scholarly journals MITOCHONDRIAL GENETICS IX: A MODEL FOR RECOMBINATION AND SEGREGATION OF MITOCHONDRIAL GENOMES IN SACCHAROMYCES CEREVISIAE

Genetics ◽  
1974 ◽  
Vol 78 (1) ◽  
pp. 415-437
Author(s):  
B Dujon ◽  
P P Slonimski ◽  
L Weill
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.


Genetics ◽  
1974 ◽  
Vol 76 (2) ◽  
pp. 195-219
Author(s):  
J Deutsch ◽  
B Dujon ◽  
P Netter ◽  
E Petrochilo ◽  
P P Slonimski ◽  
...  

ABSTRACT The survival of the ρ+ factor and of DrugR mitochondrial genetic markers after exposure to ethidium bromide has been studied. A technique allowing the determination of DrugR genetic markers among a great number of both grande and petite colonies has been developed. The results have been analyzed by the target theory. The survival of the ρ+ factor is always less than the survival of any DrugR genetic marker. The survivals of CR and ER are similar to each other, while that of OR is greater than that of the other two DrugR markers. All possible combinations of DrugR markers have been found among the ρ- petite cells induced, while the only type found among the grande colonies is the preexisting one. The loss of the CR and ER genetic markers was found to be the most frequently concomitant, while the correlation between the loss of the OR marker and the other two DrugR markers is less strong. Similar results have been obtained after U.V. irradiation. Interpretations concerning the structure of the yeast mitochondrial genome are given and hypotheses on the mechanism of petite mutation discussed.


2021 ◽  
Vol 12 ◽  
Author(s):  
Ajibola B. Bakare ◽  
Edward J. Lesnefsky ◽  
Shilpa Iyer

Leigh syndrome is a rare, complex, and incurable early onset (typically infant or early childhood) mitochondrial disorder with both phenotypic and genetic heterogeneity. The heterogeneous nature of this disorder, based in part on the complexity of mitochondrial genetics, and the significant interactions between the nuclear and mitochondrial genomes has made it particularly challenging to research and develop therapies. This review article discusses some of the advances that have been made in the field to date. While the prognosis is poor with no current substantial treatment options, multiple studies are underway to understand the etiology, pathogenesis, and pathophysiology of Leigh syndrome. With advances in available research tools leading to a better understanding of the mitochondria in health and disease, there is hope for novel treatment options in the future.


Biology ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 358
Author(s):  
Ryan R. Cochrane ◽  
Stephanie L. Brumwell ◽  
Arina Shrestha ◽  
Daniel J. Giguere ◽  
Samir Hamadache ◽  
...  

Algae are attractive organisms for biotechnology applications such as the production of biofuels, medicines, and other high-value compounds due to their genetic diversity, varied physical characteristics, and metabolic processes. As new species are being domesticated, rapid nuclear and organelle genome engineering methods need to be developed or optimized. To that end, we have previously demonstrated that the mitochondrial genome of microalgae Phaeodactylum tricornutum can be cloned and engineered in Saccharomyces cerevisiae and Escherichia coli. Here, we show that the same approach can be used to clone mitochondrial genomes of another microalga, Thalassiosira pseudonana. We have demonstrated that these genomes can be cloned in S. cerevisiae as easily as those of P. tricornutum, but they are less stable when propagated in E. coli. Specifically, after approximately 60 generations of propagation in E. coli, 17% of cloned T. pseudonana mitochondrial genomes contained deletions compared to 0% of previously cloned P. tricornutum mitochondrial genomes. This genome instability is potentially due to the lower G+C DNA content of T. pseudonana (30%) compared to P. tricornutum (35%). Consequently, the previously established method can be applied to clone T. pseudonana’s mitochondrial genome, however, more frequent analyses of genome integrity will be required following propagation in E. coli prior to use in downstream applications.


2018 ◽  
Vol 6 (17) ◽  
Author(s):  
Delphine Naquin ◽  
Cristina Panozzo ◽  
Geneviève Dujardin ◽  
Erwin van Dijk ◽  
Yves d’Aubenton-Carafa ◽  
...  

ABSTRACT The mitochondrial genomes of Saccharomyces cerevisiae strains contain up to 13 introns. An intronless recombinant genome introduced into the nuclear background of S. cerevisiae strain W303 gave the S. cerevisiae CW252 strain, which is used to model mitochondrial respiratory pathologies. The complete sequence of this mitochondrial genome was obtained using a hybrid assembling methodology.


2000 ◽  
Vol 46 (11) ◽  
pp. 1058-1065 ◽  
Author(s):  
Domenica Rita Massardo ◽  
Stephan G Zweifel ◽  
Norio Gunge ◽  
Isamu Miyakawa ◽  
Nobundo Sando ◽  
...  

In the yeast Saccharomyces cerevisiae, mutants are viable with large deletions (rho-), or even complete loss of the mitochondrial genome (rho0). One class of rho- mutants, which is called hypersuppressive, is characterised by a high transmission of the mutated mitochondrial genome to the diploid progeny when mated to a wild-type (rho+) haploid. The nuclear gene CCE1 encodes a cruciform cutting endonuclease, which is located in the mitochondrion and is responsible for the highly biased transmission of the hypersuppressive rho- genome. CCE1 is a Holliday junction specific endonuclease that resolves recombination intermediates in mitochondrial DNA. The cleavage activity shows a strong preference for cutting after a 5'-CT dinucleotide. In the absence of the CCE1 gene product, the mitochondrial genomes remain interconnected and have difficulty segregating to the daughter cells. As a consequence, there is an increase in the fraction of daughter cells that are rho0. In this paper we demonstrate the usefulness of lycorine, together with staining by 4',6-diamidino-2-phenylindole (DAPI), to assay for the mitotic stability of a variety of mitochondrial genomes. We have found that rho+ and rho- strains that contain CT sequences produce a large fraction of rho0 progeny in the absence of CCE1 activity. Only those rho- mitochondrial genomes lacking the CT recognition sequence are unaffected by the cce1 allele.Key words: yeast, mitochondria, hypersuppressive, Saccharomyces cerevisiae, lycorine.


Genetics ◽  
1985 ◽  
Vol 111 (3) ◽  
pp. 389-402
Author(s):  
R J Evans ◽  
K M Oakley ◽  
G D Clark-Walker

ABSTRACT When recently arisen spontaneous petite mutants of Saccharomyces cerevisiae are crossed, respiratory competent diploids can be recovered. Such restored strains can be divided into two groups having sectored or unsectored colony morphology, the former being due to an elevated level of spontaneous petite mutation. On the basis of petite frequency, the sectored strains can be subdivided into those with a moderate frequency (5-16%) and those with a high frequency (>60%) of petite formation. Each of the three categories of restored strains can be found on crossing two petites, suggesting either that the parental mutants contain a heterogeneous population of deleted mtDNAs at the time of mating or that different interactions can occur between the defective molecules. Restriction endonuclease analysis of mtDNA from restored strains that have a wild-type petite frequency showed that they had recovered a wild-type mtDNA fragmentation pattern. Conversely, all examined cultures from both categories of sectored strains contained aberrant mitochondrial genomes that were perpetuated without change over at least 200 generations. In addition, sectored colony siblings can have different aberrant mtDNAs. The finding that two sectored, restored strains from different crosses have identical but aberrant mtDNAs provides evidence for preferred deletion sites from the mitochondrial genome. Although it appears that mtDNAs from sectored strains invariably contain duplications, there is no apparent correlation between the size of the duplication and spontaneous petite frequency.


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