scholarly journals Two temperature-sensitive mutants of Saccharomyces cerevisiae with altered expression of mating-type functions.

1983 ◽  
Vol 96 (6) ◽  
pp. 1592-1600 ◽  
Author(s):  
T R Manney ◽  
P Jackson ◽  
J Meade
Keyword(s):  
Saccharomyces Cerevisiae ◽  
The Other ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Altered Expression ◽  
Temperature Sensitive Mutants ◽  
Sporulation Efficiency ◽  
Mating Efficiency ◽  
Sensitive Allele ◽  
Two Temperature

Two mutants of Saccharomyces cerevisiae have been isolated from normal haploid MAT alpha strains and characterized as having temperature-sensitive, pleiotropic phenotypes for functions associated with mating. At the permissive temperature, 23 degrees C, they were found to behave as normal MAT alpha haploids with respect to mating efficiency, sporulation in diploids formed with MAT a strains, secretion of alpha-factor, and failure to secrete the MATa-specific products, a-factor and Barrier. At higher temperatures they were found to decline in mating and sporulation efficiency and to express the a-specific functions. Genetic analysis established that one of these mutants, PE34, carries a temperature-sensitive allele of the MAT alpha 2 gene and that the other, PD7, carries a temperature-sensitive allele of the TUP1 gene.

TEMPERATURE-SENSITIVE MUTANTS OF ANACYSTIS NIDULANS

Genetics ◽  
1972 ◽  
Vol 71 (3) ◽  
pp. 465-467
Author(s):  
Anthony R Kaney ◽  
Mary P Dolack
Keyword(s):  
Anacystis Nidulans ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Temperature Sensitive Mutants ◽  
Two Temperature

Abstract One hundred forty-two temperature-sensitive mutants of Anacystis nidulans were isolated. None are supplementable at the non-permissive temperature, suggesting the possibility that mutations resulting in auxotrophy are lethal in this organism.

scholarly journals Rapid decrease in thymidine kinase activity of mouse cell temperature-sensitive mutants at a non-permissive temperature

1981 ◽  
Vol 198 (2) ◽  
pp. 347-352 ◽  
Author(s):  
M Hyodo ◽  
K Suzuki
Keyword(s):  
Thymidine Kinase ◽  
Kinase Activity ◽  
Mouse Cell ◽  
Rapid Decrease ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Thymidine Kinase Activity ◽  
Cell Temperature ◽  
Temperature Sensitive Mutants ◽  
Two Temperature

A rapid decrease in the incorporation of [3H]thymidine into DNA at a non-permissive temperature was observed in two temperature-sensitive mutants that were isolated from mouse FM3A cells. This change was not due to a decrease in the rate of DNA replication, but was closely associated with a decrease in thymidine kinase activity of these cells. Experiments to test thermolability of thymidine kinase in extracts showed that there are two components of the thymidine kinase, but there was no alteration in the sensitivity of the enzyme to high temperature. Also, the decrease in enzyme activity in the temperature-sensitive mutants at the non-permissive temperature occurred much faster than expected from the half-life of the enzyme in wild-type cells, which was measured in the presence of cycloheximide. These results suggested that the enzyme was somehow rapidly inactivated, or degraded, in the cells at the non-permissive temperature.

scholarly journals Characterization of Schizosaccharomyces pombe mcm7+ and cdc23+ (MCM10) and Interactions With Replication Checkpoints

Genetics ◽  
2001 ◽  
Vol 159 (2) ◽  
pp. 471-486 ◽  
Author(s):  
Debbie T Liang ◽  
Susan L Forsburg
Keyword(s):  
Fission Yeast ◽  
S Phase ◽  
The Other ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
2C Dna Content ◽  
Mcm Proteins ◽  
Sensitive Allele ◽  
Synthetically Lethal ◽  
Yeast Homolog

Abstract MCM proteins are required for the proper regulation of DNA replication. We cloned fission yeast mcm7+ and showed it is essential for viability; spores lacking mcm7+ begin S phase later than wild-type cells and arrest with an apparent 2C DNA content. We isolated a novel temperature-sensitive allele, mcm7-98, and also characterized two temperature-sensitive alleles of the fission yeast homolog of MCM10, cdc23+. mcm7-98 and both cdc23ts alleles arrest with damaged chromosomes and an S phase delay. We find that mcm7-98 is synthetically lethal with the other mcmts mutants but does not interact genetically with either cdc23ts allele. However, cdc23-M36 interacts with mcm4ts. Unlike other mcm mutants or cdc23, mcm7-98 is synthetically lethal with checkpoint mutants Δcds1, Δchk1, or Δrad3, suggesting chromosomal defects even at permissive temperature. Mcm7p is a nuclear protein throughout the cell cycle, and its localization is dependent on the other MCM proteins. Our data suggest that the Mcm3p-Mcm5p dimer interacts with the Mcm4p-Mcm6p-Mcm7p core complex through Mcm7p.

