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First published online October 21, 2005; 10.1104/pp.105.069963 Plant Physiology 139:1483-1494 (2005) © 2005 American Society of Plant Biologists Functional Interaction between Two Transcription Factors Involved in the Developmental Regulation of a Small Heat Stress Protein Gene Promoter1,[w]Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, Apartado 1052, 41080 Seville, Spain
Hahsp17.6G1 is the promoter of a small heat stress protein (sHSP) from sunflower (Helianthus annuus) that is activated during zygotic embryogenesis, but which does not respond to heat stress. We report here the cloning of a transcription factor (TF), sunflower drought-responsive element binding factor 2 (HaDREB2), by one-hybrid interaction with functional cis-elements in Hahsp17.6G1. We have analyzed the functional interaction between HaDREB2 and a second transcription factor, sunflower heat stress factor A9 (HaHSFA9), which was previously assigned to the regulation of Hahsp17.6G1. HaDREB2 and HaHSFA9 synergistically trans-activate the Hahsp17.6G1 promoter in bombarded sunflower embryos. This synergistic interaction is heat stress factor (HSF) specific and requires the binding of both factors to the promoter. The C-terminal region of HaHSFA9 is sufficient for the HSF specificity. Our results represent an example of a functional interaction between members of the Apetala 2 (HaDREB2) and HSF (HaHSFA9) families of transcription factors. We suggest new roles in zygotic embryogenesis for specific members of the AP2 transcription factor family.
1 This work was supported by the Spanish Ministry of Education and Science (grant no. BIO0201463) and Junta de Andalucía (grant no. CVI148). We also received support from Ph.D. fellowships awarded to J.D.-M. and J.M.E. The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Juan Jordano (fraga{at}cica.es). [w] The online version of this article contains Web-only data. Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.105.069963. * Corresponding author; e-mail fraga{at}cica.es; fax 34954624002. Received August 13, 2005; returned for revision September 7, 2005; accepted September 15, 2005. This article has been cited by other articles:
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