title: Adaptive expression responses in the Pol-gamma null strain of S. pombe depleted of mitochondrial genome.
abstract: BACKGROUND
  DNA polymerase gamma(Pol-gamma) has been shown to be essential for maintenance of the mitochondrial genome (mtDNA) in the petite-positive budding yeast Saccharomyces cerevisiae. Budding yeast cells lacking mitochondria exhibit a slow-growing or petite-colony phenotype. Petite strains fail to grow on non-fermentable carbon sources. However, it is not clear whether the Pol-gamma is required for mtDNA maintenance in the petite-negative fission yeast Schizosaccharomyces pombe.
  
  
  RESULTS
  We show that disruption of the nuclear gene pog1+ that encodes Pol-gamma is sufficient to deplete mtDNA in S. pombe. Cells bearing pog1Delta allele require substantial growth periods to form petite colonies. Mitotracker assays indicate that pog1Delta cells are defective in mitochondrial function and EM analyses suggest that pog1Delta cells lack normal mitochondrial structures. Depletion of mtDNA in pog1Delta cells is evident from quantitative real-time PCR assays. Genome-wide expression profiles of pog1Delta and other mtDNA-less cells reveal that many genes involved in response to stimulus, energy derivation by oxidation of organic compounds, cellular carbohydrate metabolism, and energy reserve metabolism are induced. Conversely, many genes encoding proteins involved in amino acid metabolism and oxidative phosphorylation are repressed.
  
  
  CONCLUSIONS
  By showing that Pol-gamma is essential for mtDNA maintenance and disruption of pog1+ alters the genome-wide expression profiles, we demonstrated that cells lacking mtDNA exhibit adaptive nuclear gene expression responses in the petite-negative S. pombe.
authors.affiliation: Systems Biology, Genome Institute of Singapore, Singapore 138672, Singapore. chuz@gis.a-star.edu.sg
authors.forename: Zhaoqing
authors.initials: Z
authors.lastname: Chu
authors.forename: Juntao
authors.initials: J
authors.lastname: Li
authors.forename: Majid
authors.initials: M
authors.lastname: Eshaghi
authors.forename: R Krishna Murthy
authors.initials: RK
authors.lastname: Karuturi
authors.forename: Kui
authors.initials: K
authors.lastname: Lin
authors.forename: Jianhua
authors.initials: J
authors.lastname: Liu
mesh_terms: D000814:Aniline Compounds / Q000378:metabolism; D002473:Cell Wall / Q000378:metabolism; D000074002:DNA Polymerase gamma; D004272:DNA, Mitochondrial / Q000235:genetics*; D004259:DNA-Directed DNA Polymerase / Q000235:genetics*; D005456:Fluorescent Dyes / Q000378:metabolism; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D007211:Indoles / Q000378:metabolism; D008957:Models, Genetic; D010802:Phylogeny; D012568:Schizosaccharomyces / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure
chemical_list: D000814:Aniline Compounds; D004272:DNA, Mitochondrial; D005456:Fluorescent Dyes; D007211:Indoles; C007293:DAPI; D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase; C023650:aniline