Abstract
Photosynthesis-deficient mutants of the green alga Chlamydomonas reinhardtii were previously shown to arise from nonsense mutations within the chloroplast rbcL gene, which encodes the large subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (EC 4.1.1.39). Photosynthesis-competent revertants of these nonsense mutants have often been found to be stably heteroplasmic, giving rise to both mutant and revertant cells during mitotic or meiotic divisions under nonselective growth conditions. It was proposed that the stable heteroplasmicity might arise from a balanced polymorphism of suppressor and wild-type alleles of a tRNA gene maintained within the polyploid chloroplast genome. In the present study, we have focused on determining the molecular basis for the heteroplasmicity of one such revertant, named R13-3C, which was recovered from the 18-7G amber (UAG) mutant. Restriction-enzyme analysis and DNA sequencing showed that the amber mutation is still present in the rbcL gene of the revertant strain. In contrast, DNA sequencing of the suspected tRNA(Trp) gene of the revertant revealed a mutation that would change its CCA anticodon to amber-specific CUA. This mutation was found to be heteroplasmic, being present in only 70% of the tRNA(Trp) gene copies. Under nonselective conditions, the suppressor mutation was lost from cells that also lost the revertant phenotype. We conclude that stable heteroplasmicity can arise as a balanced polymorphism of organellar alleles. This observation suggests that additional tRNA suppressors may be identified due to their heteroplasmic nature within polyploid genomes.
Full text
PDF



Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Atkin A. L., Roy K. L., Bell J. B. Construction of an opal suppressor by oligonucleotide-directed mutagenesis of a Saccharomyces cerevisiae tRNA(Trp) gene. Mol Cell Biol. 1990 Aug;10(8):4379–4383. doi: 10.1128/mcb.10.8.4379. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Attardi G., Schatz G. Biogenesis of mitochondria. Annu Rev Cell Biol. 1988;4:289–333. doi: 10.1146/annurev.cb.04.110188.001445. [DOI] [PubMed] [Google Scholar]
- Bermingham E., Lamb T., Avise J. C. Size polymorphism and heteroplasmy in the mitochondrial DNA of lower vertebrates. J Hered. 1986 Jul-Aug;77(4):249–252. doi: 10.1093/oxfordjournals.jhered.a110230. [DOI] [PubMed] [Google Scholar]
- Birky C. W., Jr, Fuerst P., Maruyama T. Organelle gene diversity under migration, mutation, and drift: equilibrium expectations, approach to equilibrium, effects of heteroplasmic cells, and comparison to nuclear genes. Genetics. 1989 Mar;121(3):613–627. doi: 10.1093/genetics/121.3.613. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Birky C. W., Jr Relaxed cellular controls and organelle heredity. Science. 1983 Nov 4;222(4623):468–475. doi: 10.1126/science.6353578. [DOI] [PubMed] [Google Scholar]
- Bonitz S. G., Berlani R., Coruzzi G., Li M., Macino G., Nobrega F. G., Nobrega M. P., Thalenfeld B. E., Tzagoloff A. Codon recognition rules in yeast mitochondria. Proc Natl Acad Sci U S A. 1980 Jun;77(6):3167–3170. doi: 10.1073/pnas.77.6.3167. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dower W. J., Miller J. F., Ragsdale C. W. High efficiency transformation of E. coli by high voltage electroporation. Nucleic Acids Res. 1988 Jul 11;16(13):6127–6145. doi: 10.1093/nar/16.13.6127. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dron M., Rahire M., Rochaix J. D. Sequence of the chloroplast DNA region of Chlamydomonas reinhardii containing the gene of the large subunit of ribulose bisphosphate carboxylase and parts of its flanking genes. J Mol Biol. 1982 Dec 25;162(4):775–793. doi: 10.1016/0022-2836(82)90547-2. [DOI] [PubMed] [Google Scholar]
