Abstract
Chloroplast replication in Euglena gracilis is specifically inhibited by ultraviolet light and the effect is photoreactivable.
The ability of irradiated cells to be photoreactivated is lost more rapidly if cells are incubated in red light than in darkness. A mutant, Y9ZNa1L, which lacks the red-blue photomorphogenic system regulating chloroplast synthesis does not show the red-light-enhanced loss of photoreactivability. Another mutant, Y11P27ZD which has the red-blue system, but lacks the blue-light system also regulating chloroplast synthesis, shows the red-light effect. The red-light effect is seen in a mutant of photosynthetic electron transport, P4ZUL, which rules out a product of photosynthesis as a mediator of the effect. Inhibitors of protein synthesis on chloroplast ribosomes do not prevent the red-light-enhanced loss of chloroplast DNA. Chloroplast DNA is lost rapidly when UV-irradiated cells are incubated in red light, showing that the loss of photoreactivability is due to the loss of the substrate for photoreactivation, chloroplast DNA. Therefore, the red-blue photomorphogenic system is activating a chloroplast DNA-specific nuclease(s). A model is proposed for a light-mediated mechanism regulating the amount of chloroplast DNA: blue light would promote chloroplast DNA synthesis; red light would promote its degradation. The photomorphogenic systems regulating chloroplast synthesis might work by activating a chloroplast-specific modification-restriction mechanism.
Full text
PDF






Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Aaronson S., Ellenbogen B. B., Yellen L. K., Hutner S. H. In vivo differentiation of Euglena cytoplasmic and chloroplast protein synthesis with chloramphenicol and DL-ethionine. Biochem Biophys Res Commun. 1967 Jun 9;27(5):535–538. doi: 10.1016/s0006-291x(67)80020-2. [DOI] [PubMed] [Google Scholar]
- Anderson L. E., Avron M. Light Modulation of Enzyme Activity in Chloroplasts: Generation of Membrane-bound Vicinal-Dithiol Groups by Photosynthetic Electron Transport. Plant Physiol. 1976 Feb;57(2):209–213. doi: 10.1104/pp.57.2.209. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Anderson L. E., Nehrlich S. C., Champigny M. L. Light modulation of enzyme activity: activation of the light effect mediators by reduction and modulation of enzyme activity by thiol-disulfide exchange. Plant Physiol. 1978 Apr;61(4):601–605. doi: 10.1104/pp.61.4.601. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Arnon D. I. COPPER ENZYMES IN ISOLATED CHLOROPLASTS. POLYPHENOLOXIDASE IN BETA VULGARIS. Plant Physiol. 1949 Jan;24(1):1–15. doi: 10.1104/pp.24.1.1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Boyer H. W. DNA restriction and modification mechanisms in bacteria. Annu Rev Microbiol. 1971;25:153–176. doi: 10.1146/annurev.mi.25.100171.001101. [DOI] [PubMed] [Google Scholar]
- Burton W. G., Grabowy C. T., Sager R. Role of methylation in the modification and restriction of chloroplast DNA in Chlamydomonas. Proc Natl Acad Sci U S A. 1979 Mar;76(3):1390–1394. doi: 10.1073/pnas.76.3.1390. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chelm B. K., Hoben P. J., Hallick R. B. Cellular content of chloroplast DNA and chloroplast ribosomal RNA genes in Euglena gracilis during chloroplast development. Biochemistry. 1977 Feb 22;16(4):782–786. doi: 10.1021/bi00623a033. [DOI] [PubMed] [Google Scholar]
- Diamond J., Schiff J. A., Kelner A. Photoreactivating enzyme from euglena and the control of its intracellular level. Arch Biochem Biophys. 1975 Apr;167(2):603–614. doi: 10.1016/0003-9861(75)90504-4. [DOI] [PubMed] [Google Scholar]
- EDELMAN M., SCHIFF J. A., EPSTEIN H. T. STUDIES OF CHLOROPLAST DEVELOPMENT IN EUGLENA. XII. TWO TYPES OF SATELLITE DNA. J Mol Biol. 1965 Apr;11:769–774. doi: 10.1016/s0022-2836(65)80034-1. [DOI] [PubMed] [Google Scholar]
- EISENSTADT J. M., BRAWERMAN G. THE PROTEIN-SYNTHESIZING SYSTEMS FROM THE CYTOPLASM AND THE CHLOROPLASTS OF EUGLENA GRACILIS. J Mol Biol. 1964 Dec;10:392–402. doi: 10.1016/s0022-2836(64)80060-7. [DOI] [PubMed] [Google Scholar]