New temperature-sensitive mutants of Saccharomyces cerevisiae affecting DNA replication

1982 ◽  
Vol 187 (1) ◽  
pp. 42-46 ◽  
Author(s):  
Lawrence B. Dumas ◽  
Joan P. Lussky ◽  
Elizabeth J. McFarland ◽  
Janis Shampay
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Replication ◽  
Temperature Sensitive ◽  
Temperature Sensitive Mutants

The Mitochondrial Nucleoid Protein, Mgm101p, of Saccharomyces cerevisiae Is Involved in the Maintenance of ρ+ and ori/rep-Devoid Petite Genomes but Is Not Required for Hypersuppressive ρ− mtDNA

Genetics ◽  
2002 ◽  
Vol 160 (4) ◽  
pp. 1389-1400
Author(s):  
Xiao Ming Zuo ◽  
G Desmond Clark-Walker ◽  
Xin Jie Chen
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Mitochondrial Rna ◽  
Mtdna Copy Number ◽  
Mitochondrial Rna Polymerase ◽  
Mitochondrial Nucleoids ◽  
Mtdna Replication ◽  
Sensitive Allele ◽  
Discriminatory Effect

Abstract The Saccharomyces cerevisiae MGM101 gene encodes a DNA-binding protein targeted to mitochondrial nucleoids. MGM101 is essential for maintenance of a functional ρ+ genome because meiotic segregants, with a disrupted mgm101 allele, cannot undergo more than 10 divisions on glycerol medium. Quantitative analysis of mtDNA copy number in a ρ+ strain carrying a temperature-sensitive allele, mgm101-1, revealed that the amount of mtDNA is halved each cell division upon a shift to the restrictive temperature. These data suggest that mtDNA replication is rapidly blocked in cells lacking MGM101. However, a small proportion of meiotic segregants, disrupted in MGM101, have ρ− genomes that are stably maintained. Interestingly, all surviving ρ− mtDNAs contain an ori/rep sequence. Disruption of MGM101 in hypersuppressive (HS) strains does not have a significant effect on the propagation of HS ρ− mtDNA. However, in petites lacking an ori/rep, disruption of MGM101 leads to either a complete loss or a dramatically decreased stability of mtDNA. This discriminatory effect of MGM101 suggests that replication of ρ+ and ori/rep-devoid ρ− mtDNAs is carried out by the same process. By contrast, the persistence of ori/rep-containing mtDNA in HS petites lacking MGM101 identifies a distinct replication pathway. The alternative mtDNA replication mechanism provided by ori/rep is independent of mitochondrial RNA polymerase encoded by RPO41 as a HS ρ− genome is stably maintained in a mgm101, rpo41 double mutant.

DBF8, an essential gene required for efficient chromosome segregation in Saccharomyces cerevisiae

1994 ◽  
Vol 14 (9) ◽  
pp. 6350-6360
Author(s):  
F Houman ◽  
C Holm
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Chromosome Segregation ◽  
Mutational Analysis ◽  
Essential Gene ◽  
Chromosome Loss ◽  
Temperature Sensitive ◽  
Restrictive Temperature ◽  
Permissive Temperature ◽  
Nonsense Mutations ◽  
Carboxy Terminal

To investigate chromosome segregation in Saccharomyces cerevisiae, we examined a collection of temperature-sensitive mutants that arrest as large-budded cells at restrictive temperatures (L. H. Johnston and A. P. Thomas, Mol. Gen. Genet. 186:439-444, 1982). We characterized dbf8, a mutation that causes cells to arrest with a 2c DNA content and a short spindle. DBF8 maps to chromosome IX near the centromere, and it encodes a 36-kDa protein that is essential for viability at all temperatures. Mutational analysis reveals that three dbf8 alleles are nonsense mutations affecting the carboxy-terminal third of the encoded protein. Since all of these mutations confer temperature sensitivity, it appears that the carboxyl-terminal third of the protein is essential only at a restrictive temperature. In support of this conclusion, an insertion of URA3 at the same position also confers a temperature-sensitive phenotype. Although they show no evidence of DNA damage, dbf8 mutants exhibit increased rates of chromosome loss and nondisjunction even at a permissive temperature. Taken together, our data suggest that Dbf8p plays an essential role in chromosome segregation.

