MOVING-PICTURES AND PULSED-FIELD GEL-ELECTROPHORESIS SHOW ONLY LINEARMITOCHONDRIAL-DNA MOLECULES FROM YEASTS WITH LINEAR-MAPPING AND CIRCULAR-MAPPING MITOCHONDRIAL GENOMES
Ma. Jacobs et al., MOVING-PICTURES AND PULSED-FIELD GEL-ELECTROPHORESIS SHOW ONLY LINEARMITOCHONDRIAL-DNA MOLECULES FROM YEASTS WITH LINEAR-MAPPING AND CIRCULAR-MAPPING MITOCHONDRIAL GENOMES, Current genetics, 30(1), 1996, pp. 3-11
The mobility of mitochondrial DNA (mtDNA) in pulsed-field gel electrop
horesis (PFGE) and its appearance in moving pictures from fluorescence
microscopy were used to investigate the mitochondrial genome structur
e for five Pichia and Williopsis strains of yeast. An apocytochrome b-
gene hybridization probe identified only linear mtDNA molecules for ea
ch strain when total cellular DNA was fractionated by PFGE. Most of th
e mass of DNA isolated from mitochondria for one linear-mapping and on
e circular-mapping mitochondrial genome was found in linear molecules
much larger than the genome size of 50 kb; some molecules were as long
as 1500 kb, but only a trace amount of apparently circular mtDNA was
found for the strain with the circular-mapping genome. Probes for both
the apocytochrome-b and mitochondrial small rRNA sub-unit genes hybri
dized strongly to mtDNA of approximately 50-100 kb, but weakly to the
larger DNA from mitochondria of these two strains. For the four linear
-mapping strains, PFGE revealed two or three distinct bands of linear
mtDNA, larger than the genome size, within a smear of approximately 50
-100 kb, but a smear without bands was found for the circular-mapping
strain.