GENETIC EVIDENCE FOR 'DARWINIAN' SELECTION AT THE MOLECULAR LEVEL. I. THE EFFECT OF THE SUPPRESSIVE FACTOR ON CYTOPLASMICALLY-INHERITED ERYTHROMYCIN-RESISTANCE IN SACCHAROMYCES CEREVISIAE

1970 ◽  
Vol 12 (1) ◽  
pp. 129-136 ◽  
Author(s):  
Gerald H. Rank

A study of the suppressive factor of Saccharomyces cerevisiae and its effects on the transmission of cytoplasmically-inherited erythromycin resistance showed that loss of erythromycin resistance was contingent on suppressitivity, and that strains carrying the suppressive factor continuously segregated progeny cells that lacked resistance. It was suggested that suppressitivity is due to the presence, in suppressive strains, of rapidly-replicating abnormal mitochondrial DNA, and that loss of erythromycin resistance (coded for by normal mitochondrial DNA) is due to the replicative superiority of abnormal mitochondrial DNA.

1970 ◽  
Vol 12 (2) ◽  
pp. 340-346 ◽  
Author(s):  
Gerald H. Rank

A method was devised for the genetic analysis of cytoplasmically-inherited high and low suppressitivity in S. cervisiae thus enabling a test of the prediction, by the model of 'Darwinian' selection of mitochondrial DNA, that abnormal mitochondrial DNA of a high suppressitivity strain has a replicative advantage over abnormal mitochondrial DNA of a low suppressitivity strain. Support for the model was indicated by the ability of the suppressive factor resident in the high suppressitivity strain to control the phenotypic expression of suppressitivity in zygotes formed by crossing a low and high suppressitivity strain.


1972 ◽  
Vol 18 (1) ◽  
pp. 1-7 ◽  
Author(s):  
G. H. Rank ◽  
N. T. Bech-Hansen

Four nuclear and two cytoplasmic chloramphenicol-resistance markers were selected in S. cerevisiae. The effect of the suppressive factor (abnormal mitochondria deoxyribonucleic acid) on the inheritance of these markers was studied. Nuclear markers were shown to be unaffected by the suppressive factor, in contrast to the loss of cytoplasmically inherited chloramphenicol resistance upon the generation of the suppressive factor.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Silvia Bágeľová Poláková ◽  
Žaneta Lichtner ◽  
Tomáš Szemes ◽  
Martina Smolejová ◽  
Pavol Sulo

AbstractmtDNA recombination events in yeasts are known, but altered mitochondrial genomes were not completed. Therefore, we analyzed recombined mtDNAs in six Saccharomyces cerevisiae × Saccharomyces paradoxus hybrids in detail. Assembled molecules contain mostly segments with variable length introgressed to other mtDNA. All recombination sites are in the vicinity of the mobile elements, introns in cox1, cob genes and free standing ORF1, ORF4. The transplaced regions involve co-converted proximal exon regions. Thus, these selfish elements are beneficial to the host if the mother molecule is challenged with another molecule for transmission to the progeny. They trigger mtDNA recombination ensuring the transfer of adjacent regions, into the progeny of recombinant molecules. The recombination of the large segments may result in mitotically stable duplication of several genes.


2020 ◽  
Vol 85 (4) ◽  
pp. 895-901
Author(s):  
Takamitsu Amai ◽  
Tomoka Tsuji ◽  
Mitsuyoshi Ueda ◽  
Kouichi Kuroda

ABSTRACT Mitochondrial dysfunction can occur in a variety of ways, most often due to the deletion or mutation of mitochondrial DNA (mtDNA). The easy generation of yeasts with mtDNA deletion is attractive for analyzing the functions of the mtDNA gene. Treatment of yeasts with ethidium bromide is a well-known method for generating ρ° cells with complete deletion of mtDNA from Saccharomyces cerevisiae. However, the mutagenic effects of ethidium bromide on the nuclear genome cannot be excluded. In this study, we developed a “mito-CRISPR system” that specifically generates ρ° cells of yeasts. This system enabled the specific cleavage of mtDNA by introducing Cas9 fused with the mitochondrial target sequence at the N-terminus and guide RNA into mitochondria, resulting in the specific generation of ρ° cells in yeasts. The mito-CRISPR system provides a concise technology for deleting mtDNA in yeasts.


Genetics ◽  
2002 ◽  
Vol 162 (3) ◽  
pp. 1147-1156 ◽  
Author(s):  
Theodor Hanekamp ◽  
Mary K Thorsness ◽  
Indrani Rebbapragada ◽  
Elizabeth M Fisher ◽  
Corrine Seebart ◽  
...  

