An evolutionarily conserved protein binding sequence upstream of a plant light-regulated gene. |
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| Authors: | G Giuliano E Pichersky V S Malik M P Timko P A Scolnik A R Cashmore |
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| Affiliation: | Department of Biology, University of Pennsylvania, Philadelphia 19104. |
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| Abstract: | A protein factor, identified in nuclear extracts obtained from tomato (Lycopersicon esculentum, Solanaceae) and Arabidopsis thaliana (Brassicaceae) seedlings, specifically binds upstream sequences from the plant light-regulated gene family encoding the small subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase (RBCS). RBCS upstream sequences from tomato, pea (Pisum sativum, Leguminosae), and Arabidopsis are recognized by the factor. The factor recognition occurs via a short conserved sequence (G box) whose consensus sequence is 5'-TCTTACACGTGGCAYY-3' (where Y is pyrimidine). This sequence is distinct from the GT motif described previously in RBCS promoters. Two other conserved sequences, showing a lesser degree of evolutionary conservation, are found upstream of the G box but do not bind to the G box binding factor (GBF). Twelve nucleotides within the G box are sufficient for the formation of a stable DNA-GBF complex. GBF is found in both light-grown and dark-adapted tomato leaf extracts, but it is present in greatly reduced amounts in root extracts. |
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