We have inserted a yeast nuclear DNA fragment bearing the TRP1 gene and its associated origin of DNA replication, ARS1, into the functional mitochondrial chromosome of a strain carrying a chromosomal trp1 deletion. TRP1 was not phenotypically expressed within the organelle. However, this Trp- strain readily gave rise to respiratory competent Trp+ clones that contained the TRP1/ARS1 fragment, associated with portions of mitochondrial DNA (mtDNA), replicating in their nuclei. Thus the Trp+ clones arose as a result of DNA escaping from mitochondria and migrating to the nucleus. We have isolated 21 nuclear mutants in which the rate of mtDNA escape is increased by screening for increased rates of papillation to Trp+. All 21 mutations were recessive and fell into six complementation groups, termed YME1-YME6. In addition to increasing the rate of mtDNA escape, yme1 mutations also caused a heat-sensitive respiratory deficient phenotype at 37 degrees and a cold-sensitive growth defect on complete glucose medium at 14 degrees. While the other yme mutations had no detectable growth phenotypes, synergistic interactions were observed in two double mutant combinations: a yme1, yme2 double mutant failed to respire at 30 degrees and a yme4, yme6 double mutant failed to respire at all temperatures tested. None of the respiratory defects were caused by loss of functional mtDNA. These findings suggest that yme1, yme2, yme4 and yme6 mutations alter mitochondrial functions and thereby lead to an increased rate of DNA escape from the organelle.
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Gene | Phenotype | Experiment Type | Mutant Information | Strain Background | Chemical | Details |
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YME1 | cold sensitivity: increased | classical genetics | null Allele: yme1-1 | D273-10B | Media: glucose Temperature: reduced temperature, 14 °C Details: unable to grow on rich glucose medium, but able to grow on glycerol, a non-fermentable carbon source, at reduced temperature | |
YME1 | mitochondrial genome maintenance: decreased | classical genetics | null Allele: yme1-1 | D273-10B | Details: 25-fold increase in the rate of escape and migration of DNA from mitochondria to the nucleus, using a tryptophan auxotroph with TRP1 integrated into the mt genome and assaying for mutants with increased papillation to Trp+ based on transfer of the TRP1 gene to the nucleus | |
YME2 | mitochondrial genome maintenance: decreased | classical genetics | null Allele: yme2-1 nonsense mutation at codon 282, resulting in a truncation prior to the TMD and exonuclease motifs | D273-10B | Details: 8-fold increase in the rate of escape and migration of DNA from mitochondria to the nucleus, using a tryptophan auxotroph with TRP1 integrated into the mt genome and assaying for mutants with increased papillation to Trp+ based on transfer of the TRP1 gene to the nucleus | |
VPS13 | mitochondrial genome maintenance: decreased | classical genetics | null Allele: vps13-31 -1 frameshift; deletion of nt G1565, truncates the protein from 3144 to 533 amino acids | D273-10B | Details: 10-fold increase in the rate of escape and migration of DNA from mitochondria to the nucleus, using a tryptophan auxotroph with TRP1 integrated into the mt genome and assaying for mutants with increased papillation to Trp+ based on transfer of the TRP1 gene to the nucleus | |
MMM1 | mitochondrial genome maintenance: decreased | classical genetics | reduction of function Allele: mmm1-6 E215K | D273-10B | Details: 12-fold increase in the rate of escape and migration of DNA from mitochondria to the nucleus, using a tryptophan auxotroph with TRP1 integrated into the mt genome and assaying for mutants with increased papillation to Trp+ based on transfer of the TRP1 gene to the nucleus | |
YME1 | respiratory growth: absent | classical genetics | null Allele: yme1-1 | D273-10B | Media: non-fermentable carbon source Temperature: elevated temperature, 37 °C Details: required for respiratory growth at elevated temperature |
Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details about experiment type and any other genes involved in the interaction.
Evidence ID | Analyze ID | Interactor | Interactor Systematic Name | Interactor | Interactor Systematic Name | Allele | Assay | Annotation | Action | Phenotype | SGA score | P-value | Source | Reference | Note |
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Increase the total number of rows showing on this page by using the pull-down located below the table, or use the page scroll at the table's top right to browse through the table's pages; use the arrows to the right of a column header to sort by that column; filter the table using the "Filter" box at the top of the table; click on the small "i" buttons located within a cell for an annotation to view further details about experiment type and any other genes involved in the interaction.