Abstract
When white-light-grown Lemna gibba plants are placed in the dark, the levels of mRNAs for two nuclear-encoded chloroplast proteins, the small subunit of ribulose-1,5-bisphosphate carboxylase (SSU) and the major chlorophyll a/b-binding protein of light-harvesting complex II (LHCP), decline to a small fraction of their previous level. We have reported [4] that red light (R), acting through phytochrome, and benzyladenine (BA), a synthetic cytokinin, independently stimulate accumulation of both mRNAs in the dark. Here, we have analyzed the products of transcription in isolated nuclei to determine if cytokinins act primarily through stimulation of transcription or if post-transcriptional processes are involved. We find that BA pretreatment may slightly stimulate transcription of LHCP RNA either with or without a red-light treatment. However, the effects of BA on the LHCP RNA accumulation were much greater than on transcription. Two naturally occurring cytokinins are also effective in increasing the mRNA abundance. We therefore conclude that, in Lemna, post-transcriptional processes are important in regulation of the LHCP RNA by cytokinins.
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Abbreviations
- BA:
-
benzyladenine
- di(H)Z:
-
dihydrozeatin
- iP:
-
isopentenyladenine
- LHCP:
-
major chlorophyll a/b-binding polypeptide of light-harvesting complex II
- R:
-
red light
- SSU:
-
small subunit of ribulose-1,5-bisphosphate carboxylase
References
Cleland CF, Briggs WR: Gibberellin and CCC effects on flowering and growth in the long-day plant Lemna gibba G3. Plant Physiol 44: 503–507 (1969).
Colijn CM, Sijmons P, Mol JNM, Kool AJ, Nijkamp HJJ: Light and benzylaminopurine induced changes in ultrastructure and gene expression in plastids of Petunia hybrida cell cultures. Curr Genet 6: 129–135 (1982).
Darnell JE: Variety in the level of gene control in eukaryotic cells. Nature 297: 365–371 (1982).
Flores S, Tobin EM: Benzyladenine modulation of the expression of two genes for nuclear-encoded chloroplast proteins in Lemna gibba: Apparent post-transcriptional regulation. Planta 168: 340–349 (1986).
Flores S, Tobin EM: Benzyladenine regulation of the expression of two nuclear genes for chloroplast protein. In: Fox JE, Jacobs M (eds) Molecular Biology of Plant Growth Control, pp 123–132. Alan R. Liss, New York (1987).
Giles KW, Myers A: An improved diphenylamine method for the estimation of deoxyribonucleic acid. Nature 206: 93 (1965).
Groudine M, Peretz M, Weintraub H: Transcriptional regulation of hemoglobin switching in chicken embryos. Mol Cell Biol 1: 281–288 (1981).
Kannangara CG, Gough SP, Hansen B, Rasmussen JN, Simpson DJ: A homogenizer with replaceable razor blades for bulk isolation of active barley plastids. Carlsberg Res Commun 42: 431–440 (1977).
Karlin-Neumann GA, Kohorn BD, Thornber JP, Tobin EM: Sequence and structure of a chlorophyll a/b-binding protein gene containing an intron with the structure of a transposable element. J Mol Appl Genet 3: 45–61 (1985).
Lehrach H, Diamond D, Wozney JM, Boedtker H: RNA molecular weight determination by gel electrophoresis under denaturing conditions, a critical reexamination. Biochemistry 16: 4743–4751 (1977).
Lerbs S, Lerbs W, Klyachko NL, Romanko EG, Kulaeva ON, Wollgiehn R, Parthier B: Gene expression in cytokinin- and light-mediated plastogenesis of Cucurbita cotyledons: ribulose-1,5-bisphosphate carboxylase/oxygenase. Planta 162: 289–298 (1984).
Maniatis T, Fritsch EF, Sambrook J: Molecular Cloning, 2nd edn. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, NY (1982).
Oota Y: Light- and dark-growth in long-day duckweed, Lemna gibba G-3, as affected by kinetin. Plant Cell Physiol 7: 631–641 (1966).
Parthier B: The role of phytohormones (cytokinins) in chloroplast development. Biochem Physiol Pflanzen 174: 173–214 (1979).
Ross J, Kobs G, Brewer G, Peltz SW: Properties of the exonuclease activity that degrades H4 histone mRNA. J Biol Chem 262: 9374–9381 (1987).
Schneider J, Gruszka M, Legocka J, Szweykowska A: Role of cytokinins in development and metabolism of barley leaves. VII. Effect of light and kinetin on the transcriptional activity of nuclei from etiolated leaves. Biochem Physiol Pflanzen 178: 381–390 (1983).
Silverthorne J, Tobin EM: Demonstration of transcriptional regulation of specific genes by phytochrome. Proc Natl Acad Sci USA 81: 1112–1116 (1984).
Stiekema WJ, Wimpee CF, Silverthorne J, Tobin EM: Phytochrome control of the expression of two nuclear genes encoding chloroplast proteins in Lemna gibba L. G-3. Plant Physiol 72: 717–724 (1983).
Teyssendier de la Serve B, Axelos M, Péaud-Lenoël C: Cytokinins modulate the expression of genes encoding the protein of the light-harvesting chlorophyll a/b complex. Plant Mol Biol 5: 155–163 (1985).
Thomas PS: Hybridization of denatured RNA and small DNA fragments transferred to nitrocellulose. Proc Natl Acad Sci USA 77: 5201–5205 (1980).
Tobin EM, Turkaly E: Kinetin affects rates of degradation of mRNAs encoding two major chloroplast proteins in Lemna gibba L. G-3. J Plant Growth Regul 1: 3–13 (1981).
Tobin EM, Silverthorne J, Flores S, Leutwiler LS, Karlin-Neumann GA: Regulation of the synthesis of two chloroplast proteins encoded by nuclear genes. In: Fox JE, Jacobs M (eds) Molecular Biology of Plant Growth Control, pp 123–132, Alan R. Liss, New York (1987).
Watson JC, Thompson WF: Purification and restriction endonuclease analysis of plant nuclear DNA. Methods Enzymol 118: 57–75 (1986).
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Flores, S., Tobin, E.M. Cytokinin modulation of LHCP mRNA levels: the involvement of post-transcriptional regulation. Plant Mol Biol 11, 409–415 (1988). https://doi.org/10.1007/BF00039021
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DOI: https://doi.org/10.1007/BF00039021