulon is not repressed. Our results illustrate an important principle of genetic regulation: a small (2- to 3-fold) change in the concentration of a regulatory protein can produce a large (40-fold or greater) change in expression of structural genes. This mechanism of signal amplification could play a role in many biological phenomena that require regulated transcription.

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