Nuclear Demethylation and C-24 Alkylation During Ergosterol Biosynthesis in Saccharomyces cerevisiae

1975 ◽  
Vol 53 (8) ◽  
pp. 881-889 ◽  
Author(s):  
M. Fryberg ◽  
L. Avruch ◽  
A. C. Oehlschlager ◽  
A. M. Unrau
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ergosterol Biosynthesis ◽  
Aerobic Growth ◽  
Equal Importance ◽  
Major Route ◽  
Commercial Yeast

The role of 4,4-dimethylzymosterol (3), 4,4-dimethylfecosterol (4) and 31-norlanosterol (5) in the biosynthesis of ergosterol in Saccharomyces cerevisiae has been investigated. The synthesis of 4 and 5 coupled with the availability of 3 facilitated a search for these sterols in commercial yeast sterol concentrates, fresh laboratory grown yeast and fresh brewery grown yeast. Sterol 4 was not detected in any of these mixtures whereas 5 was found in the first and last and 3 was present in all three sources investigated. Investigation of incorporation of [2-3H]lanosterol into 3, 4 and 5 revealed significant incorporation into 3 but neither 4 nor 5. This observation suggests the principle pathway for ergosterol biosynthesis initially involved 1 → 3 → 7.Incubation of a mixture of [2,4-3H]zymosterol and [26,27-14C]lanosterol with S. cerevisiae revealed that during the initial phases of aerobic growth the major route from 7 to ergosterol involves zymosterol (11) but as 11 accumulates 4α-methyl-24-methylenezymosterol (8) assumes equal importance.

scholarly journals The intermediary role of a steroid 8,14-dien-3β-ol system in ergosterol biosynthesis

1969 ◽  
Vol 115 (2) ◽  
pp. 135-137 ◽  
Author(s):  
M Akhtar ◽  
W. A. Brooks ◽  
I. A. Watkinson
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ergosterol Biosynthesis ◽  
Methyl Group ◽  
Diene System ◽  
Intermediary Role

1. A mechanism for the removal of the 14α-methyl group in ergosterol biosynthesis that involves the intermediacy of an 8,14-diene system is outlined. 2. In accordance with the requirements of this scheme, it is shown that 5α-ergosta-8,14-dien-3β-ol is converted into ergosterol by Saccharomyces cerevisiae.

scholarly journals ROX1 encodes a heme-induced repression factor regulating ANB1 and CYC7 of Saccharomyces cerevisiae.

1988 ◽  
Vol 8 (11) ◽  
pp. 4651-4658 ◽  
Author(s):  
C V Lowry ◽  
R S Zitomer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Constitutive Expression ◽  
Null Mutant ◽  
Aerobic Growth ◽  
The Family ◽  
Negative Effect ◽  
Induced Genes ◽  
Cloned Gene ◽  
Null Strain

The ROX1 gene encodes a product implicated in the regulation of heme-repressed and heme-induced genes in Saccharomyces cerevisiae. The gene has been cloned and shown to code for a 1.4-kilobase transcript. The cloned gene was used to construct a null mutant to determine the role of ROX1 in regulating the expression of several heme-regulated genes. Constitutive expression of ANB1 (a heme-repressed gene) was observed in the null strain, indicating that ROX1 codes for a repressor or a facilitator of repression. Enhancement of expression of CYC7 in the null strain indicated that the ROX1 factor is required for repression of CYC7 to its normal low level of expression, consistent with evidence that CYC7 has a hybrid heme-induced, heme-repressed regulatory mechanism. The null mutation had only a slight negative effect on expression of the heme-induced genes CYC1 and tr-1 (a heme-induced homolog of ANB1), suggesting that the ROX1 factor is not directly involved in their regulation despite the existence of an unusual rox1 mutation (rox1-a1) causing constitutive expression of this group. The respiratory competence of the null mutant indicates that ROX1 is not a respiratory factor. ROX1 expression was found to be induced by heme, indicating that the heme repression of ANB1 and its family is the result of a cascade in which heme induces a repression factor which keeps the family of heme-repressed genes inactive during aerobic growth. The rox1-a1 allele had earlier been shown to cause constitutive expression of the family of heme-induced respiratory genes. This allele was found to cause constitutive expression of the ROX1 transcript itself, indicating that ROX1 is in the major heme-induced regulon.

scholarly journals Combinatorial Repression of the Hypoxic Genes of Saccharomyces cerevisiae by DNA Binding Proteins Rox1 and Mot3

2005 ◽  
Vol 4 (4) ◽  
pp. 649-660 ◽  
Author(s):  
Lee G. Klinkenberg ◽  
Thomas A. Mennella ◽  
Katharina Luetkenhaus ◽  
Richard S. Zitomer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Binding ◽  
Chromatin Immunoprecipitation ◽  
Binding Sites ◽  
Binding Protein ◽  
Dna Binding Protein ◽  
Aerobic Growth ◽  
Repression Complex ◽  
Combinatorial Interactions

