title: Deletions and rearrangements in Kluyveromyces lactis mitochondrial DNA.
abstract: Three classes of respiratory deficient mutants have been isolated from a fusant between Kluyveromyces lactis and Saccharomyces cerevisiae that contains only K. lactis mtDNA. One class (15 isolates), resemble rho 0 mutants of S. cerevisiae as they lack detectable mtDNA. A second class (16 isolates), resemble point mutations (mit-) or nuclear lesions (pet-) of S. cerevisiae as no detectable change is found in their mtDNA. The third class (five isolates), with deletions and rearrangements in their mtDNA are comparable to S. cerevisiae petite (rho-) mutants. Surprisingly, three of the five deletion mutants have lost the same 8.0 kb sector of the mtDNA that encompasses the entire cytochrome oxidase subunit 2 gene and the majority of the adjacent cytochrome oxidase subunit 1 gene. In the other strains, deletions are accompanied by complex rearrangements together with substoiciometric bands and in one instance an amplified sector of 800 bp. By contrast to G + C rich short direct repeats forming deletion sites in S. cerevisiae mtDNA, excision of the 8.0 kb sector in K. lactis mtDNA occurs at an 11 bp A + T rich direct repeat CTAATATATAT. The recovery of three strains manifesting this deletion suggests there are limited sites for intramolecular recombination leading to excision in K. lactis mtDNA.
authors.affiliation: Molecular and Population Genetics Group, Research School of Biological Sciences, Australian National University, Canberra, A.C.T.
authors.forename: C M
authors.initials: CM
authors.lastname: Hardy
authors.forename: C L
authors.initials: CL
authors.lastname: Galeotti
authors.forename: G D
authors.initials: GD
authors.lastname: Clark-Walker
mesh_terms: D001483:Base Sequence; D002872:Chromosome Deletion; D003580:Cytochromes / Q000032:analysis; D004271:DNA, Fungal / Q000235:genetics; D004272:DNA, Mitochondrial / Q000235:genetics*; D015321:Gene Rearrangement; D007716:Kluyveromyces / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics; D004718:Saccharomycetales / Q000235:genetics*
chemical_list: D003580:Cytochromes; D004271:DNA, Fungal; D004272:DNA, Mitochondrial