- Eggertsson G., Söll D. Transfer ribonucleic acid-mediated suppression of termination codons in Escherichia coli. Microbiol Rev. 1988 Sep;52(3):354–374. doi: 10.1128/mr.52.3.354-374.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fournier M. J., Ozeki H. Structure and organization of the transfer ribonucleic acid genes of Escherichia coli K-12. Microbiol Rev. 1985 Dec;49(4):379–397. doi: 10.1128/mr.49.4.379-397.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fox T. D., Weiss-Brummer B. Leaky +1 and -1 frameshift mutations at the same site in a yeast mitochondrial gene. Nature. 1980 Nov 6;288(5786):60–63. doi: 10.1038/288060a0. [DOI] [PubMed] [Google Scholar]
- Goto Y., Nonaka I., Horai S. A mutation in the tRNA(Leu)(UUR) gene associated with the MELAS subgroup of mitochondrial encephalomyopathies. Nature. 1990 Dec 13;348(6302):651–653. doi: 10.1038/348651a0. [DOI] [PubMed] [Google Scholar]
- Grant D. M., Gillham N. W., Boynton J. E. Inheritance of chloroplast DNA in Chlamydomonas reinhardtii. Proc Natl Acad Sci U S A. 1980 Oct;77(10):6067–6071. doi: 10.1073/pnas.77.10.6067. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Harrison R. G., Rand D. M., Wheeler W. C. Mitochondrial DNA size variation within individual crickets. Science. 1985 Jun 21;228(4706):1446–1448. doi: 10.1126/science.228.4706.1446. [DOI] [PubMed] [Google Scholar]
- Hawley D. K., McClure W. R. Compilation and analysis of Escherichia coli promoter DNA sequences. Nucleic Acids Res. 1983 Apr 25;11(8):2237–2255. doi: 10.1093/nar/11.8.2237. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hirsh D. Tryptophan transfer RNA as the UGA suppressor. J Mol Biol. 1971 Jun 14;58(2):439–458. doi: 10.1016/0022-2836(71)90362-7. [DOI] [PubMed] [Google Scholar]
- Hüttenhofer A., Weiss-Brummer B., Dirheimer G., Martin R. P. A novel type of + 1 frameshift suppressor: a base substitution in the anticodon stem of a yeast mitochondrial serine-tRNA causes frameshift suppression. EMBO J. 1990 Feb;9(2):551–558. doi: 10.1002/j.1460-2075.1990.tb08142.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kim D., Johnson J. Construction, expression, and function of a new yeast amber suppressor, tRNATrpA. J Biol Chem. 1988 May 25;263(15):7316–7321. [PubMed] [Google Scholar]
- Kim D., Raymond G. J., Clark S. D., Vranka J. A., Johnson J. D. Yeast tRNATrp genes with anticodons corresponding to UAA and UGA nonsense codons. Nucleic Acids Res. 1990 Jul 25;18(14):4215–4221. doi: 10.1093/nar/18.14.4215. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kobayashi Y., Momoi M. Y., Tominaga K., Momoi T., Nihei K., Yanagisawa M., Kagawa Y., Ohta S. A point mutation in the mitochondrial tRNA(Leu)(UUR) gene in MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes). Biochem Biophys Res Commun. 1990 Dec 31;173(3):816–822. doi: 10.1016/s0006-291x(05)80860-5. [DOI] [PubMed] [Google Scholar]
- Kondo K., Makovec B., Waterston R. H., Hodgkin J. Genetic and molecular analysis of eight tRNA(Trp) amber suppressors in Caenorhabditis elegans. J Mol Biol. 1990 Sep 5;215(1):7–19. doi: 10.1016/S0022-2836(05)80090-7. [DOI] [PubMed] [Google Scholar]
- Lander E. S., Lodish H. Mitochondrial diseases: gene mapping and gene therapy. Cell. 1990 Jun 15;61(6):925–926. doi: 10.1016/0092-8674(90)90055-j. [DOI] [PubMed] [Google Scholar]
