Altered mitochondrial ribosomes in a cold-sensitive mutant of Saccharomyces cerevisiae

1978 ◽  
Vol 4 (2) ◽  
pp. 83-86 ◽  
Author(s):  
Terence W. Spithill ◽  
K. J. English ◽  
Phillip Nagley ◽  
Anthony W. Linnane
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Sensitive Mutant ◽  
Mitochondrial Ribosomes ◽  
Cold Sensitive

Putative GTPase Gtr1p genetically interacts with the RanGTPase cycle in Saccharomyces cerevisiae

1996 ◽  
Vol 109 (9) ◽  
pp. 2311-2318 ◽  
Author(s):  
N. Nakashima ◽  
N. Hayashi ◽  
E. Noguchi ◽  
T. Nishimoto
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Negative Regulator ◽  
Temperature Sensitive ◽  
Nucleotide Exchange ◽  
Sensitive Mutant ◽  
Temperature Sensitive Mutant ◽  
Importin Alpha ◽  
Nucleotide Exchange Factor ◽  
Cold Sensitive ◽  
Gtpase Cycle

In order to identify a protein interacting with RCC1, a guanine nucleotide-exchange factor for the nuclear GTPase Ran, we isolated a series of cold-sensitive suppressors of mtr1-2, a temperature-sensitive mutant of the Saccharomyces cerevisiae RCC1 homologue. One of the isolated suppressor mutants was mutated in the putative GTPase Gtr1p, being designated as gtr1-11. It also suppressed other alleles of mtr1-2, srm1-1 and prp20-1 in contrast to overexpression of the S. cerevisiae Ran/TC4 homologue Gsp1p, previously reported to suppress prp20-1, but not mtr1-2 or srm1-1. Furthermore, gtr1-11 suppressed the rna1-1, temperature-sensitive mutant of the Gsp1p GTPase-activating protein, but not the srp1-31, temperature-sensitive mutant of the S. cerevisiae importin alpha homologue. mtr1-2, srm1-1 and prp20-1 were also suppressed by overexpression of the mutated Gtr1p, Gtr1-11p. In summary, Gtr1p that was localized in the cytoplasm by immunofluoresence staining was suggested to function as a negative regulator for the Ran/TC4 GTPase cycle.

scholarly journals Interactions among three proteins that specifically activate translation of the mitochondrial COX3 mRNA in Saccharomyces cerevisiae.

1994 ◽  
Vol 14 (2) ◽  
pp. 1045-1053 ◽  
Author(s):  
N G Brown ◽  
M C Costanzo ◽  
T D Fox
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mitochondrial Membrane ◽  
Wild Type ◽  
Inner Mitochondrial Membrane ◽  
Mitochondrial Mutation ◽  
Mitochondrial Ribosomes ◽  
Functional Interactions ◽  
Cold Sensitive ◽  
Two Hybrid ◽  
Missense Substitution

The PET54, PET122, and PET494 proteins, which are associated with the yeast inner mitochondrial membrane, specifically activate translation of the mitochondrially encoded COX3 mRNA. We used the two-hybrid system to test whether pairs of these proteins, when fused to either the GAL4 DNA-binding or transcriptional activating domain, can physically associate as measured by the expression of the GAL4-dependent reporter, lacZ. PET54 and PET122 interacted in this system, and an amino-terminally truncated PET494 fragment showed an interaction with PET54. We also detected functional interactions between PET54 and PET122 genetically: a pet54 missense substitution (Phe to Gly at position 244) that caused a severe respiratory defect was suppressed both by a missense substitution affecting PET122 (Gly to Val at position 211) and by overproduction of wild-type PET122. Both Gly and Ala, substituted at PET54 position 244, disrupted the two-hybrid interactions with PET122 and PET494. While Ala at PET54 position 244 caused only a modest respiratory phenotype alone, it caused a severe respiratory defect when combined with a cold-sensitive mitochondrial mutation affecting the COX3 mRNA 5' leader. This synthetic defect was suppressed by a missense substitution in PET122 and by overproduction of wild-type PET122, indicating functional interactions among PET54, PET122, and the mRNA. Taken together with previous work, these data suggest that a complex containing PET54, PET122, and PET494 mediates the interaction of the COX3 mRNA with mitochondrial ribosomes at the surface of the inner membrane.

CDC55, a Saccharomyces cerevisiae gene involved in cellular morphogenesis: identification, characterization, and homology to the B subunit of mammalian type 2A protein phosphatase

1991 ◽  
Vol 11 (11) ◽  
pp. 5767-5780
Author(s):  
A M Healy ◽  
S Zolnierowicz ◽  
A E Stapleton ◽  
M Goebl ◽  
A A DePaoli-Roach ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Phosphatase ◽  
Protein A ◽  
Cdna Clones ◽  
Restrictive Temperature ◽  
B Subunit ◽  
Bud Emergence ◽  
New Gene ◽  
Cold Sensitive ◽  
Polymerase Chain

