title: Phytochrome control of in vitro transcription of specific genes in isolated nuclei from barley (Hordeum vulgare).
abstract: The transcriptional rates of four different genes in shoots of barley grown under different light regimes were quantified by monitoring nuclear RNA transcripts using gene-specific hybridization probes. Isolated nuclei were pulse-labelled with [alpha-32P]UTP and the relative rates of light-harvesting chlorophyll a/b protein (LHCP) mRNA, NADPH:protochlorophyllide oxidoreductase mRNA, B1 hordein mRNA, and 26-S rRNA synthesis were measured. Irradiation of dark-grown plants with a red light pulse increased the rate of LHCP mRNA synthesis tenfold within 3 h, and the rate of rRNA synthesis more than twofold within 9 h. The relative rate of synthesis of the oxidoreductase mRNA decreased following a red light pulse reaching a minimum after 3-6 h. As a direct proof of phytochrome involvement in the light-induced stimulation of LHCP and the repression of the oxidoreductase transcripts for both responses, red/far-red reversibility could be demonstrated. We conclude that phytochrome is able both to increase the transcription of certain nuclear genes and decrease the transcription of others.
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism*; D002734:Chlorophyll / Q000235:genetics; D004247:DNA / Q000378:metabolism; D002523:Edible Grain / Q000235:genetics*; D005786:Gene Expression Regulation; D001467:Hordeum / Q000235:genetics* / Q000648:ultrastructure; D008027:Light; D045342:Light-Harvesting Protein Complexes; D009693:Nucleic Acid Hybridization; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000235:genetics; D044925:Oxidoreductases Acting on CH-CH Group Donors; D045322:Photosynthetic Reaction Center Complex Proteins; D010834:Phytochrome / Q000502:physiology*; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology*; D012333:RNA, Messenger / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D010834:Phytochrome; D002734:Chlorophyll; D004247:DNA; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; C023886:protochlorophyllide reductase