TY - JOUR AU - Schäfer, E AB - Abstract Functional cell-free systems may be excellent tools with which to investigate light-dependent signal transduction mechanisms in plants. By evacuolation of parsley protoplasts and subsequent silicon oil gradient centrifugation of lysed evacuolated protoplasts, we obtained a highly pure and concentrated plasma membrane-containing cytosol. Using GT- and G-box DNA elements, we were able to demonstrate a specific localization of a pool of G-box binding activity and factors (GBFs) but not one of GT-box binding activity in this cytosolic fraction. The DNA binding activity of the cytosolic GBFs is modulated in vivo as well as in vitro by light and phosphorylation/dephosphorylation activities. The regulation of cytosolic G-box binding activity by irradiation with continuous white light and phosphorylation correlates with a light-modulated transport of GBFs to the nucleus. This was shown by a GBF-antibody cotranslocation assay in permeabilized, cell-free evacuolated parsley protoplasts. We propose that a light-regulated subcellular displacement of cytosolic GBFs to the nucleus may be an important step in the signal transduction pathway coupling photoreception to light-dependent gene expression. This content is only available as a PDF. © 1994 by American Society of Plant Biologists This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model) TI - Light-regulated modification and nuclear translocation of cytosolic G-box binding factors in parsley. JF - The Plant Cell DO - 10.1105/tpc.6.4.545 DA - 1994-04-01 UR - https://www.deepdyve.com/lp/oxford-university-press/light-regulated-modification-and-nuclear-translocation-of-cytosolic-g-PhBSnOvR04 SP - 545 EP - 559 VL - 6 IS - 4 DP - DeepDyve ER -