scholarly journals Dispersed Mutations in Histone H3 That Affect Transcriptional Repression and Chromatin Structure of the CHA1 Promoter in Saccharomyces cerevisiae

2008 ◽  
Vol 7 (10) ◽  
pp. 1649-1660 ◽  
Author(s):  
Qiye He ◽  
Cailin Yu ◽  
Randall H. Morse
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Chromatin Structure ◽  
Transcriptional Repression ◽  
Histone H3 ◽  
Temperature Sensitive ◽  
Active Chromatin ◽  
Temperature Sensitive Mutants ◽  
Nucleosome Structure ◽  
Lysine Residues ◽  
Chromatin Configuration

ABSTRACT The histone H3 amino terminus, but not that of H4, is required to prevent the constitutively bound activator Cha4 from remodeling chromatin and activating transcription at the CHA1 gene in Saccharomyces cerevisiae. Here we show that neither the modifiable lysine residues nor any specific region of the H3 tail is required for repression of CHA1. We then screened for histone H3 mutations that cause derepression of the uninduced CHA1 promoter and identified six mutants, three of which are also temperature-sensitive mutants and four of which exhibit a sin − phenotype. Histone mutant levels were similar to that of wild-type H3, and the mutations did not cause gross alterations in nucleosome structure. One specific and strongly derepressing mutation, H3 A111G, was examined in depth and found to cause a constitutively active chromatin configuration at the uninduced CHA1 promoter as well as at the ADH2 promoter. Transcriptional derepression and altered chromatin structure of the CHA1 promoter depend on the activator Cha4. These results indicate that modest perturbations in distinct regions of the nucleosome can substantially affect the repressive function of chromatin, allowing activation in the absence of a normal inducing signal (at CHA1) or of Swi/Snf (resulting in a sin − phenotype).

Identification of the defects in the hemagglutinin gene of two temperature-sensitive mutants of A/WSN/33 influenza virus

Virology ◽  
1986 ◽  
Vol 154 (2) ◽  
pp. 279-285 ◽  
Author(s):  
Setsuko Nakajima ◽  
Donald J. Brown ◽  
Masahiro Ueda ◽  
Katsuhisa Nakajima ◽  
Akira Sugiura ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Temperature Sensitive ◽  
Temperature Sensitive Mutants ◽  
Hemagglutinin Gene ◽  
Two Temperature

scholarly journals Mistranslating tRNA identifies a deleterious S213P mutation in the Saccharomyces cerevisiae eco1-1 allele

2020 ◽  
Vol 98 (5) ◽  
pp. 624-630 ◽  
Author(s):  
Yanrui Zhu ◽  
Matthew D. Berg ◽  
Phoebe Yang ◽  
Raphaël Loll-Krippleber ◽  
Grant W. Brown ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acid ◽  
Genetic Disease ◽  
Elevated Temperatures ◽  
Temperature Sensitive ◽  
Wild Type ◽  
Standard Genetic Code ◽  
Gene Encoding ◽  
Chromatid Cohesion ◽  
Sensitive Allele

Mistranslation occurs when an amino acid not specified by the standard genetic code is incorporated during translation. Since the ribosome does not read the amino acid, tRNA variants aminoacylated with a non-cognate amino acid or containing a non-cognate anticodon dramatically increase the frequency of mistranslation. In a systematic genetic analysis, we identified a suppression interaction between tRNASerUGG, G26A, which mistranslates proline codons by inserting serine, and eco1-1, a temperature sensitive allele of the gene encoding an acetyltransferase required for sister chromatid cohesion. The suppression was partial, with a tRNA that inserts alanine at proline codons and not apparent for a tRNA that inserts serine at arginine codons. Sequencing of the eco1-1 allele revealed a mutation that would convert the highly conserved serine 213 within β7 of the GCN5-related N-acetyltransferase core to proline. Mutation of P213 in eco1-1 back to the wild-type serine restored the function of the enzyme at elevated temperatures. Our results indicate the utility of mistranslating tRNA variants to identify functionally relevant mutations and identify eco1 as a reporter for mistranslation. We propose that mistranslation could be used as a tool to treat genetic disease.

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