Microscopic screening of a collection of cold-sensitive mutants of Saccharomyces cerevisiae led to the identification of a new gene, CDC55, which appears to be involved in the morphogenetic events of the cell cycle. CDC55 maps between CDC43 and CHC1 on the left arm of chromosome VII. At restrictive temperature, the original cdc55 mutant produces abnormally elongated buds and displays a delay or partial block of septation and/or cell separation. A cdc55 deletion mutant displays a cold-sensitive phenotype like that of the original isolate. Sequencing of CDC55 revealed that it encodes a protein of about 60 kDa, as confirmed by Western immunoblots using Cdc55p-specific antibodies. This protein has greater than 50% sequence identity to the B subunits of rabbit skeletal muscle type 2A protein phosphatase; the latter sequences were obtained by analysis of peptides derived from the purified protein, a polymerase chain reaction product, and cDNA clones. An extragenic suppressor of the cdc55 mutation lies in BEM2, a gene previously identified on the basis of an apparent role in bud emergence.

Isolation of the thymidylate synthetase gene (TMP1) by complementation in Saccharomyces cerevisiae

1982 ◽  
Vol 2 (4) ◽  
pp. 437-442
Author(s):  
G R Taylor ◽  
B J Barclay ◽  
R K Storms ◽  
J D Friesen ◽  
R H Haynes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
High Frequency ◽  
Wild Type Strain ◽  
Biologically Active ◽  
Thymidylate Synthetase ◽  
Temperature Sensitive ◽  
Synthetase Activity ◽  
Enzymatic Conversion ◽  
Wild Type ◽  
Sensitive Mutant

The structural gene (TMP1) for yeast thymidylate synthetase (thymidylate synthase; EC 2.1.1.45) was isolated from a chimeric plasmid bank by genetic complementation in Saccharomyces cerevisiae. Retransformation of the dTMP auxotroph GY712 and a temperature-sensitive mutant (cdc21) with purified plasmid (pTL1) yielded Tmp+ transformants at high frequency. In addition, the plasmid was tested for the ability to complement a bacterial thyA mutant that lacks functional thymidylate synthetase. Although it was not possible to select Thy+ transformants directly, it was found that all pTL1 transformants were phenotypically Thy+ after several generations of growth in nonselective conditions. Thus, yeast thymidylate synthetase is biologically active in Escherichia coli. Thymidylate synthetase was assayed in yeast cell lysates by high-pressure liquid chromatography to monitor the conversion of [6-3H]dUMP to [6-3H]dTMP. In protein extracts from the thymidylate auxotroph (tmp1-6) enzymatic conversion of dUMP to dTMP was barely detectable. Lysates of pTL1 transformants of this strain, however, had thymidylate synthetase activity that was comparable to that of the wild-type strain.

scholarly journals Either of the major H2A genes but not an evolutionarily conserved H2A.F/Z variant of Tetrahymena thermophila can function as the sole H2A gene in the yeast Saccharomyces cerevisiae.

1996 ◽  
Vol 16 (6) ◽  
pp. 2878-2887 ◽  
Author(s):  
X Liu ◽  
J Bowen ◽  
M A Gorovsky
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Tetrahymena Thermophila ◽  
Yeast Species ◽  
Budding Yeast ◽  
Yeast Cells ◽  
Ciliated Protozoan ◽  
Yeast Saccharomyces Cerevisiae ◽  
Evolutionarily Conserved ◽  
Cold Sensitive ◽  
Conserved Epitope

H2A.F/Z histones are conserved variants that diverged from major H2A proteins early in evolution, suggesting they perform an important function distinct from major H2A proteins. Antisera specific for hv1, the H2A.F/Z variant of the ciliated protozoan Tetrahymena thermophila, cross-react with proteins from Saccharomyces cerevisiae. However, no H2A.F/Z variant has been reported in this budding yeast species. We sought to distinguish among three explanations for these observations: (i) that S. cerevisiae has an undiscovered H2A.F/Z variant, (ii) that the major S. cerevisiae H2A proteins are functionally equivalent to H2A.F/Z variants, or (iii) that the conserved epitope is found on a non-H2A molecule. Repeated attempts to clone an S. cerevisiae hv1 homolog only resulted in the cloning of the known H2A genes yHTA1 and yHTA2. To test for functional relatedness, we attempted to rescue strains lacking the yeast H2A genes with either the Tetrahymena major H2A genes (tHTA1 or tHTA2) or the gene (tHTA3) encoding hv1. Although they differ considerably in sequence from the yeast H2A genes, the major Tetrahymena H2A genes can provide the essential functions of H2A in yeast cells, the first such case of trans-species complementation of histone function. The Tetrahymena H2A genes confer a cold-sensitive phenotype. Although expressed at high levels and transported to the nucleus, hv1 cannot replace yeast H2A proteins. Proteins from S. cerevisiae strains lacking yeast H2A genes fail to cross-react with anti-hv1 antibodies. These studies make it likely that S. cerevisiae differs from most other eukaryotes in that it does not have an H2A.F/Z homolog. A hypothesis is presented relating the absence of H2A.F/Z in S. cerevisiae to its function in other organisms.

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