Abstract
Denatured mitochondrial DNA (mtDNA) from a grande (wild-type) yeast strain and a series of derived genetically characterized cytoplasmic petite mutants was examined in the electron microscope as DNA-protein monolayers prepared under conditions that permitted little bimolecular renaturation. In the grande and some petite strains, the mtDNA remained predominantly single-stranded. However, in several petite strains, a large proportion of molecules contained double-stranded segments indicative of unimolecular renaturation due to the presence of inverted repeat sequences. The length of the double-stranded segments of strain E41 was compared to the periodicity seen on denaturation maps. A repeat spacing twice the length of the inverted repeats was observed in the denaturation map. Inverted repeat length was similar to contour length of circular mtDNA molecules in this strain. On the basis of these observations most of the mtDNA from petite strain E41 appeared to consist of polymers of tandem inverted repeats interspersed with a small single-stranded “spacer” sequence between the repeat segments. In contrast, petite strain F13 mtDNA had few or no inverted repeats and showed a regular periodicity of 0.14 μm in the denaturation map, similar in length to the 0.13-μm circles present in the isolated mtDNA.
Keywords: unimolecular renaturation, electron microscopy, molecular configuration, denaturation mapping, repeat spacing
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- Borst P. Mitochondrial nucleic acids. Annu Rev Biochem. 1972;41:333–376. doi: 10.1146/annurev.bi.41.070172.002001. [DOI] [PubMed] [Google Scholar]
- Cohen M., Casey J., Rabinowitz M., Getz G. S. Hybridization of mitochondrial transfer RNA and mitochondrial DNA in petite mutants of yeast. J Mol Biol. 1972 Feb 14;63(3):441–451. doi: 10.1016/0022-2836(72)90439-1. [DOI] [PubMed] [Google Scholar]
- Cohen M., Rabinowitz M. Analysis of grande and petite yeast mitochondrial DNA by tRNA hybridization. Biochim Biophys Acta. 1972 Oct 11;281(2):192–201. doi: 10.1016/0005-2787(72)90171-2. [DOI] [PubMed] [Google Scholar]
- Davis R. W., Hyman R. W. A study in evolution: the DNA base sequence homology between coliphages T7 and T3. J Mol Biol. 1971 Dec 14;62(2):287–301. doi: 10.1016/0022-2836(71)90428-1. [DOI] [PubMed] [Google Scholar]
- Faye G., Fukuhara H., Grandchamp C., Lazowska J., Michel F., Casey J., Getz G. S., Locker J., Rabinowitz M., Bolotin-Fukuhara M. Mitochondrial nucleic acids in the petite colonie mutants: deletions and repetition of genes. Biochimie. 1973;55(6):779–792. doi: 10.1016/s0300-9084(73)80030-6. [DOI] [PubMed] [Google Scholar]
- Gordon P., Casey J., Rabinowitz M. Characterization of mitochondrial deoxyribonucleic acid from a series of petite yeast strains by deoxyribonucleic acid-deoxyribonucleic acid hybridization. Biochemistry. 1974 Mar 12;13(6):1067–1075. doi: 10.1021/bi00703a002. [DOI] [PubMed] [Google Scholar]
- Gordon P., Rabinowitz M. Evidence for deletion and changed sequence in the mitochondrial deoxyribonucleic acid of a spontaneously generated petite mutant of Saccharomyces cerevisiae. Biochemistry. 1973 Jan 2;12(1):116–123. doi: 10.1021/bi00725a019. [DOI] [PubMed] [Google Scholar]
- Hollenberg C. P., Borst P., van Bruggen E. F. Mitochondrial DNA. V. A 25 micron closed circular duplex DNA molecule in wild-type yeast mitochondria. Stucture and genetic complexity. Biochim Biophys Acta. 1970 May 21;209(1):1–15. [PubMed] [Google Scholar]
- Inman R. B. Denaturation maps of the left and right sides of the lambda DNA molecule determined by electron microscopy. J Mol Biol. 1967 Aug 28;28(1):103–116. doi: 10.1016/s0022-2836(67)80081-0. [DOI] [PubMed] [Google Scholar]
- Sanders J. P., Flavell R. A., Borst P., Mol J. N. Nature of the base sequence conserved in the mitochondrial DNA of a low-density petite. Biochim Biophys Acta. 1973 Jul 13;312(3):441–457. doi: 10.1016/0005-2787(73)90443-7. [DOI] [PubMed] [Google Scholar]