AUTHOR=Špírek Mário , Poláková Silvia , Jatzová Katarína , Sulo Pavol 

TITLE=Post-zygotic sterility and cytonuclear compatibility limits in S. cerevisiae xenomitochondrial cybrids

JOURNAL=Frontiers in Genetics

VOLUME=5

YEAR=2015

URL=https://www.frontiersin.org/journals/genetics/articles/10.3389/fgene.2014.00454

DOI=10.3389/fgene.2014.00454

ISSN=1664-8021

ABSTRACT=<p>Nucleo-mitochondrial interactions, particularly those determining the primary divergence of biological species, can be studied by means of xenomitochondrial cybrids, which are cells where the original mitochondria are substituted by their counterparts from related species. <italic>Saccharomyces cerevisiae</italic> cybrids are prepared simply by the mating of the ρ<sup>0</sup> strain with impaired karyogamy and germinating spores from other <italic>Saccharomyces</italic> species and fall into three categories. Cybrids with compatible mitochondrial DNA (mtDNA) from <italic>Saccharomyces paradoxus</italic> CBS 432 and <italic>Saccharomyces cariocanus</italic> CBS 7994 are metabolically and genetically similar to cybrids containing mtDNA from various <italic>S. cerevisiae.</italic> Cybrids with mtDNA from other <italic>S. paradoxus</italic> strains<italic>, S. cariocanus, Saccharomyces kudriavzevii, and Saccharomyces mikatae</italic> require a period of adaptation to establish efficient oxidative phosphorylation. They exhibit a temperature-sensitive phenotype, slower growth rate on a non-fermentable carbon source and a long lag phase after the shift from glucose. Their decreased respiration capacity and reduced cytochrome <italic>aa3</italic> content is associated with the inefficient splicing of <italic>cox1</italic>I3β, the intron found in all <italic>Saccharomyces</italic> species but not in <italic>S. cerevisiae.</italic> The splicing defect is compensated in cybrids by nuclear gain-of-function and can be alternatively suppressed by overexpression of <italic>MRP13</italic> gene for mitochondrial ribosomal protein or the <italic>MRS2, MRS3</italic>, and <italic>MRS4</italic> genes involved in intron splicing. <italic>S. cerevisiae</italic> with <italic>Saccharomyces bayanus</italic> mtDNA is unable to respire and the growth on ethanol–glycerol can be restored only after mating to some <italic>mit</italic><sup>−</sup> strains. The nucleo-mitochondrial compatibility limit of <italic>S. cerevisiae</italic> and other <italic>Saccharomyces</italic> was set between <italic>S. kudriavzevii</italic> and <italic>S. bayanus</italic> at the divergence from <italic>S. cerevisiae</italic> about 15 MYA. The <italic>MRS1-cox1 S. cerevisiae</italic>/<italic>S. paradoxus</italic> cytonuclear Dobzhansky–Muller pair has a neglible impact on the separation of species since its imperfection is compensated for by gain-of-function mutation.</p>