A 268 bp upstream sequence mediates the circadian clock-regulated transcription of the wheat Cab-1 gene in transgenic plants.
We previously reported that the expression of the wheat Cab-1 gene is regulated by an endogenous circadian rhythm and by the photoreceptor phytochrome both in wheat and in transgenic tobacco plants. To define regulatory elements necessary for the circadian rhythm-regulated Cab-1 gene expression, we now analysed the fluctuation of steady-state mRNA levels in a series of 5' deletion mutants in transgenic tobacco plants. We found that the expression of a deletion mutant containing 211 bp upstream sequence still exhibited circadian rhythm. Furthermore we show that an enhancer-like sequence of the Cab-1 promoter (from -357 to -90) can endow a chimaeric gene consisting of a truncated 35S promoter (from -90 to +8) and the bacterial beta-glucuronidase (GUS) gene with circadian clock-regulated gene expression. Finally we demonstrate by nuclear run-off experiments that the transcription rates of the Cab genes in wheat oscillate in a rhythmic manner, with a periodicity of approximately 24 hours. Consistent with our previous findings these results (i) indicate that the expression of the wheat Cab-1 gene is regulated mainly at the transcription level and (ii) identify a short promoter region between -211 and -90 that is responsible for the circadian clock-regulated gene expression.
Fejes
E
E
Institute of Plant Physiology, Biological Research Center of the Hungarian Academy of Sciences, Szeged.
Pay
A
A
Kanevsky
I
I
Szell
M
M
Adam
E
E
Kay
S
S
Nagy
F
F
D000594:Amino Acid Oxidoreductases / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D002940:Circadian Rhythm; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D017343:Genes, Plant; D005813:Genes, Synthetic; D005814:Genes, Viral; D005966:Glucuronidase / Q000096:biosynthesis / Q000235:genetics; D045342:Light-Harvesting Protein Complexes; D008969:Molecular Sequence Data; D009029:Mosaic Viruses / Q000235:genetics; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics*; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid; D012231:Rhizobium / Q000235:genetics; D013728:Terminator Regions, Genetic; D014158:Transcription, Genetic; D014908:Triticum / Q000235:genetics*
D001426:Bacterial Proteins; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D011993:Recombinant Fusion Proteins; D000594:Amino Acid Oxidoreductases; C021883:nopaline synthase; D005966:Glucuronidase