This Article Full Text Full Text (PDF) PPT slides of all figures Supplemental Data All Versions of this Article: 20/9/2324    most recent tpc.108.061747v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Datta, S. Articles by Holm, M. Search for Related Content PubMed PubMed Citation Articles by Datta, S. Articles by Holm, M. Agricola Articles by Datta, S. Articles by Holm, M.

LZF1/SALT TOLERANCE HOMOLOG3, an Arabidopsis B-Box Protein Involved in Light-Dependent Development and Gene Expression, Undergoes COP1-Mediated Ubiquitination^[W]

^a Department of Cell and Molecular Biology, Gothenburg University, 405 30 Gothenburg, Sweden
^b Department of Plant and Environmental Sciences, Gothenburg University, 405 30 Gothenburg, Sweden
^c Department of Plant Molecular Genetics, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Madrid 28049, Spain

⁴ Address correspondence to magnus.holm{at}gu.se.

B-box containing proteins play an important role in light signaling in plants. Here, we identify LIGHT-REGULATED ZINC FINGER1/SALT TOLERANCE HOMOLOG3 (STH3), a B-box encoding gene that genetically interacts with two key regulators of light signaling, ELONGATED HYPOCOTYL5 (HY5) and CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1). STH3 physically interacts with HY5 in vivo and shows a COP1-dependent localization to nuclear speckles when coexpressed with COP1 in plant cells. A T-DNA insertion mutant, sth3, is hyposensitive to high fluence blue, red, and far-red light and has elongated hypocotyls under short days. Analyses of double mutants between sth3, sth2, and hy5 suggest that they have partially overlapping functions. Interestingly, functional assays in protoplasts suggest that STH3 can activate transcription both independently and together with STH2 through the G-box promoter element. Furthermore, sth3 suppresses the cop1 hypocotyl phenotype in the dark as well as the anthocyanin accumulation in the light. Finally, COP1 ubiquitinates STH3 in vitro, suggesting that STH3 is regulated by COP1. In conclusion, we have identified STH3 as a positive regulator of photomorphogenesis acting in concert with STH2 and HY5, while also being a target of COP1-mediated ubiquitination.

This article has been cited by other articles:

				R. Khanna, B. Kronmiller, D. R. Maszle, G. Coupland, M. Holm, T. Mizuno, and S.-H. Wu The Arabidopsis B-Box Zinc Finger Family PLANT CELL, November 1, 2009; 21(11): 3416 - 3420. [Full Text] [PDF]