Abstract In the yeast Saccharomyces cerevisiae, certain mutant alleles of YME4, YME6, and MDM10 cause an increased rate of mitochondrial DNA migration to the nucleus, carbon-source-dependent alterations in mitochondrial morphology, and increased rates of mitochondrial DNA loss. While single mutants grow on media requiring mitochondrial respiration, any pairwise combination of these mutations causes a respiratory-deficient phenotype. This double-mutant phenotype allowed cloning of YME6, which is identical to MMM1 and encodes an outer mitochondrial membrane protein essential for maintaining normal mitochondrial morphology. Yeast strains bearing null mutations of MMM1 have altered mitochondrial morphology and a slow growth rate on all carbon sources and quantitatively lack mitochondrial DNA. Extragenic suppressors of MMM1 deletion mutants partially restore mitochondrial morphology to the wild-type state and have a corresponding increase in growth rate and mitochondrial DNA stability. A dominant suppressor also suppresses the phenotypes caused by a point mutation in MMM1, as well as by specific mutations in YME4 and MDM10.


1992 ◽  
Vol 12 (6) ◽  
pp. 2561-2569 ◽  
Author(s):  
L L Stohl ◽  
D A Clayton

Yeast mitochondrial DNA contains multiple promoters that sponsor different levels of transcription. Several promoters are individually located immediately adjacent to presumed origins of replication and have been suggested to play a role in priming of DNA replication. Although yeast mitochondrial DNA replication origins have not been extensively characterized at the primary sequence level, a common feature of these putative origins is the occurrence of a short guanosine-rich region in the priming strand downstream of the transcriptional start site. This situation is reminiscent of vertebrate mitochondrial DNA origins and raises the possibility of common features of origin function. In the case of human and mouse cells, there exists an RNA processing activity with the capacity to cleave at a guanosine-rich mitochondrial RNA sequence at an origin; we therefore sought the existence of a yeast endoribonuclease that had such a specificity. Whole cell and mitochondrial extracts of Saccharomyces cerevisiae contain an RNase that cleaves yeast mitochondrial RNA in a site-specific manner similar to that of the human and mouse RNA processing activity RNase MRP. The exact location of cleavage within yeast mitochondrial RNA corresponds to a mapped site of transition from RNA to DNA synthesis. The yeast activity also cleaved mammalian mitochondrial RNA in a fashion similar to that of the mammalian RNase MRPs. The yeast endonuclease is a ribonucleoprotein, as judged by its sensitivity to nucleases and proteinase, and it was present in yeast strains lacking mitochondrial DNA, which demonstrated that all components required for in vitro cleavage are encoded by nuclear genes. We conclude that this RNase is the yeast RNase MRP.


Genetics ◽  
2000 ◽  
Vol 154 (1) ◽  
pp. 147-154 ◽  
Author(s):  
Douglas J Kominsky ◽  
Peter E Thorsness

Abstract Organisms that can grow without mitochondrial DNA are referred to as “petite-positive” and those that are inviable in the absence of mitochondrial DNA are termed “petite-negative.” The petite-positive yeast Saccharomyces cerevisiae can be converted to a petite-negative yeast by inactivation of Yme1p, an ATP- and metal-dependent protease associated with the inner mitochondrial membrane. Suppression of this yme1 phenotype can occur by virtue of dominant mutations in the α- and γ-subunits of mitochondrial ATP synthase. These mutations are similar or identical to those occurring in the same subunits of the same enzyme that converts the petite-negative yeast Kluyveromyces lactis to petite-positive. Expression of YME1 in the petite-negative yeast Schizosaccharomyces pombe converts this yeast to petite-positive. No sequence closely related to YME1 was found by DNA-blot hybridization to S. pombe or K. lactis genomic DNA, and no antigenically related proteins were found in mitochondrial extracts of S. pombe probed with antisera directed against Yme1p. Mutations that block the formation of the F1 component of mitochondrial ATP synthase are also petite-negative. Thus, the F1 complex has an essential activity in cells lacking mitochondrial DNA and Yme1p can mediate that activity, even in heterologous systems.


2014 ◽  
Vol 25 (12) ◽  
pp. 1916-1924 ◽  
Author(s):  
David Öling ◽  
Rehan Masoom ◽  
Kristian Kvint

Ubp3 is a conserved ubiquitin protease that acts as an antisilencing factor in MAT and telomeric regions. Here we show that ubp3∆ mutants also display increased silencing in ribosomal DNA (rDNA). Consistent with this, RNA polymerase II occupancy is lower in cells lacking Ubp3 than in wild-type cells in all heterochromatic regions. Moreover, in a ubp3∆ mutant, unequal recombination in rDNA is highly suppressed. We present genetic evidence that this effect on rDNA recombination, but not silencing, is entirely dependent on the silencing factor Sir2. Further, ubp3∆ sir2∆ mutants age prematurely at the same rate as sir2∆ mutants. Thus our data suggest that recombination negatively influences replicative life span more so than silencing. However, in ubp3∆ mutants, recombination is not a prerequisite for aging, since cells lacking Ubp3 have a shorter life span than isogenic wild-type cells. We discuss the data in view of different models on how silencing and unequal recombination affect replicative life span and the role of Ubp3 in these processes.


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