ABSTRACT The hypoxic genes of Saccharomyces cerevisiae are transcriptionally repressed during aerobic growth through recruitment of the Ssn6/Tup1 general repression complex by the DNA binding protein Rox1. A second DNA binding protein Mot3 enhances repression of some hypoxic genes. Previous studies characterized the role of Mot3 at the hypoxic ANB1 gene as promoting synergy among one Mot3 site and two Rox1 sites comprising operator A of that gene. Here we studied the role of Mot3 in enhancing repression by Rox1 at another hypoxic gene, HEM13, which is less strongly regulated than ANB1 and has a very different arrangement of Rox1 and Mot3 binding sites. By assessing the effects of deleting Rox1 and Mot3 sites individually and in combination, we found that the major repression of HEM13 occurred through three Mot3 sites closely spaced with a single Rox1 site. While the Mot3 sites functioned additively, they enhanced repression by the single Rox1 site, and the presence of Rox1 enhanced the additive effects of the Mot3 sites. In addition, using a Rox1-Ssn6 fusion protein, we demonstrated that Mot3 enhances Rox1 repression through helping recruit the Ssn6/Tup1 complex. Chromatin immunoprecipitation assays indicated that Rox1 stabilized Mot3 binding to DNA. Integrating these results, we were able to devise a set of rules that govern the combinatorial interactions between Rox1 and Mot3 to achieve differential repression.

ROX1 encodes a heme-induced repression factor regulating ANB1 and CYC7 of Saccharomyces cerevisiae

1988 ◽  
Vol 8 (11) ◽  
pp. 4651-4658
Author(s):  
C V Lowry ◽  
R S Zitomer
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Constitutive Expression ◽  
Null Mutant ◽  
Aerobic Growth ◽  
The Family ◽  
Negative Effect ◽  
Induced Genes ◽  
Cloned Gene ◽  
Null Strain

The ROX1 gene encodes a product implicated in the regulation of heme-repressed and heme-induced genes in Saccharomyces cerevisiae. The gene has been cloned and shown to code for a 1.4-kilobase transcript. The cloned gene was used to construct a null mutant to determine the role of ROX1 in regulating the expression of several heme-regulated genes. Constitutive expression of ANB1 (a heme-repressed gene) was observed in the null strain, indicating that ROX1 codes for a repressor or a facilitator of repression. Enhancement of expression of CYC7 in the null strain indicated that the ROX1 factor is required for repression of CYC7 to its normal low level of expression, consistent with evidence that CYC7 has a hybrid heme-induced, heme-repressed regulatory mechanism. The null mutation had only a slight negative effect on expression of the heme-induced genes CYC1 and tr-1 (a heme-induced homolog of ANB1), suggesting that the ROX1 factor is not directly involved in their regulation despite the existence of an unusual rox1 mutation (rox1-a1) causing constitutive expression of this group. The respiratory competence of the null mutant indicates that ROX1 is not a respiratory factor. ROX1 expression was found to be induced by heme, indicating that the heme repression of ANB1 and its family is the result of a cascade in which heme induces a repression factor which keeps the family of heme-repressed genes inactive during aerobic growth. The rox1-a1 allele had earlier been shown to cause constitutive expression of the family of heme-induced respiratory genes. This allele was found to cause constitutive expression of the ROX1 transcript itself, indicating that ROX1 is in the major heme-induced regulon.

Protective role of l ‐threonine against cadmium toxicity in Saccharomyces cerevisiae

2021 ◽  
Author(s):  
Linru Huang ◽  
Zhijia Fang ◽  
Jian Gao ◽  
Jingwen Wang ◽  
Yongbin Li ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cadmium Toxicity ◽  
Protective Role

scholarly journals Suppressor Analysis of the Saccharomyces cerevisiae Gene REC104 Reveals a Genetic Interaction With REC102

Genetics ◽  
1999 ◽  
Vol 151 (4) ◽  
pp. 1261-1272 ◽  
Author(s):  
Laura Salem ◽  
Natalie Walter ◽  
Robert Malone
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Meiotic Recombination ◽  
Null Allele ◽  
Genetic Interaction ◽  
In Vitro Mutagenesis ◽  
Conditional Mutations ◽  
Suppressor Analysis

Abstract REC104 is a gene required for the initiation of meiotic recombination in Saccharomyces cerevisiae. To better understand the role of REC104 in meiosis, we used an in vitro mutagenesis technique to create a set of temperature-conditional mutations in REC104 and used one ts allele (rec104-8) in a screen for highcopy suppressors. An increased dosage of the early exchange gene REC102 was found to suppress the conditional recombinational reduction in rec104-8 as well as in several other conditional rec104 alleles. However, no suppression was observed for a null allele of REC104, indicating that the suppression by REC102 is not “bypass” suppression. Overexpression of the early meiotic genes REC114, RAD50, HOP1, and RED1 fails to suppress any of the rec104 conditional alleles, indicating that the suppression might be specific to REC102.

Role of Oxidative Phosphorylation in Histatin 5-Induced Cell Death in Saccharomyces cerevisiae

2004 ◽  
Vol 26 (23) ◽  
pp. 1781-1785 ◽  
Author(s):  
Kris De Smet ◽  
Rieka Reekmans ◽  
Roland Contreras
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Death ◽  
Oxidative Phosphorylation ◽  
Histatin 5
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