- Egan J. M., Dorsky D., Schiff J. A. Events Surrounding the Early Development of Euglena Chloroplasts: VI. Action Spectra for the Formation of Chlorophyll, Lag Elimination in Chlorophyll Synthesis, and Appearance of TPN-dependent Triose Phosphate Dehydrogenase and Alkaline DNase Activities. Plant Physiol. 1975 Aug;56(2):318–323. doi: 10.1104/pp.56.2.318. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ganesan A. K., Smith K. C. Dark recovery processes in Escherichia coli irradiated with ultraviolet light. II. Effect of uvr genes on liquid holding recovery. J Bacteriol. 1969 Mar;97(3):1129–1133. doi: 10.1128/jb.97.3.1129-1133.1969. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gibson W. H., Hershberger C. L. Changing proportions of DNA components in Euglena gracilis. Arch Biochem Biophys. 1975 May;168(1):8–14. doi: 10.1016/0003-9861(75)90222-2. [DOI] [PubMed] [Google Scholar]
- Holowinsky A. W., Schiff J. A. Events surrounding the early development of Euglena chloroplasts. I. Induction by preillumination. Plant Physiol. 1970 Mar;45(3):339–347. doi: 10.1104/pp.45.3.339. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LYMAN H., EPSTEIN H. T., SCHIFF J. A. Studies of chloroplast development in Euglena. I. Inactivation of green colony formation by u.v. light. Biochim Biophys Acta. 1961 Jun 24;50:301–309. doi: 10.1016/0006-3002(61)90328-6. [DOI] [PubMed] [Google Scholar]
- Lyman H., Jupp A. S., Larrinua I. Action of Nalidixic Acid on Chloroplast Replication in Euglena gracilis. Plant Physiol. 1975 Feb;55(2):390–392. doi: 10.1104/pp.55.2.390. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Manning J. E., Richards O. C. Synthesis and turnover of Euglena gracilis nuclear and chlorplast deoxyribonucleic acid. Biochemistry. 1972 May 23;11(11):2036–2043. doi: 10.1021/bi00761a007. [DOI] [PubMed] [Google Scholar]
- Mark D. F., Richardson C. C. Escherichia coli thioredoxin: a subunit of bacteriophage T7 DNA polymerase. Proc Natl Acad Sci U S A. 1976 Mar;73(3):780–784. doi: 10.1073/pnas.73.3.780. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rawson J. R., Boerma C. L. A measurement of the fraction of chloroplast DNA transcribed during chloroplast development in Euglena gracilis. Biochemistry. 1976 Feb 10;15(3):588–592. doi: 10.1021/bi00648a021. [DOI] [PubMed] [Google Scholar]
- Rose R. J., Cran D. G., Possingham J. V. Changes in DNA synthesis during cell growth and chloroplast replication in greening spinach leaf disks. J Cell Sci. 1975 Jan;17(1):27–41. doi: 10.1242/jcs.17.1.27. [DOI] [PubMed] [Google Scholar]
- Russell G. K., Draffan A. G. Light-induced Enzyme Formation in a Chlorophyll-less Mutant of Euglena gracilis. Plant Physiol. 1978 Nov;62(5):678–682. doi: 10.1104/pp.62.5.678. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Russell G. K., Lyman H., Heath R. L. Absence of fluorescence quenching in a photosynthetic mutant of Euglena gracilis. Plant Physiol. 1969 Jun;44(6):929–931. doi: 10.1104/pp.44.6.929. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sager R., Kitchin R. Selective silencing of eukaryotic DNA. Science. 1975 Aug 8;189(4201):426–433. [PubMed] [Google Scholar]
- Sager R., Lane D. Molecular basis of maternal inheritance. Proc Natl Acad Sci U S A. 1972 Sep;69(9):2410–2413. doi: 10.1073/pnas.69.9.2410. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Small G. D., Sturgen R. S. Purification and properties of a light-inducible nuclease from Euglena gracilis. Nucleic Acids Res. 1976 May;3(5):1277–1293. doi: 10.1093/nar/3.5.1277. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Stolarsky L., Walfield A. M., Birch R. A., Hershberger C. L. Light-stimulated synthesis of chloroplast DNA. Biochim Biophys Acta. 1976 Apr 2;425(4):438–450. doi: 10.1016/0005-2787(76)90008-3. [DOI] [PubMed] [Google Scholar]
- Uzzo A., Lyman H. Light dependence of temperature-induced bleaching in Euglena gracilis. Biochim Biophys Acta. 1969 Aug 5;180(3):573–575. doi: 10.1016/0005-2728(69)90036-x. [DOI] [PubMed] [Google Scholar]
