The isolation and properties of a DNA-directed RNA polymerase from yeast mitochondria

Isolation and characterization of a multienzyme complex containing DNA replicative enzymes from mitochondria of S. cerevisiae. Multienzyme complex from yeast mitochondria

A 40 S multienzyme complex containing mtDNA polymerase was isolated from mitochondria of S. cerevisiae by density gradient centrifugation and by gel filtration chromatography. Besides DNA polymerase, RNA polymerase, primase, 3'-->5' exonuclease and an ATPase activities were found to be associated with it. The presence of some of these enzymes were confirmed by Western blot. This high molecular weight multienzyme complex containing DNA has most of the attributes of a putative replisome.

Yeast RPO41 gene product is required for transcription and maintenance of the mitochondrial genome

A 4-kilobase DNA fragment carried by a recombinant lambda gt11 bacteriophage appears to contain most of the coding information for the 145-kDa subunit of the Saccharomyces cerevisiae mitochondrial RNA polymerase. The RPO41 gene is located on chromosome VI, as determined by hybridization to electrophoretically separated yeast chromosomes. Hybridization and gene disruption/replacement experiments show that the RPO41 gene exists in a single copy and that its product is required for transcription and maintenance of the mitochondrial genome.

Germ-tube formation by atypical strains of Candida albicans

Atypical isolates of Candida albicans which failed to produce germ tubes in routine diagnostic procedures were examined for their ability to produce germ tubes in various media. Bovine serum was more effective than defined media for induction of germ tubes in the majority of isolates. A few strains formed appreciable germ tubes only in bovine serum with added thioglycollate or cysteine. One strain did not produce germ tubes in any medium. Germ-tube maturation appeared to be dependent upon mitochondrial RNA polymerase activity. The failure by an isolate to produce germ tubes, particularly in tests without strictly controlled conditions, does not preclude the possibility that the organism is C. albicans.