- Lauber J., Marsac C., Kadenbach B., Seibel P. Mutations in mitochondrial tRNA genes: a frequent cause of neuromuscular diseases. Nucleic Acids Res. 1991 Apr 11;19(7):1393–1397. doi: 10.1093/nar/19.7.1393. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lewin A. S., Morimoto R., Rabinowitz M. Stable heterogeneity of mitochondrial DNA in grande and petite strains of S. cerevisiae. Plasmid. 1979 Jul;2(3):474–484. doi: 10.1016/0147-619x(79)90031-3. [DOI] [PubMed] [Google Scholar]
- Raftery L. A., Egan J. B., Cline S. W., Yarus M. Defined set of cloned termination suppressors: in vivo activity of isogenetic UAG, UAA, and UGA suppressor tRNAs. J Bacteriol. 1984 Jun;158(3):849–859. doi: 10.1128/jb.158.3.849-859.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Saiki R. K., Gelfand D. H., Stoffel S., Scharf S. J., Higuchi R., Horn G. T., Mullis K. B., Erlich H. A. Primer-directed enzymatic amplification of DNA with a thermostable DNA polymerase. Science. 1988 Jan 29;239(4839):487–491. doi: 10.1126/science.2448875. [DOI] [PubMed] [Google Scholar]
- Sanger F., Nicklen S., Coulson A. R. DNA sequencing with chain-terminating inhibitors. Proc Natl Acad Sci U S A. 1977 Dec;74(12):5463–5467. doi: 10.1073/pnas.74.12.5463. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Shoffner J. M., Lott M. T., Lezza A. M., Seibel P., Ballinger S. W., Wallace D. C. Myoclonic epilepsy and ragged-red fiber disease (MERRF) is associated with a mitochondrial DNA tRNA(Lys) mutation. Cell. 1990 Jun 15;61(6):931–937. doi: 10.1016/0092-8674(90)90059-n. [DOI] [PubMed] [Google Scholar]
- Soll L., Berg P. Recessive lethals: a new class of nonsense suppressors in Escherichia coli. Proc Natl Acad Sci U S A. 1969 Jun;63(2):392–399. doi: 10.1073/pnas.63.2.392. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Soll L. Mutational alterations of tryptophan-specific transfer RNA that generate translation suppressors of the UAA, UAG and UGA nonsense codons. J Mol Biol. 1974 Jun 25;86(2):233–243. doi: 10.1016/0022-2836(74)90015-1. [DOI] [PubMed] [Google Scholar]
- Spreitzer R. J., Goldschmidt-Clermont M., Rahire M., Rochaix J. D. Nonsense mutations in the Chlamydomonas chloroplast gene that codes for the large subunit of ribulosebisphosphate carboxylase/oxygenase. Proc Natl Acad Sci U S A. 1985 Aug;82(16):5460–5464. doi: 10.1073/pnas.82.16.5460. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Spreitzer R. J., Mets L. Photosynthesis-deficient Mutants of Chlamydomonas reinhardii with Associated Light-sensitive Phenotypes. Plant Physiol. 1981 Mar;67(3):565–569. doi: 10.1104/pp.67.3.565. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Spreitzer R. J., Ogren W. L. Rapid recovery of chloroplast mutations affecting ribulosebisphosphate carboxylase/oxygenase in Chlamydomonas reinhardtii. Proc Natl Acad Sci U S A. 1983 Oct;80(20):6293–6297. doi: 10.1073/pnas.80.20.6293. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sugiura M. The chloroplast chromosomes in land plants. Annu Rev Cell Biol. 1989;5:51–70. doi: 10.1146/annurev.cb.05.110189.000411. [DOI] [PubMed] [Google Scholar]
- Yanisch-Perron C., Vieira J., Messing J. Improved M13 phage cloning vectors and host strains: nucleotide sequences of the M13mp18 and pUC19 vectors. Gene. 1985;33(1):103–119. doi: 10.1016/0378-1119(85)90120-9. [DOI] [PubMed] [Google Scholar]
- Zhang D. H., Spreitzer R. J. Nucleotide sequences of the Chlamydomonas reinhardtii chloroplast genes for tryptophan and glycine transfer RNAs. Nucleic Acids Res. 1989 Nov 11;17(21):8873–8873. doi: 10.1093/nar/17.21.8873. [DOI] [PMC free article] [PubMed] [Google Scholar]


